HEXCORDER MILLENNIUM 11

OPERATION MANUAL

Manufactured by:
Cathodic Technology Limited
10 McEwan Drive Bolton Ontario Canada L7E 1H1
Ph ++1 905 857-1050 Fax ++1 905 857-3499
Email ctl@corrosion-rust.com
Hexcorder Millennium II Operation Manual

Warranty
This precision instrument is warranted against defects in materials or workmanship for a period of 12
months from date of sale. This warranty does not cover wear and tear, abuse or misuse of the
equipment. The Hexcorder is water resistant but not water proof and should not be subject to
immersion in liquids or use in rain. For warranty claims, obtain a Return Goods Authorization Form
(RGA Form) from Cathodic Technology Ltd. Carefully package the instrument to prevent shipping
damage and ship the instrument prepaid with the RGA Form to: Cathodic Technology Ltd. 10 McEwan
drive Bolton Ontario Canada L7E 1H1. On receipt of the instrument we will examine the instrument
and determine if it is a valid warranty claim. If we find that the instrument has failed due to defective
materials or workmanship, we will repair or replace at our option.

If the instrument has failed due to wear and tear, abuse or misuse, we will quote the repair cost. No
repairs will be undertaken until the cost of repair, packaging and shipping are paid in full.

Testing
This instrument has been thoroughly tested and has undergone a burn in test. The instrument has been
tested under actual field conditions and meets the quality control standards of Cathodic Technology Ltd.

Calibration
The instrument comes with a certificate of calibration traceable to the US National institute of
Standards (NIST) or National Research Council of Canada (NRC). This certificate of calibration is
valid for one year from date of purchase and should be renewed on an annual basis.

2 Cath-Tech™
Hexcorder Millennium II Operation Manual

Index
Unpacking and Inspection...................................................................................................................6
Hexcorder Connections.......................................................................................................................7
Wire Dispensers ..................................................................................................................................8
Threading the Chainage Counter ............................................................................................9
Charging the Battery ...........................................................................................................................9
Programming the Hexcorder.............................................................................................................10
KEYBOARD Etiquette.....................................................................................................................10
Main Menu....................................................................................................................................11
The Setup Procedure .........................................................................................................................11
File Number ..................................................................................................................................12
Survey Type ..................................................................................................................................12
Distance Standard .........................................................................................................................13
Measurement Method ...................................................................................................................13
Non Interrupted.....................................................................................................................13
High/Low ..............................................................................................................................14
GPS Synchronized ................................................................................................................15
Interruption Cycle .................................................................................................................15
OFF Potential Delay .............................................................................................................16
Power System Frequency......................................................................................................17
Store GPS Coordinates .........................................................................................................17
Data Recording Methods ......................................................................................................17
Record by Distance ...............................................................................................................18
Setup Display ........................................................................................................................18
Starting Chainage..................................................................................................................18
Increment +/-.........................................................................................................................19
Survey Description................................................................................................................19
Main Menu............................................................................................................................19
CIPS Survey’s...................................................................................................................................21
CIPS Numeric Survey Screen.......................................................................................................21
CIPS Graph Screen .......................................................................................................................22
Graph Range .........................................................................................................................22
DCVG Survey’s ................................................................................................................................23
DCVG Numeric Survey Screen ....................................................................................................24
DCVG Graph Screen ....................................................................................................................25
Data Logger Setup ................................................................................................................26
Data Logger Display .............................................................................................................26
DVM Function ..................................................................................................................................27
DVM Setup ...................................................................................................................................27
AC or DC Measurement ...............................................................................................................27
AC measurement Ranges......................................................................................................28
DC measurement Ranges......................................................................................................28
Manual or Auto Ranging ......................................................................................................28
Input Impedance....................................................................................................................30
AC Filter ...............................................................................................................................30
Store DVM Reading .............................................................................................................31
Export Data ...................................................................................................................................31

Cath-Tech™ 3
Hexcorder Millennium II Operation Manual
S-Setup..........................................................................................................................................32
Baud Rate..............................................................................................................................32
Sign Convention....................................................................................................................32
Distance Standard .................................................................................................................32
Data Format ..........................................................................................................................33
File Directory ........................................................................................................................33
Test Function ....................................................................................................................................34
Test Function Menu Screen ..........................................................................................................34
Alarms...................................................................................................................................34
Wire (Distance).....................................................................................................................34
Potential ................................................................................................................................34
PDOP ....................................................................................................................................35
Cancel Alarm ........................................................................................................................35
Memory Test.........................................................................................................................35
EPROM Test.........................................................................................................................36
Editing Quick Menu..............................................................................................................36
Satellites................................................................................................................................37
Set Clock...............................................................................................................................37
Erase Memory Function........................................................................................................38
Wave .....................................................................................................................................38
WAVEFORM SCALE..........................................................................................................39
Storing a Waveform......................................................................................................................40
Waveform File Number ........................................................................................................41
GPS Engine...................................................................................................................................41
Sub-Metre GPS .............................................................................................................................42
Charging The Sub-Metre Engine Battery .....................................................................................43
SUB-Metre GPS Connection ........................................................................................................44
Hyper Terminal Set-up .................................................................................................................45
Configuring The Hexcorder for Communication .........................................................................47
Main Menu Press 3 ...............................................................................................................47
Export Data Menu.................................................................................................................47
S - Set-Up......................................................................................................................................48
Export Data Setup .................................................................................................................48
Baud Rate..............................................................................................................................48
Sign Convention....................................................................................................................48
Signs Inverted = Negative.................................................................................................48
Export Data Menu.................................................................................................................49
D - Directory .................................................................................................................................49
File Directory ........................................................................................................................49
Memory Information.............................................................................................................49
F - Select Survey File....................................................................................................................50
Capture Data: ........................................................................................................................50
Datum................................................................................................................................................52
Survey Technique .............................................................................................................................57
Close Interval Potential Surveys (CIPS).......................................................................................57
Graph of CIPS Survey ..........................................................................................................58
DCVG Surveys .............................................................................................................................59
CIPS + DCVG with a Pipe Connection ................................................................................59
DCVG no Pipe Connection...........................................................................................................60
4 Cath-Tech™
Hexcorder Millennium II Operation Manual
DCVG Gradient Patterns ..............................................................................................................61
DCVG Calculations ..............................................................................................................61
Cathodic Protection and Coating Defects .........................................................................................62

Cath-Tech™ 5
Hexcorder Millennium II Operation Manual

Unpacking and Inspection

On receipt of this precision instrument unpack carefully and examine for damage in transit. If damage
is detected, file a claim with the carrier immediately. If damage is not detected verify that you received
all of the pieces.

Hexcorder Millennium Hexcorder Millennium 11

with WAAS GPS With Sub-Metre GPS

Backpack Wire Dispenser Hip Pack Wire Dispenser

Fiberglass Half Cell Extension Poles

6 Cath-Tech™
Hexcorder Millennium II Operation Manual

Hexcorder, complete with: OR

• Wire Dispenser
• Battery Charger Backpack wire
• 2 X CuCuSO4 half cells dispenser instead of
• Umbilical cord wire dispenser Hip-pack wire dispenser
to Hexcorder
• 2 X Half Cell extension poles
• 2 X Cables Half Cell poles to
Hexcorder
• Operation manual

Integrated SUB-Metre GPS

Engine available as an option

Hexcorder Connections
Neck Strap

Half-cell Poles connect to

Bulkhead connectors on
front of instrument

Cath-Tech™ 7
Hexcorder Millennium II Operation Manual

Battery Charger
connects here

Backpack or Hip-pack
wire dispenser
connects here

Wire Dispensers
Backpack
Wire
Dispenser

Hip pack
Wire
Dispenser

8 Cath-Tech™
Hexcorder Millennium II Operation Manual

Threading the Chainage Counter

Wire exits from
Chainage Counter

Top Tensioner

Counter Drum

Bottom Tensioner

Wire from spool

The 32 gauge varnished magnet wire comes up from the bottom, over the lower tensioner, around the
counter drum twice counter clock wise and exits over the top tensioner. The magnet wire must go
between the two spring loaded disks of the tensioner, adjust the spring pressure just tight enough to
prevent slippage of the wire on the counter drum.

Connect the lead from the centre of the spool of wire to the terminal provided on the wire dispenser.
Make sure that you remove the varnish or enamel from the wire where it connects to the terminal or
pipe.

The light survey wire is sold by weight, small spools for the hip-pack weigh approximately 1 Kg and
contain approximately 2 Km of #32 gauge enameled magnet wire. The big spools for the backpack
hold approximately 5 Kg of wire, approximately 10 Km of #32 gauge survey wire.

Charging the Battery

The battery is the latest generation of rechargeable nickel metal hydride (NMH). NMH does not
develop a memory, if looked after will provide many years of service. Do not allow the battery to
freeze, likewise do not store in a hot location.

Initially charge the battery for 16 hours; thereafter charge overnight before each day’s survey.

The nominal battery voltage is 7.2 volts and when charging may exhibit voltages as high as 8.2 volts.
The battery is exhausted when the voltage drops to 6.5 volts.

The Graphica (CIPS) and the DCVG Hexcorder’s have 4.0 Amp hours of battery capacity and the
Millennium has 8.0 amp hours of battery capacity.

Cath-Tech™ 9
Hexcorder Millennium II Operation Manual

GPS Engine

Battery
Charger
Connects
here

Programming the Hexcorder

To turn on the Hexcorder press the upper Yellow Key on the keyboard

This key
turns the
Hexcorder
ON

Press the
two yellow
keys
together to
reset or
return to
main menu

KEYBOARD Etiquette
The Hexcorder priority is to measure distance, measure the pipe-to-soil potentials and the voltage
gradient, monitor the GPS engine, write all of this information to the LCD screen and store the
information on command. Do not press hard or repeatedly press the key.

When in survey mode, the keyboard is

lowest priority. To change from survey
mode to the menu system press the key
gently and hold for 5 seconds to allow the
Hexcorder to recognize your command.
10 Cath-Tech™
Hexcorder Millennium II Operation Manual

Main Menu
The main menu appears after the Hecorder boots up.
Main Menu

Before you can perform a survey you must go through the set up procedure to configure the Hexcorder
for the type of survey you want to undertake and what data and information that you want stored with
each reading.
The Setup Procedure
Press 2 at the main menu to enter the setup procedure

The Hexcorder will display the last setup that was used for survey.

After erasing the memory it is necessary to

fully reprogram the Hexcorder by
completing the setup procedure

Press C at the setup screen to change or update the setup.

The following steps must be completed:

Cath-Tech™ 11
Hexcorder Millennium II Operation Manual

File Number

The Hexcorder automatically increments the file number when C for change is pressed in the Setup
Menu. After erasing the memory the Hexcorder will show File 1, accept this file by pressing A to
accept. To give the file a name (max 8 characters) press N then type in a file name with a maximum of
eight characters. If the file name is less than eight characters use the space key to add characters. Up to
50 survey files can be stored in memory.

Survey Type

Select the type of survey or data logging function.

C – close interval surveys

D-Data-Logger use the 15 pin D connector on the

front of the Hexcorder for data logger input

V - CIPS+DCVG Combined close interval and voltage gradient survey with a

pipe conection

G – DCVG without a pipe connection

S-Side drain survey use 15 pin D connector on front of Hexcorder for input

When the survey mode is selected then the following screens will appear. The following procedure
allows you to customize your survey and data to be stored with each reading.

12 Cath-Tech™
Hexcorder Millennium II Operation Manual

Distance Standard

Select 1 for metric distance measurement or 2 for imperial distance measurement (Feet)

Measurement Method

There are three survey methods, they are selected by pressing the C for change key. The three survey
methods are:

Non interrupted – Used for sacrificial systems or unprotected pipe

High/Low – used when GPS synchronized interrupters are not available.

GPS Synchronized – the most accurate survey method for determining the rectifier ON
and Instant OFF potentials.

Non Interrupted

This method measures the pipe-to-soil potential several times per second and displays the potential on
the LCD screen.

Non-Interrupted setup screen

Cath-Tech™ 13
Hexcorder Millennium II Operation Manual

Non-Interrupted Survey Screen

The pipe-to-soil potential can be stored at any time by pressing the red button on the half cell stick or
the ENTER key on the keyboard.

High/Low

This method finds the highest and lowest reading during the programmed interruption cycle. This
method is principally used with non GPS synchronized interrupters

The High/Low selection

The High/Low survey screen

14 Cath-Tech™
Hexcorder Millennium II Operation Manual

GPS Synchronized

This method uses the GPS engine and initiates measurement of the rectifier OFF potential on receipt of
the 1 PPS timing signal from the GPS satellite system. This is the most accurate of the survey methods.
GPS synchronized interrupters that turn the rectifier OFF on receipt of the 1PPS
timing signal must be utilized with this survey method.

The GPS Synchronized selection screen

The GPS Synchronized survey screen

Interruption Cycle

The Hexcorder needs to know the current interrupter cycle for High/Low and GPS synchronized modes
of survey.

Enter the rectifier OFF time in milliseconds.

Cath-Tech™ 15
Hexcorder Millennium II Operation Manual

Enter the rectifier interruption cycle time in seconds.

Cycle = OFF Time + ON time

Note: The programmed rectifier ON and OFF times must exactly match the rectifier ON and OFF times
programmed in the current interrupters.

OFF Potential Delay

In GPS synchronized mode we can have increased survey accuracy by programming a delay after the
GPS interrupters turn the rectifier OFF before measuring the rectifier OFF potentials.

Enter the delay time in milliseconds after receipt of the 1 PPS signal before reading the rectifier OFF
potential.

The allowable delay time is dependent on the length of time that the rectifier is OFF. Do not exceed the
following delay times:

100 Milliseconds OFF........................................................................................................................... No delay

200 Milliseconds 50 Millisecond delay
300 Milliseconds 100 Milliseconds
400 Milliseconds 200 Milliseconds
500 Milliseconds 300 Milliseconds

Note: With GPS synchronization it is not necessary to have long interruption cycles the Hexcorder is
quite capable of correctly measuring the rectifier ON and instant OFF potential every second.

16 Cath-Tech™
Hexcorder Millennium II Operation Manual
Power System Frequency
The Hexcorder needs to know the power system frequency where you are surveying in order to properly
configure the AC filter.

Select the power system frequency for your work area. North and Central America have 60 cycle
power system frequency, whereas Europe and Asia have 50 hertz power system frequency. Select the
power system frequency for your area.

Store GPS Coordinates

The Hexcorder gives you the option in all three survey modes of storing the GPS coordinates and time.

Data Recording Methods

The Hexcorder can be programmed to record the measurements in one of three ways.

Manual – Push the Button

Distance – Record based on distance
Time – Record based on time (Only in GPS Synchronized Mode)

Cath-Tech™ 17
Hexcorder Millennium II Operation Manual
Record by Distance

If you have selected record by distance you now need to enter the distance between readings.

Recording based on time can only be used in GPS synchronized mode, the Hexcorder utilizes the GPS
1pps signal to initiate the reading.

After you have selected the measurement recording method the Hexcorder again displays the set-up
screen and wants you to confirm that it is correct.

Setup Display

If you accept your programming by pressing A to accept then the Hexcorder displays some additional
screens.
If F is pressed for new file, a new screen appears allowing you to change the file name.

Starting Chainage

Enter the chainage for your location or starting point.

18 Cath-Tech™
Hexcorder Millennium II Operation Manual
Increment +/-

Then enter the increment; + to increase the chainage and – to decrease the chainage.

To toggle between + and – pres the C for change key. When you have the correct setting press A to
accept the setting.

the enter key to conclude the entry and return to the main menu

Survey Description

The Hexcorder then asks for a description of the survey, Please enter a description and when you are
finished press ENTER to store the description as a header on your data.

After entering a description of the survey the Hexcorder returns to the main menu. At this point you can
undertake a survey by pressing 1 for survey

Main Menu

GPS Coordinates

Cath-Tech™ 19
Hexcorder Millennium II Operation Manual

When the GPS engine is turned on and it has acquired a position from the satellites, the latitude and
longitude are displayed on the main menu.

To start a new file using the same program press the two yellow keys to return to the main menu then
press 2 for setup then press “F” for a new file, A new screen appers displaying the new file number.
You can add a file name to the file by pressing “N” to change file name. Type the new file name, limit
8 characters. If the file name is less than 8 characters use space to make up the characters, Press A to
accept to accept the new file.

Anew screen will appear showing the chainage and giving you the opportunity to change or update the
chainage.

The incrimination screen appears, set the incrimination to + or –

20 Cath-Tech™
Hexcorder Millennium II Operation Manual

The Hexcorder then asks you to enter a description of the survey file. Type a description of the survey
you are about to do then press the enter key to write your description to memory and return to the main
menu.

The main menu appears, if you have the GPS engine on and it has a lock on the satellites you will see
the coordinates displayed on the main menu screen.

To undertake a survey after going through the setup procedure press 1 for Survey.

CIPS Survey’s

CIPS Numeric Survey Screen

The survey screen displays the pipe-to-soil potential measured by the Hexcorder. If in GPS
synchronized or high/low mode it displays the rectifier ON and instant OFF potentials. The Millennium
in addition to displaying the rectifier ON and instant OFF potentials can measure and display the
rectifier On and OFF voltage gradient.

Cath-Tech™ 21
Hexcorder Millennium II Operation Manual
The survey screen also displays the record number which is the number of readings taken since the start
of the file. The chainage is also shown along with the % of memory used.

The Hexcorder can also display the survey screen in Graphics mode were the readings are displayed
both numerically and graphically.

CIPS Graph Screen

In addition to a numeric survey display screen the Hexcorder can display the pipe-to-soil potentials in
graphic form.

Graph Range

When the graph screen is selected by pressing and holding the G key for 5 seconds when the numeric
survey screen is displayed a graph range menu is displayed.

Press 1,2 or 3 depending on the graph scale that you desire.

To return to the numeric display screen press and hold the G key for 5 seconds.

22 Cath-Tech™
Hexcorder Millennium II Operation Manual

DCVG Survey’s
Programming for a DCVG survey is identical to programming for a CIPS survey with a few differences.
When selecting survey type, there are two methods of undertaking a DCVG survey, firstly as a DCVG
survey combined with a CIPS survey and secondly as a DCVG survey with out a pipe connection.

DCVG surveys can be undertaken using GPS synchronized or High Low software. The GPS
synchronized is more accurate and quicker than high-low.

Select the Type of DCVG Survey

V – CIPS + DCVG (with a pipe connection)

G – DCVG (Without a pipe connection)

If G is selected for DCVG without a pipe connection the following survey screen appears.

The screen displays the voltage gradient by measuring the potential between the two half cells with the
rectifier current applied then measuring the potential between the half cells with the current interrupted.
The voltage gradient displayed is the difference between the gradient with the rectifier On and OFF.

The bar graph represents the voltage gradient and current flow direction. The bar graph has three
ranges.

1 = 10 Millivolts
5 = 50 Millivolts
0 = 100 Millivolts

Cath-Tech™ 23
Hexcorder Millennium II Operation Manual
For example when the bar graph is displayed press and hold the 5 key for 5 seconds to change the bar
graph range to 50 millivolts.

A bar graph staring at the left edge of the screen indicates current flow from the left half cell towards
the right half cell. The left edge is 0 millivolts and the right edge is either 10, 50 or 100 millivolts
depending on the graph range selected.

A bar graph starting at the right edge of the display and progressing towards the left edge represents
current flow from the right half cell towards the left half cell.

DCVG With A Pipe Connection

DCVG Numeric Survey Screen

The survey screen displays the pipe-to-soil potential measured by the Hexcorder. If in GPS
synchronized or high/low mode it displays the rectifier ON and instant OFF potentials.

In CIPS+DCVG mode it can also displays the ON and OFF voltage gradient or only the difference
between the ON and OFF gradient as well as a bar graph representing the voltage gradient measured
between the two half cells.

The direction and magnitude of the voltage gradient is depicted by the size of the bar graph and the
starting point of the bar graph as described earlier in DCVG without a pipe connection.

To display both the ON and OFF voltage gradient values pree and hold the “O” key for 5 seconds. To
display the differnce between the On and OFF voltage gradients press and hold the ‘P” key for 5
seconds.

24 Cath-Tech™
Hexcorder Millennium II Operation Manual

The Millennium in addition to displaying the rectifier ON and instant OFF potentials can measure and
display the rectifier ON and OFF voltage gradient, or the difference between the two.

The survey screen also displays the record number which is the number of readings taken since the start
of the file, . the chainage, the % of memory used, the GPS coordinates, the signal quality, the elivation,
the PDOP value.

DCVG Graph Screen

Select the graph range

In addition to a numeric survey display screen the Hexcorder can display the pipe-to-soil potentials in
graphic form.

Cath-Tech™ 25
Hexcorder Millennium II Operation Manual

Data logger

When D for data logger is selected the Hexcorder can record data simultaneously on 5 common
negative input channels. The 15 pin D connector on the front of the Hexcorder is used for the data
logger inputs. A cable with each channel clearly labeled is supplied with the Hexcorder.

To utilize the data logger function it is necessary to use the setup program to program the Hexcorder to
perform the task.

At the setup screen press C to change then follow the prompts.

Data Logger Setup

Set the number of channels to be logged and the logging frequency. The Hexcorder will then display
the Data Logger display and begin logging data on the programmed time interval.

Data Logger Display

26 Cath-Tech™
Hexcorder Millennium II Operation Manual

DVM Function
The DVM function can measure both AC and DC voltages. The Hexcorder is equipped with banana
plug sockets on the right side of the instrument for the DVM function. Use the test leads supplied
plugged into the appropriate sockets.

Wire Dispenser DVM Connectors Battery Charger

From the main menu press D for DVM or in the QUICK Menu (White Key) when in survey mode,
press 4 for the DVM function the DVM setup screen appears.

DVM Setup
Press C to toggle between AC or DC voltage measurement.

AC or DC Measurement
Press C to toggle between AC or DC measurement.

Cath-Tech™ 27
Hexcorder Millennium II Operation Manual
AC measurement Ranges

• 40 Volt
• 400 Volt

DC measurement Ranges

• 40 mV
• 400 mV
• 4000 mV
• 40 Volt
• 400 Volt

Manual or Auto Ranging

In both AC and DC measurements, you can select auto ranging or manual range.

Press C to toggle between auto ranging and manual.

If manual is selected the measurement screens are as follows

28 Cath-Tech™
Hexcorder Millennium II Operation Manual

After selecting the appropriate voltage range press A to accept.

In auto ranging the Hexcorder will select the most appropriate measurement range.

Next the Hexcorder asks for the input impedance that you require.

Press C to toggle to the required input impedance.

Cath-Tech™ 29
Hexcorder Millennium II Operation Manual
Input Impedance

For AC measurement the input impedance is fixed at 100 Meg Ohms.

For DC measurement the available input impedance are:

• 10 Meg Ohm
• 100 Meg Ohm
• 1000 Meg Ohm

After selecting the required input impedance, the measurement screen appears.

AC Filter

The Hexcorder asks if you would like the AC filter turned ON.

To turn the AC filter ON or OFF press C for change and it will toggle between ON and OFF, then press
A to accept the selection.

30 Cath-Tech™
Hexcorder Millennium II Operation Manual
Store DVM Reading

Press ENTER to store the reading in memory.

When in survey mode, the reading is stored in the comment field of the survey file.

If the DVM function is being used as a stand alone function the values are stored in a special file. GPS
coordinates and time may be stored with the values if the GPS engine is turned ON and locked.

Other Functions
Export Data

The export data function has five options:

S – Setup (Used to set the export data baud rate)

D – Directory (List all the files stored in memory)

F – Select Survey File (Select the survey file to export)

W – Select Waveform File (Select the waveform file)

Cath-Tech™ 31
Hexcorder Millennium II Operation Manual

H – Hexdump (Exports content of memory in hexadecimal format)

The first time you need to export data make sure you set the baud rate on the Hexcorder to match the
baud rate of your computers COM PORT. We recommend that you use a baud rate of 19,200 baud.

S-Setup

Baud Rate

After you have set the baud rate the Hexcorder asks several more set up questions.

Sign Convention

Signs inverted places a –ve sign in front of the pipe-to-soil potential. This can be changed to signs
normal no negative sign by pressing the C for change key. When you have the proper selection press A
to accept and advance to the next screen.

Distance Standard

32 Cath-Tech™
Hexcorder Millennium II Operation Manual

Regardless of whether you stored distance in metric or imperial you can export the distance in either
standard. Select the distance standard that you want your data exported in and a new screen appears:

Data Format

The choices are ASCII comma delimited text file or ProActive.

When you have finished the setup, print of a directory of the files stored in memory this will confirm
communication then export the survey and waveform files to your PC.

File Directory

Cath-Tech™ 33
Hexcorder Millennium II Operation Manual

Test Function
To enter the test function press 5 from he main menu

Test Function Menu Screen

Alarms

Under the test function, the alarms for potential, distance and PDOP can be enabled or disabled.

Wire (Distance)
Distance – If the distance does not increment between readings the instrument beeps and flashes
‘CHECK WIRE”. (Indicates possible broken wire)

Potential

Potential – If the potential changes more than 50% between readings the Hexcorder Alarms and beeps
and on the display it flashes “CHECK POTENTIAL”. (Indicates possible broken wire or reading
problem)

34 Cath-Tech™
Hexcorder Millennium II Operation Manual

PDOP

PDOP – this alarm is programmable and refers to the accuracy of the GPS signal. Set this alarm to a
value higher than 6.0

If the PDOP alarm is enabled then you must enter a value.

A good quality signal will have a PDOP value of 2 to 3 thus the PDOP alarm should be set to a value
greater than 6 to avoid nuisance alarms.

Cancel Alarm
To acknowledge and silence the alarm press A

Note: To acknowledge and cancel

the alarm press the A key on the
keyboard

Memory Test

This tests the integrity of the CMOS non volatile RAM memory. Do not touch the keyboard during this
test as the memory is being fully tested and any interruption could result in loss of data.

At the end of the memory test the Hexcorder will display the number of Good bytes of memory. This
value should match the memory size you purchased.

Cath-Tech™ 35
Hexcorder Millennium II Operation Manual

EPROM Test

The EPROM which contains the operating program can also be tested, press E for EPROM test and the
following screen appears.

The Hexadecimal values must exactly match, if not then the EPROM is damaged or counterfeit.

Editing Quick Menu

The quick menu can be edited from the Test Menu 5, press Q for quick menu.

The cursor will be found flashing on the first editable comment. To change the comment type the new
comment, maximum 8 characters. To move forward through the screen to edit another comment hold
down the menu key and press B, to move back press and hold the menu key then press V. To restore
the default “quick menu”, press menu + 0 simultaneously. The quick menu allows the surveyor to
insert comments in the survey data stream with two key strokes.

36 Cath-Tech™
Hexcorder Millennium II Operation Manual
Satellites
The satellite screen is displayed which provides information about the GPS satellites being received and
other information.

The screen list the satellites received by satellite number, If the 1PPS signal is being received, The
PDOP value, The quality ( 1 = No differential correction, 2 = WAAS differential correction), The UTC
date and time, The position (Latitude and Longitude), the number of satellites being received, the
altitude in metres.

To exit this screen press the two yellow keys simultaneously.

Main Menu Functions Continued

Set Clock

The set time and date function is accessible from the main menu, press 4 to change or set the time and
date.

The time and date should be entered using the following format:

yy = Last 2 digits of year

mm = Month

dd = Day of month

w = Week day (Monday = 1)

hh = Hour in 24 hour clock

Cath-Tech™ 37
Hexcorder Millennium II Operation Manual
mm = Minutes

ss = Seconds

Erase Memory Function

Occasionally it will be necessary to erase the memory to remove old data from the Hexcorder. When
the erase memory function is used the data is removed from memory and unrecoverable. Please make
sure your data is backed up on another device before erasing the memory.

The Hexcorder questions you by asking “ARE YOU SURE Y/N” if you are sure that you want to
erase the memory press ‘Y” if you do not want to erase the memory press “N” to exit the erase memory
function.

Wave

The Hexcorder has a special function called Wave, in the wave function the Hexcorder can record and
store 2,000 readings per second for the duration of the reading cycle. If you are operating a 1 second
interruption cycle then the Hexcorder will record and store 2,000 readings in memory. If however your
interruption cycle is 4 seconds, 1 second OFF and 3 seconds ON the Hexcorder will record and store
8,000 readings.

The waveform function can be accessed three different ways.

• From the main menu press the W key for Wave

• From the Quick menu key, when in survey mode, by pressing the W key for Wave.

• From the Keyboard when in survey mode by pressing S for Scope.

When the wave function is selected, the following screen appears:

38 Cath-Tech™
Hexcorder Millennium II Operation Manual

The first screen shows all of the data recorded in 100 milliseconds use the arrow keys (Key V for left
and Key B for right to move through the graph.

The range of the graph is preset and the current range is displayed in the upper right, and lower right of
the screen display the range. These numbers represent the upper and lower voltage limits of the screen.
Press the S key can change the range.

When the S key is pressed a new screen appears and the upper and lower limits of the graph can be set.

WAVEFORM SCALE

Press the C Key to change the scale

Press C to change the upper limit and enter a 5 digit number representing the upper voltage limit of the
graph.

In this case we changed the upper voltage limit to 3000 millivolts

If you do not want to change the upper voltage limit, press A to accept the setting.

When A for accept is pressed a new screen appears requesting you to accept or change the sign.

Cath-Tech™ 39
Hexcorder Millennium II Operation Manual

These steps are repeated for the lower voltage limit. When the final acceptance is entered the screen
reverts back to the graph display of the Waveform with the new settings.

To end the Waveform session press the “ENTER” key and a new message appears showing the upper
and lower limits for the waveform.

Storing a Waveform
Press the enter key on the keyboard when the waveform is displayed on the LCD display and the
Hexcorder will ask if you want the waveform stored in memory.

If N is pressed the waveform data is discarded and the Hexcorder returns to the previous screen or
operation.

If Y is pressed the waveform will be stored and the following screen appears.

40 Cath-Tech™
Hexcorder Millennium II Operation Manual
Waveform File Number

Press N to add a eight digit file name to the file number.

To complete the storage of the waveform data press A to accept.

The number of screens in the Waveform mode, is dependent on the interruption cycle. Each screen
represents a 100 milliseconds (0.1 second) slice of time.

To store the waveform data or to exit waveform mode press the Yellow ENTER Key.

GPS Engine
The standard GPS engine supplied with the Hexcorder is a 12 satellite WAAS enabled GPS engine
capable of resolving position information with an accuracy of 1 to 3 metres if the WAAS differential
correction is being received. The standard GPS engine supplied with the Hexcorder can also be
equipped with a beacon receiver which will yield 1 metre accuracy where the beacon transmission can
be received. The beacon receiver is sold as an accessory item, contact Cathodic technology limited for
price and delivery.

All CATH-TECH Hexcorder’s can be equipped with a sub-metre engine integrated into the survey
instrument. For more accurate position information, contact the factory for a delivery and price GPS
upgrade to sub-metre coordinate accuracy.

Cath-Tech™ 41
Hexcorder Millennium II Operation Manual

Sub-Metre GPS
SUB-Metre GPS Engine

The above picture shows the Hexcorder with integrated sub-metre GPS engine capable of resolving
position information with an accuracy of less than 1 metre world wide.

The sub-metre engine uses a separate battery pack due to its heavy power demand (3 watts). The sub-
metre engine battery pack is a 12 volt 4 AH nickel metal hydride battery and has a 12 volt battery
charger. Do not mix up

42 Cath-Tech™
Hexcorder Millennium II Operation Manual

Charging The Sub-Metre Engine Battery

the Hexcorder charger 7.2 volt with the sub-metre charger 12 volt.

Power switch Charge Connector

GPS Engine ON

Battery Charge Indicator

Cath-Tech™ 43
Hexcorder Millennium II Operation Manual

SUB-Metre GPS Connection

The sub-metre GPS engine connects to the hexcorder using the supplied 9 pin D connector. The GPS
port id on the left side of the Hexcorder body and is labbled.

Communicating with a PC
To communicate with the Hexcorder a PC equipped with a terminal emulation program such as
Windows Hyper terminal, Mirror, PC-Term, Pro-Com Etc is required.

The following steps illustrate how to configure Windows Hyper Terminal for communication with the
Hexcorder. Configuring other Terminal Emulation programs will be similar.

To find Windows Hyper Terminal go to:

44 Cath-Tech™
Hexcorder Millennium II Operation Manual

Hyper Terminal Set-up

Windows Start Button (Click on Start)

Programs Drag the Mouse from Programs to Accessories

Accessories Drag the mouse from Accessories to Communication

Communication Drag the mouse from communication to the Hyper Terminal Folder then
Click to open Hyper Terminal

Hyper Terminal Click on

Hyper terminal.exe

In Windows desktop click on START

This is the HyperTerminal
set up selection

New Connection Enter Hexcorder then click OK

Cath-Tech™ 45
Hexcorder Millennium II Operation Manual

Connect Using Click and change to Direct to Com 1 Click OK

Port Settings Click on the arrows to change the settings to the following:

Bits per Second 19200

Data Bits 8

Parity NON

Stop Bits 1

Flow Control X – ON X – OFF

Then Click OK and you will be in the Hyper Terminal communication screen.
46 Cath-Tech™
Hexcorder Millennium II Operation Manual

Configuring The Hexcorder for Communication

Connect the Hexcorder to your PC using the supplied 9 pin cable.

Turn on the Hexcorder by pressing the yellow (ON) key

Main Menu Press 3

At the Main Menu press 3 for Export data

The Export Data Menu Screen appears:

Export Data Menu

Press S for Set-Up

Cath-Tech™ 47
Hexcorder Millennium II Operation Manual

S - Set-Up

Export Data Setup

Baud Rate

The baud rate can be set at any speed between 50 and 38,400 bits per second; the common baud rates
are 1,200, 2,400, 4,800, 9,600, 19,200 and 38,400. The default baud rate is 38,400.
Pressing C to change and entering the new baud rate can change the baud rate. Make sure that your PC
is also set to the same baud rate or transmission difficulties will occur.
After the baud rate is selected a new screen appears:

Sign Convention

At this screen the sign transmitted with the data can be changed, with signs normal the leading – minus
sign is not transmitted with the data. If signs inverted is selected a leading – sign is placed in front of
the data.

Signs Normal = No negative sign

Signs Inverted = Negative

sign in front of potential value

The HEXCORDER Millennium 11 then returns to the export data menu.

48 Cath-Tech™
Hexcorder Millennium II Operation Manual

Export Data Menu

Note: At this stage you can confirm communication with your PC by pressing the D key. This will send
the file directory to your PC and it should appear on your Video Display Terminal

D - Directory
Select D for directory and the following screen appears:

File Directory

This screen lists your files, by number with attached name and also lists the number of bytes of data in
each file.

Press A to Accept and the following screen appears

Memory Information

Cath-Tech™ 49
Hexcorder Millennium II Operation Manual
This screen indicates the number of bytes of memory used in data storage and the number of bytes
available for data storage.

Press A to accept and the Hexcorder returns to the Export Data Menu.

F - Select Survey File

When F is pressed to select file the following screen appears:

Capture Data:

To capture your data in the PC it is necessary to open a capture file:

In Windows Hyper Terminal click on “Transfer” on the upper menu bar then click on “Capture
Text” then enter the drive, directory and file name to be used for your data, when you have entered a
file name, use .TXT or .PRN as the extension then click OK and Windows Hyper Terminal is ready to
capture your data.

50 Cath-Tech™
Hexcorder Millennium II Operation Manual

On the Hexcorder, Press C to change the file number for exporting data, enter the file number to be
exported then press A to accept and the file will be exported to your PC. Note: the Hexcorder
automatically defaults to the last stored file.

When the transfer of data is complete click on Transfer on the Hyper Terminal menu bar then click on
Capture text then select Stop.

This will end your data capture session and store the data on your disk under the file name entered. If
you do not close the capture file by going to Capture text and Stop you may lose date when you exit the
session.

Repeat the above to transfer and capture all of your files.

To exit from the export data function, it is necessary to press the two yellow keys (RESET)
simultaneously.

Cath-Tech™ 51
Hexcorder Millennium II Operation Manual

Datum
The datum exported by the GPS engine can be changed in the Garmin N16 engine to meet the date
requirements of the country in which the unit is being used.

To change the Datum follow the procedures outlined below.

INSTRUCTIONS TO CHANGE GPS DATUM For Garmin GPS16 Engine

EQUIPMENT REQUIRED:

1. HEXCORDER to be altered.
i. The Hexcorder may be either indoors or outdoors for this procedure, i.e. The
GPS need not be locked. The following example was performed indoors.

2. 9PIN TO 9PIN HEXCORDER DOWNLOADING CABLE

3. PC WITH TERMINAL EMULATION PROGRAM INSTALLED and available. serial (COM)

port. E.G. HYPER-TERMINAL, MIRROR, PC-TERM.

INSTRUCTIONS:

Start up the terminal emulator (Hyper Terminal) and set it as follows:

COM1 or COM2 DIRECT or any available COM port, 38400 BAUD, NO

PARITY, 8 BITS, 1 STOP BIT, NO HANDSHAKE, EMULATION: AUTO or
NONE or TTY.

Connect the HEXCORDER to the PC COM port.

PRESS: [0]&[ENTER] TOGETHER power up and reset

Now in Main Menu

PRESS: [5] test

Now in Test Menu

PRESS: [T]&[S] TOGETHER hidden

Now in Test Special Menu

PRESS: [2] GPS

52 Cath-Tech™
Hexcorder Millennium II Operation Manual
Now in Transparent GPS Test Mode. The GPS Engine, (in and out), is connected directly to the
9 pin D RS232 port at the back of the Hexcorder. Output from the GPS engine is also shown on
the Hexcorder display. Strings of characters beginning with $GPGGA should be visible.

The same strings of characters should also be received on the Terminal Emulator. (see example
below):
$GPGGA,161014,4351.5635,N,07942.8229,W,0,00,,,M,,M,,*43
$GPGGA,161015,4351.5635,N,07942.8229,W,0,00,,,M,,M,,*42
$GPGGA,161016,4351.5635,N,07942.8229,W,0,00,,,M,,M,,*41

To change to the SAD1969 (datum # 84)

At the Terminal Emulator enter:

$PGRMC,,,84^M^J
(^M means to press Ctrl and M together)
(^J means to press Ctrl and J together)
the GPS engine should respond with:
$PGRMC,,,84 (which means that the command has been accepted)

Followed by more $GPGGA strings:

$GPGGA,161021,4351.5756,N,07942.7812,W,0,00,,,M,,M,,*4C
$GPGGA,161022,4351.5756,N,07942.7812,W,0,00,,,M,,M,,*4F
$GPGGA,161023,4351.5756,N,07942.7812,W,0,00,,,M,,M,,*4E
$GPGGA,161024,4351.5756,N,07942.7812,W,0,00,,,M,,M,,*49

Note how the 3rd (LAT)field and the fourth (LONG) field have changed in value. This is
because the GPS engine is now using the new datum. The new datum setting is retained by the
GPS engine in non volatile memory and will remain fixed until changed again.

To change back to the WGS84 (default datum # 100)

At the Terminal Emulator enter:

$PGRMC,,,100^M^J
the response should be:
$PGRMC,,,100

The $PGRMCE^M^J command may also be used to check the current settings.

Other Geodetic Datum transformations are available. Please refer to appendix A at the end of this
document

When finished:

PRESS: [0]&[ENTER] TOGETHER to return to normal operation

Now in Main Menu

Cath-Tech™ 53
Hexcorder Millennium II Operation Manual

APPENDIX A

EARTH DATUM’S AVAILABLE:

0 ADINDAN - Ethiopia, Mali, Senegal, Sudan

1 AFGOOYE - Somalia
2 AIN EL ABD 1970 - Bahrain Island, Saudi Arabia
3 ANNA 1 ASTRO 1965 - Cocos Island
4 ARC 1950 - Botswana, Lesotho, Malawi, Swaziland, Zaire, Zambia, Zimbabwe
5 ARC 1960 - Kenya, Tanzania
6 ASCENSION ISLAND 1958 - Ascension Island
7 ASTRO BEACON .E. - Iwo Jima Island
8 AUSTRALIAN GEODETIC 1966 - Australia, Tasmania Island
9 AUSTRALIAN GEODETIC 1984 - Australia, Tasmania Island
10 ASTRO DOS 71/4 - St. Helena Island
11 ASTRONOMIC STATION 1952 - Marcus Island
12 ASTRO B4 SOROL ATOLL - Tern Island
13 BELLEVUE (IGN) - Efate and Erromango Islands
14 BERMUDA 1957 - Bermuda Islands
15 BOGOTA OBSERVATORY - Colombia
16 CAMPO INCHAUSPE - Argentina
17 CANTON ASTRO 1966 - Phoenix Islands
18 CAPE CANAVERAL - Florida, Bahama Islands
19 CAPE - South Africa
20 CARTHAGE - Tunisia
21 CHATHAM 1971 - Chatham Island (New Zealand)
22 CHUA ASTRO - Paraguay
23 CORREGO ALEGRE - Brazil
24 DJAKARTA (BATAVIA) - Sumatra Island (Indonesia)
25 DOS 1968 - Gizo Island (New Georgia Islands)
26 EASTER ISLAND 1967 - Easter Island
27 EUROPEAN 1950 - Austria, Belgium, Denmark, Finland, France, Germany, Gibraltar, Greece,
Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland
28 EUROPEAN 1979 - Austria, Finland, Netherlands, Norway, Spain, Sweden, Switzerland
29 FINLAND HAYFORD 1910 - Finland
30 GANDAJIKA BASE - Republic of Maldives
31 GEODETIC DATUM 1949 - New Zealand
32 ORDNANCE SURVEY OF GREAT BRITAIN 1936 - England, Isle of Man, Scotland, Shetland
Islands, Wales
33 GUAM 1963 - Guam Island
34 GUX 1 ASTRO - Guadalcanal Island
35 HJORSEY 1955 - Iceland
36 HONG KONG 1963 - Hong Kong
37 INDIAN - Bangladesh, India, Nepal
38 INDIAN - Thailand, Vietnam
39 IRELAND 1965 - Ireland
40 ISTS O73 ASTRO 1969 - Diego Garcia
41 JOHNSTON ISLAND 1961 - Johnston Island

54 Cath-Tech™
Hexcorder Millennium II Operation Manual
42 KANDAWALA - Sri Lanka
43 KERGUELEN ISLAND - Kerguelen Island
44 KERTAU 1948 - West Malaysia, Singapore
45 L.C. 5 ASTRO - Cayman Brac Island
46 LIBERIA 1964 - Liberia
47 LUZON - Mindanao Island
48 LUZON - Phillippines (excluding Mindanao Island)
49 MAHE 1971 - Mahe Island
50 MARCO ASTRO - Salvage Islands
51 MASSAWA - Eritrea (Ethiopia)
52 MERCHICH - Morocco
53 MIDWAY ASTRO 1961 - Midway Island
54 MINNA - Nigeria
55 NORTH AMERICAN 1927 - Alaska
56 NORTH AMERICAN 1927 - Bahamas (excluding San Salvador Island)
57 NORTH AMERICAN 1927 - Central America (Belize, Costa Rica, El Salvador, Guatemala,
Honduras, Nicaragua)
58 NORTH AMERICAN 1927 - Canal Zone
59 NORTH AMERICAN 1927 - Canada (including Newfoundland Island)
60 NORTH AMERICAN 1927 - Caribbean (Barbados, Caicos Islands, Cuba, Dominican Republic,
Grand Cayman, Jamaica, Leeward Islands, Turks Islands)
61 NORTH AMERICAN 1927 - Mean Value (CONUS)
62 NORTH AMERICAN 1927 - Cuba
63 NORTH AMERICAN 1927 - Greenland (Hayes Peninsula)
64 NORTH AMERICAN 1927 - Mexico
65 NORTH AMERICAN 1927 - San Salvador Island
66 NORTH AMERICAN 1983 - Alaska, Canada, Central America, CONUS, Mexico
67 NAPARIMA, BWI - Trinidad and Tobago
68 NAHRWAN - Masirah Island (Oman)
69 NAHRWAN - Saudi Arabia
70 NAHRWAN - United Arab Emirates
71 OBSERVATORIO 1966 - Corvo and Flores Islands (Azores)
72 OLD EGYPTIAN - Egypt
73 OLD HAWAIIAN - Mean Value
74 OMAN - Oman
75 PICO DE LAS NIEVES - Canary Islands
76 PITCAIRN ASTRO 1967 - Pitcairn Island
77 PUERTO RICO - Puerto Rico, Virgin Islands
78 QATAR NATIONAL - Qatar
79 QORNOQ - South Greenland
80 REUNION - Mascarene Island
81 ROME 1940 - Sardinia Island
82 RT 90 - Sweden
83 PROVISIONAL SOUTH AMERICAN 1956 - Bolivia, Chile, Colombia, Ecuador, Guyana, Peru,
Venezuela
84 SOUTH AMERICAN 1969 - Argentina, Bolivia, Brazil, Chile, Colombia, Ecuador, Guyana,
Paraguay, Peru, Venezuela, Trinidad and Tobago
85 SOUTH ASIA - Singapore
86 PROVISIONAL SOUTH CHILEAN 1963 - South Chile
Cath-Tech™ 55
Hexcorder Millennium II Operation Manual
87 SANTO (DOS) - Espirito Santo Island
88 SAO BRAZ - Sao Miguel, Santa Maria Islands (Azores)
89 SAPPER HILL 1943 - East Falkland Island
90 SCHWARZECK - Namibia
91 SOUTHEAST BASE - Porto Santo and Madeira Islands
92 SOUTHWEST BASE - Faial, Graciosa, Pico, Sao Jorge, and Terceira Islands (Azores)
93 TIMBALAI 1948 - Brunei and East Malaysia (Sarawak and Sabah)
94 TOKYO - Japan, Korea, Okinawa
95 TRISTAN ASTRO 1968 - Tristan da Cunha
96 User defined earth datum
97 VITI LEVU 1916 - Viti Levu Island (Fiji Islands)
98 WAKE-ENIWETOK 1960 - Marshall Islands
99 WORLD GEODETIC SYSTEM 1972
100 WORLD GEODETIC SYSTEM 1984
101 ZANDERIJ - Surinam
102 CH-1903 - Switzerland
103 Hu - Tzu - Shan
104 Indonesia 74
105 Austria
106 Potsdam
107 Taiwan - modified Hu-Tzu-Shan
108 GDA - Geocentric Datum of Australia
109 Dutch

56 Cath-Tech™
Hexcorder Millennium II Operation Manual

Survey Technique

Close Interval Potential Surveys (CIPS)

GPS synchronized close interval surveys yields the most accurate over the line PRO-ACTIVE corrosion
control survey. A properly executed CIPS survey will indicate all areas of inadequate cathodic
protection current. The Hexcorder correlates the rectifier ON and Instant OFF potentials with distance,
time, elevation and GPS coordinates.

Areas of sub-criterion potentials are easily traceable by chainage and GPS coordinates. The survey
should use both half-cell sticks and keep on a half-cell in contact with the ground at all times to
minimize delay while the half cell stabilizes. In areas where the ground id dry, it may be necessary to
wet the ground to reduce half-cell to soil contact resistance.

A close interval survey is best accomplished at a comfortable walking speed, most surveyors prefer a 1
second cycle whereby the rectifier is turned OFF for 200 to 300 milliseconds every second. The one-
second cycle will yield a stored reading approximately every two metres at a comfortable walking
speed.

To take and store a reading, observe the potential on the Hexcorder display then when you have a valid
pipe-to-soil potential press one of the buttons on the half-cell stick sharply. Make sure that the half-cell
stays firmly in contact with the soil until the Hexcorder beeps indicating the reading is stored. When
using a 1 second cycle the pipe-to-soil potential can only be updated one per second. The Hexcorder
reads the rectifier OFF potential first then the rectifier ON potential. These values along with the
chainage and GPS coordinates are written to the display every second.

Cath-Tech™ 57
Hexcorder Millennium II Operation Manual
What you see is what you get, when the button is depressed to record the pipe-to-soil potential, what is
on the display is written to memory. Make sure one half cell is firmly in contact with the soil when the
button is pressed to store a reading.

Graph of CIPS Survey

2 4 " P i pe l i ne

1600

1400

1200

1000

800

600

T
400
M N
200 a P
n
I
0 i

C h a i n a g e me t r e s

r ec t on r ec t of f Cr i t er i on

The stored survey results can be plotted using Windows Excel or other spared sheet or graphing
program.

58 Cath-Tech™
Hexcorder Millennium II Operation Manual

DCVG Surveys
DCVG surveys can be undertaken with or without pipe connection. If done with a pipe connection,
both the close interval potential (CIPS) survey data and the direct current voltage gradient (DCVG) can
be gathered simultaneously.

A combined CIPS + DCVG survey provides the corrosion engineer with accurate information on the
level of cathodic protection on the pipeline as well as coating defects.

Prior to commencement of any survey section, current interrupter(s) are installed in the existing
cathodic protection rectifiers or a temporary rectifier is installed to provide pulsed DC current to the
pipeline under test. If more than one rectifier is involved in the area to be surveyed using DCVG
techniques, then the interrupters shall be synchronized by the GPS system.

CIPS + DCVG with a Pipe Connection

CIPS + DCVG
-4000

-3500

Defect
-3000

-2500
Potential Millivolts

-2000

-1500

-1000

-500

500

1000
4

11.8

15.2

17.8

21.8

27.2

29.9

33.6

37.6

41.5

46

51.3

55.3

59.6

65.2

71.1

76.8

79.5

83.6

87.1

89.5

94.7

99.2

105

110

116

122

127

130

Chainage Metres

rect on rect off Criterion Gradient

Cath-Tech™ 59
Hexcorder Millennium II Operation Manual

DCVG no Pipe Connection

To undertake a DCVG survey typically, a minimum potential swing of 300-500 mV is sought and the
current source output of the rectifiers is adjusted accordingly. The application of a pulsed current
enables coating defects to be distinguished from potential differences between the half-cells.

The difference between 'on' and 'off' potentials is recorded at the test point nearest the survey start point,
and all other test points encountered, and the survey commenced.
The operator traverses the pipeline route using the probes as walking sticks. One probe is in contact
with the ground at all times and for a short duration between strides both probes must be in ground
contact. One probe can be on the centerline of the pipeline and the other maintained at a lateral
separation of 1-2 m or probes can leap-frog along the centre line.

If no defects are present the needle on the voltmeter registers no movement.

As a defect is approached a noticeable fluctuation is observed on the voltmeter at a rate similar to the
interruption cycle. The amplitude of the fluctuation increases as the defect is approached and
adjustment of voltmeter sensitivity is made as necessary. The swing on the voltmeter is directional,
providing the probes are maintained in similar orientation parallel to the pipeline.

Thus, the defect is centered by detailed maneuver around the epicenter and the size of the defect
estimated by considering signal strength at the defect, difference between 'on' and 'off' potential at
adjacent test point and the distance from those points.
Data obtained

The DCVG survey provides an evaluation of each defect located. The defect can be sized by relating the
signal voltage (or potential swing) to remote earth (mV1) to the signal voltage (potential swing)
recorded at the nearest two test post (mV2,, mV3). The distances of defect to these two test posts (m1,
m2) are also brought in account. In addition, it is also possible to determine whether active corrosion is
taking place at the defect.

60 Cath-Tech™
Hexcorder Millennium II Operation Manual

D C VG

300
DE FE C

250

200

150

100

50

0
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28

-50

DCVG Gradient Patterns

DCVG Calculations
Coating defects are recorded on defect sheets with reference to a fixed point marked on (route)
alignment sheets and/or a stake placed in the ground. The following formula assumes uniform soil
resistivity and cathodic protection current attenuation.
Comments on signal strength should be recorded and the defect graded, where:
mV1
%IR = ------------------------------------------------
mV2 - (m1/(m1+m2)*(mV2-mV3))
mV1 = Voltage swing at pipe
mV2 = Voltage swing at last test station
mV3 = Voltage swing at next test station
m1 = Distance to last test station
m2 = Distance to next test station

Cath-Tech™ 61
Hexcorder Millennium II Operation Manual

Cathodic Protection and Coating Defects

All coating defects that exhibit potentials below the criterion for protection require attention.
Adjustments or upgrading of the cathodic protection system are indicated at all locations where the
pipe-to-soil potential is sub criterion. Repairing holidays or defects in the coating can result in
accelerated corrosion if adequate levels of cathodic protection are not maintained. Significant
improvements or upgrading of a cathodic protection system can be performed for the cost of one
excavation to repair a coating defect or holiday. The application and maintenance of an adequate
cathodic protection system is a proactive method of corrosion control unlike internal inspections, which
are reactive corrosion control, whereby excavation and repair or replacement is made to corrosion
damaged pipe.

62 Cath-Tech™