The Centurion 7 “Sourcing” Reset Circuit

Featuring the Telemechanique Preventa XPS-At Safety relay

In 2006 Milltronics changed from a “Sinking” interface panel which used 0VDC inputs and
outputs to a “Sourcing” interface which uses 24VDC inputs and outputs. The machine enable or “reset”
circuit was changed at this time to make use of the Telemecanique Preventa XPS-AT Safety Relay. The
following information describes this Safety Relay and its use in a typical Milltronics machine.

A1 S12 S22 13 23 33 41 57 67

B1 S11 S21

Tele mecanique >>PREVENTA<<

TYPE XPS - AT

A1 /A2 8
Fu se 6 10
Inp ut A 4 12
S 12
2 20
Inp ut B
S 22 1 25
Out put 0.5 0 30
St op Time [s]
1

Y3 Y4 Y5

A2 14 24 34 42 58 68 S33 Y1 Y2

Safety Relay Terminal Designations

A1 - 24 volts DC power
A2 – DC ground

Y3,Y4,Y5 – Jumper to indicate the nature of the reset signal. Y3 and Y5 are tied together in a
Milltronics machine indicating that the Safety Relay will reset on the trailing edge of the reset pulse.
This means that reset occurs upon button release, not when it is first pressed.

S11 to S12 – Input Circuit A

S21 to S22 – Input circuit B
Input circuits that indicate the machine status outside of the Safety Relay is OK. Circuits must
be unbroken to allow the machine to reset. A break in either circuit will signal the Safety Relay to stop
the machine. If the relay is faulted both circuits must be broken (an e-stop button pressed) before they
can be restored.

B1 to S11 – These terminals are jumped to indicate the presence of two separate input circuits (A and
B). When this jumper is in place the two circuits are operated at different voltages (one at 24vdc and the
other at 0vdc). This allows the Safety Relay to detect shorts between the two circuits or to ground.

S33 to Y2 – A momentary connection between these two terminals initiates the reset of the Safety
Relay. The connection can be broken down into two parts:

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 S33 to Y1 – The reset pulse. This includes a contact in the reset button and a relay contact in the
interface panel tied to the “ALLOW RESET” signal (J3-9). There should be continuity between
these two terminals when the reset button is pressed.

Y1 to Y2 – Pre-existing conditions. These are normally closed contacts on any number of relays
activated by the Safety Relay that should be OFF before the machine is allowed to reset. In most
Milltronics machines this includes the relays that provide power to the axes and spindle
controllers. Other relay contacts could be present as well (see specific machine print for details).

The Y1 terminal does not have an internal connection to the Safety Relay and is used only as a
convenient terminal to separate the wiring between the reset pulse and NC contact circuits.

41 to 42 – This is an NC contact that is used to alert the CNC that the Safety Relay is in a stopped
condition. This signal is connected to the E-stop input (J1-1) of the CNC.

13 to 14
23 to 24
33 to 34 – These normally open contacts close when the Safety Relay is enabled. They open
immediately when the relay is stopped.

57 to 58
67 to 68 - These normally open contacts close when the Safety Relay is enabled. They open a delayed
time after the relay is stopped. The duration of the delay (in seconds) is set by the dial on the front of
the Safety Relay.

Safety Relay Conditions at Start

The following conditions should exist on the Safety Relay once the CNC control has booted up and the
emergency stop buttons are released. The machine will not be prepared to reset if these conditions are
not met.

Power on A1 and A2. Indicated by top light “A1/A2 Fuse” being lit.
Continutity in the circuit between S11 and S12 terminals indicated by “Input A” light being on
Continutity in the circuit between S21 and S22 terminals indicated by “Input B” light being on
Stop 1 time delay circuits are open indicated by the “Output Stop 1” light being off.

Any problems in the initial startup of the relay could due to any of the following causes.

If the “A1/A2 Fuse” light is not on:

 The relay is not getting 24vdc to the A1 terminal.

 It is not connected to DC ground at terminal A2.

 The Safety Relay is defective.

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If the “Input A” and “Input B” lights are both out:

 One of the e-stop buttons is depressed.

 An external device with an emergency stop button on it is not connected, i.e. remote hand wheel
or chip conveyor.

If the “Input B” light is on, but the “Input A” light is not. There is a break between S11 and S12
caused by:

 The Watchdog relay in the interface panel not being on (check interface).

 The CR1A “Software E-Stop” relay being on or contacts stuck open (check output J3-1 or the
CR1A relay).

 A break in E-stop wiring between S11 and S12. Check for continuity thru the circuit.

The “Input A” light is on, but the “Input B” light is not. There is a break between S21 and S22
caused by:

 A break in E-stop wiring between S21 and S22. Check for continuity thru the circuit.

 On initial applications where CR1A contacts and watchdog contacts were wired between
terminal B1 and S11 on the Safety Relay (Disregard if there is a jumper directly from B1 to S11)
o Watchdog relay in the interface panel not being on (check interface)
o CR1A “Software E-Stop” relay being on or contacts stuck open (check output J3-1)

If the “Output Stop 1” light is on:

 The machine is already reset.

 The relay is in the time delay period after e-stop.

 The relay is defective.

Resetting the Machine

How to reset the machine:

 Release all of the emergency stop switches on the machine. A1/A2 Fuse, Input A, and Input B
lights should now all be lit.

 Wait approximately 5 seconds.

 Press and RELEASE the RESET button on the machine. Machine should reset after the release
of the reset button.

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How to reset the machine after a software emergency stop (drive fault, excess error, air pressure
alarm):

 Clear the cause of the machine fault.

 Press any one of the emergency stop buttons (to clear both A and B emergency stop channels).

 Release all of the emergency stop switches on the machine. A1/A2 Fuse, Input A, and Input B
lights should now all be lit.

 Wait approximately 5 seconds.

 Press and RELEASE the reset button on the machine.

 Machine should reset after the release of the e-stop button.

The Reset Sequence Explained

When the machine is powered on the A1/A2 Fuse light should come on. The input B light will come on
as well.

As the interface panel initializes and the watchdog relay turns on, the Input A light will come on.

The relay should now be in its starting condition and prepared to be enabled. If it is not see the above
section “Safety Relay conditions at start” to determine why.

To enable the machine, press the reset button. A signal is sent from terminal S33 on the Safety Relay
through a “reset allow” relay contact in the interface assembly, then through an NO contact on the reset
button itself to terminal Y1 on the Safety Relay. This signal then travels from The Y1 terminal through
various NC contacts (see appropriate machine schematic for details) to the Y2 terminal. The button is
then released, stopping the signal. It is this “trailing edge” when the signal stops that is an indication
that the Safety Relay is to enable. If the relay is enabled the fourth light “Output Stop 1” should come
on.

Things to check if the Safety Relay does not enable:

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Make sure that the lights show that the relay is in the starting condition.

Check that the signal is traveling between S33 and Y1.

 The “Allow reset” contact may not be closing in the interface when the reset button is pressed.
Check in the diagnostic screen for J3-9 to be changing to a white dot when the reset button is
pressed. If it does not the CNC does not want the machine to reset. Things that inhibit the
“Allow Reset”:

o J1-1 “E-stopped” is a black dot. This input is triggered through the NC contact at
terminals 41 and 42 of the Safety Relay. If the machine does not know it is e-stopped,
then it will not try to reset.

o Spindle drive fault.

o Watchdog failure in the interface assembly (Input A light should not be lit).

 Check that there is continuity through the allow reset contact between J3-45 and J3-46 on the
interface terminals when reset is pressed. If the diagnostic dot changes color, but there is no
continuity between the two terminals, the interface panel may be bad.

 Check that there is continuity through the reset button contacts when reset is pressed. If there is
no continuity through it when pressed then the button or wiring may be bad.

 Check that the signal is traveling between Y1 and Y2.

Prior to the Safety Relay being enabled the relay contacts should be closed between Y1 and
Y2. Check for continuity between Y1 and Y2 terminals. If there is no continuity a relay or
contact may be stuck open.

 Check if there is always continuity between S33 and Y2

This would require a multi-level failure, however if the cycle start was stuck on there could
be continuity between S33 and Y2 all of the time. In that case there would be no “trailing
edge” signal when the button was released and the Safety Relay will not enable.

 The Safety Relay is bad.

If the Safety Relay energizes for a second, but drops out immediately then one of the “Drive OK”
signals may be missing which would indicate a drive fault. Check for A 449 alarm on the control or
look for fault indications on the axis drives.

The safety relay is highly reliable and its failure is unlikely. If relay failure is suspected, recheck the
above conditions prior to replacing it.

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Sourcing Machine Reset Basic Diagram

Milltronics CNC
Safety Relay Circuit
Basic Diagram
One or more NC contacts connected
to various devices in the machine
See individual machine print for details

J1-1
E-STOPPED
INPUT

EMERGENCY STOP BUTTONS

Dual contacts break both channels
CR1A RELAY
SOFTWARE E-STOP
J3-41

INTERNAL
WATCHDOG

J3-42

+24 VDC

12
N.C. CONTACT
Open Upon Reset
Closes Immediately
Upon E-Stop
A1 B1 S11 S21 S22 S12 13 23 33 41 57 67
Milltronics Y3
"ACTIVE HIGH" Y4 XPS-AT SAFETY RELAY
Interface panel Y5
A2 S33 Y1 Y2 14 24 34 42 58 68
N.O. CONTACTS N.O. CONTACTS
Close upon Reset Close upon Reset
Open immediately Open a delayed time
22 upon E-stop after E-stop
DC Ground 12

+24 VDC
J3-45

ALLOW N.C. CONTACTS

RESET from relays that are
J3-46 to be OFF before reset
Front Panel is allowed.
Reset Button

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 The Centurion 7 “Sinking” Reset Circuit
E-Stop
CR29 Over Travel Limits
Allow Reset X OUT 9 CR1C 6 7 8 9 12 +24VDC

RESET
CR1C CR1A
DC Ground 22

FPP 11 Watchdog MISC 11

DC Ground 22 CR29 12 +24VDC

K1 X IN 1
DC Ground 22 CR1A Internal +24 VDC

Control E-Stop
X OUT 1
(Internal)

MISC 2 CR1C MISC 1

DC Ground 22 K1 12 +24VDC

1. The front panel reset switch is pressed, sending a keyboard signal to the control

2. Axis 1-Output 9 “ALLOW RESET” will turn on while the button is pressed, providing a
momentary ground to the circuit. This is indicated on the diagnostics screen ([F6] Display, [F4] Diag)
by the dot next to axis 1-Out 9 turning from black to white

If Axis 1-Output 9 does not turn to a white dot while the reset button is pressed there are several
possible problems:

 There may be a drive fault inhibiting the reset signal. This would be signified by a white dot
at Axis 1-Input 9 if it is the spindle drive. An axis drive fault will show up in Axis 4
diagnostic group. Axis 4 inputs 1 through 5 could possibly be drive indicators, depending
upon the number of axis. If the machine is equipped with D.C. drives, these will be drive
faults and a white dot will indicate that a drive is faulted. If the machine has A.C. Yaskawa
drives these will be drive O.K. indicators and a fault will be shown by a black dot (a white
dot means the drive is o.k.)

 There must be a ground at Axis 1-Input 1 “E-Stopped” for the machine to be able to set the
“ALLOW RESET”. If Axis 1-Input 1 is not a white dot, it is missing that ground. The
+24vdc line may be low or shorted and its voltage should be checked. The ground comes
through normally closed contacts on the K1 machine reset relay. There may be a problem
with it.

 The reset switch itself may be malfunctioning. Plug in an external keyboard and press the
F10 key while holding down the Alt key. This will simulate the keyboard signal that the
reset switch sends when depressed. If the machine resets this way the switch needs to be
replaced.

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3. The internal ground at Axis 1-Output 9 energizes the coil of CR 1C through contacts on the CR
29 relay, the normally closed contacts of the E-Stop button and through the over travel limits or the
normally open contacts of the reset button.

If CR 1C is not energized at this time there are again several possibilities:

 The CR 29 relay is not activated. Check the LED next to the CR 29 relay located on a quad
relay card (the relay itself should be labeled). If the LED is unlit there may be a problem in
the control. The CR 29 relay is powered through the control watchdog relay. Check LED 1
on the control’s interface panel. If it is unlit there is a malfunction in the control and it may
have to be sent in for repair.

 The E-Stop switch contact is malfunctioning such that it is open all of the time.

 The CR 1C relay has failed.

 There may be a problem in the jumper settings if the interface panel has just been replaced.

4. When the CR 1C relay energizes, the relay latches to ground through the over travel limits,
through its own contacts, and through a set of normally closed contacts on the CR 1A relay. (The CR
1A is wired through normally closed contacts on K 1, and will shut off when K 1 comes on. It is also
wired to the normally open E-Stop contacts and will come on when E-stop is latched or held in.) The
reset switch is then released leaving the CR 1C on.

If CR 1C will not remain latched there are several possible problems:

 The machine is sitting on a limit switch or a limit wire is broke. Hold down the reset switch
and jog the machine to the center of travel. Release the reset and observe if the machine
stays in reset. If a break in the limits is suspected they may be jumped across by placing a
jumper wire from terminal block 6 to block 9. If the machine stays reset the problem axis
can be isolated by jumping across terminal blocks 6 to 7 (X axis), blocks 7 to 8 (Y axis), and
blocks 8 to 9 (Z axis).

 The E-stop button may still be latched or the normally open contacts may be stuck shut
leaving the CR 1A relay energized.

 The K 1 relay contacts may be stuck shut or K1 is not coming on, causing the same condition
as above.

 There may be problems with the contacts on CR 1A or CR 1C.

DO NOT OPERATE MACHINE WITH ANY JUMPERS IN PLACE. Jumpers are for
trouble shooting purposes only.

5. With CR 1C latched the K 1 machine reset relay should then come on and all machine devices
will be energized.

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 CMOS Setting
The CMOS of the control, sometimes referred to as the Bios settings, is the memory on the
motherboard where the configuration of the motherboard itself is set. It is here that the hardware
devices such as floppy and hard disk drives are indicated. The BIOS also keeps the date and time, boot
sequence, and many other settings. The addition of new hardware, or a battery failure on the
motherboard will require entry and setting of the CMOS.

CMOS Setup for SBC 9732 board in a Centurion 7 Control

To access and make changes to the CMOS an external keyboard must be plugged into the machine. The
proper keys will not be available without it.

To enter the CMOS:

Turn on the machine power and immediately begin pressing the DELETE key on the external keyboard.
Do not hold the key down as it will cause a Keyboard error.

If successful a blue screen will appear labeled “CMOS Setup Utility – Copyright © 1984-2001 Award
Software.” The following menu selections will appear:

Standard CMOS Features PC Health Status

Advanced BIOS Features Frequency/Voltage Control
Advanced Chipset Features Load Optimized Defaults
Intergrated Peripherals Set Password
Power Management Setup Save and Exit Setup
PnP/PCI Configurations Exit without saving

The bottom of the screen will list the keys used to navigate the CMOS setup software.

To set the CMOS for a Centurion 7 Control:

Use the arrow keys to move the cursor to Load Optimized Defaults. Press ENTER.
A dialog box will appear that says “Load optimized defaults (Y/N)”. Enter Y for yes, then press
ENTER. Default CMOS settings will be loaded.

Use the arrow keys to move the cursor to Standard CMOS Features. Press ENTER.
Move the cursor to “IDE Primary Slave”. Press ENTER.
Move the cursor to “IDE Primary Slave”. Change the setting to NONE using the PAGE UP key.
Press ESC to return to the Standard CMOS Features menu.
Press ESC to return to the Main CMOS menu.

Use the arrow keys to move the cursor to Advanced Bios Features. Press ENTER.
Move the cursor to “Boot Numlock Status”. Change the setting to OFF using the PAGE UP key.
Press ESC to return to the Main CMOS menu.

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Use the arrow keys to move the cursor to Advanced Chipset Features. Press ENTER.
Move the cursor to “Panel Type”. Change the setting to the appropriate value for the panel type.
Move the cursor to “On Chip USB”. Change the setting to DISABLED using the PAGE UP key.
Press ESC to return to the Main CMOS menu.
Panel type - 12" - 800x600 18 bit - 10" - 800x600 LVDS.

Use the arrow keys to move the cursor to Integrated Peripherals. Press ENTER.
Move the cursor to “Onboard Parallel Port”. Change the setting to DISABLED using the PAGE
UP key.

Press the F10 SAVE Key. A dialog box will prompt “Save to CMOS and EXIT (Y/N)”. Enter Y for
yes, then press ENTER. The CMOS setting is complete.

The control will reboot and should come up as normal.

CMOS Setup for SBC 9550 board

If a Centurion 7 control with a PCM9550 single board shows a screen with only bands of gray, black,
and blue color but the machine operates otherwise then the CMOS battery has failed. The battery must
be replaced (see board illustrations for location) and the cmos settings restored.

Restoring the CMOS will require an external VGA monitor to be plugged into the motherboard. A
ribbon cable should be plugged into the CN1 connector on the single board with a VGA video connector
on the opposite end. If the ribbon cable is not present then one must be obtained from the parts
department (Part number CB-75).

Connect the external monitor and an external keyboard and enter the CMOS in the same manner as for
the PCM 9732 board.

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 Setting up custom codes on the Centurion Control
Often it is desirable or necessary to create a user defined M-code or G-Code for the machine to
use. A custom code is one that is linked to a program such that when the M-code or G-code is
commanded, the program will be run. The procedure to set up a custom code follows.

1. From the main menu, enter the setup parameters and go to the Power group.

2. Page down to the custom M and G code section. Select the custom code slot that is to be used
and set it to the M or G Code number desired (if an M 77 is being created, set the custom M-
code to 77). Escape back to the main menu.

3. Write a program with the number of the custom M-code slot that was selected. If custom M-
code O9020 was set, then the program written must be named O9020. Save the program.

4. Escape to the main menu, E-stop, and power down the machine. Wait approximately 30 seconds
and power up.

5. When the machine is powered back up the M-code should be active.

Note: If an M-code number of an existing M-code is used, the custom code will replace the
original. If the original code is called at the end of the custom code the original will be executed after
the custom events are run. A custom M-code cannot call another custom M-code. Custom M-codes can
be placed either in the parts storage or the B:/ram. If they are placed in ram they can be saved with the
other parameters and are safe from being erased.

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Sample Custom M-Code
Example: To make a lamp come on when an M30 is commanded.

1. Start a new text program o9024. In the program write:

SET Z8
M30

2. Store the program.

3. Then set the Parameter Custom M code 9024 to 30. (see below)

4. After this has been done reboot the machine to load the program into main memory.

When the M30 command is commanded, 9024 gets run. The SET Z8 command will trigger Z output 8,
which could turn on a relay wired to it. This in turn could power a light. The original M30 will then be
executed and the command is complete.

Wait Channel
Input J1-7 (Axis 1-input 7) is the wait channel. It is wired to terminal block 79.

If an M32 is commanded in a program the control will look at this input. If the input is signaled,
showing a white dot in diagnostics display, the machine will stop at this point and wait for the input to
lose the signal before continuing the program. If the signal is not there at the time the M32 is issued the
control will continue as if it did not receive the code at all. The signal must only be broken for an
instant to allow the control to pass beyond this block of the program.

A popular use for the wait command is if the machine tool has an indexer installed. The indexer
code will usually include a check of the wait channel. The indexer itself will have a channel wired to
the wait channel that will signal while the indexer is turning. When the indexer move is completed it
will break the signal and allow the program to continue.

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RS 232 Communication
Another method of bringing information in from the outside world to the control's memory, other
than the floppy drive, is the RS232 port. Centurion CNC controls use a standard RS232 interface just as
that found on today’s desktop personal computers.

The pinout of the 25 pin “D” style connector on the control box is as follows:
 Pin 2 Receive data
 Pin 3 Transmit data
 Pin 7 Signal Ground
 Pin 1 Frame Ground – (tied to cable shield on one computer end only)

Operation notes.
 The Milltronics end requires no jumpers such as 5,6,8, & 20. Only pins 2,3, & 7 are used.

 Hardware handshaking signals are NOT used.

 Software handshaking (Xon & Xoff) is used to control the data flow. This handshaking mode is
employed by default and cannot be disabled.

 The required parameters for baud rate, data bits, stop bits, and parity are found under PARAMS-
CTRL in the CNC menus. Before attempting any communication ensure that the devices on both
ends are set up the same way as one another.

 When transferring data always prepare the receiving end first, then initiate the sender.

 Always make sure the type of file being received is the same type as that being sent. When
transferring files from a CAD/CAM system the file type will always be TEXT.

 To receive a file, go into UTIL-RS232-RECV, select the type of the file TEXT or FCAM. Type the
name or number of the new file being created, then press enter. The file name of the file being sent
is not transferred with the data so the name must be specified when RECEIVE FILE is initiated.

 To send a file go into UTIL-RS232-SEND, select the type of file TEXT or CONV, & MENU. Then
from the menu, select the file with the cursor arrow, hit enter, then F1 to begin.

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RS232 Cables
There are two different cable configurations used for RS232 communications. The two drawings
below show how these cables should be made for proper communication to the machine. The machine
end of both cables requires a male 25-pin plug. The computer end of the cable is determined by the type
of port used.

In making a 25 pin to 25-pin cable, connect pin 1 of the computer end only to the shield of the
cable. Pin 2 on the computer end should connect to pin 3 of the machine end. Pin 3 of the computer end
should connect to pin 2 of the machine end. Pin 7 of the computer end should connect to pin 7 on the
machine end as a ground.

In making a 9 pin to 25-pin cable, as before pin 1 on the 9-pin computer end should be connected
to the cable shield. Pin 2 on the computer end should connect to pin 2 on the machine end. Pin 3 on the
computer end should connect to pin 3 on the machine end. And pin 5 on the computer end should
connect to pin 7 on the machine end as signal ground.

25 Pin to 25 Pin Cable

Computer Machine
25 Pin Female 25 Pin Male
To Cable Shield
Pin 1

Pin 2 Pin 2

Pin 3 Pin 3

Pin 7 Pin 7

9 Pin to 25 Pin
Computer
9 Pin Female Machine
25 Pin Male
To Cable Shield
Pin 1

Pin 2 Pin 2

Pin 3 Pin 3

Pin 5
Pin 7

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