Product Specification 03423 

(Revision C, 2/2017) 

505XT Digital Control 
for Steam Turbines 

Applications   Field-configurable
The 505XT controller is designed to operate single valve,  Integrated graphical
or single extraction/admission industrial steam turbines operator control
of all sizes and applications. This steam turbine
controller includes specifically designed algorithms and
panel
logic to start, stop, control, and protect industrial steam
turbines or turbo-expanders, driving generators,
 Automatic start
compressors, pumps, or industrial fans. routines
The 505XT control’s unique PID structure makes it ideal  Integrated first-out
for applications where it is required to control steam plant
parameters like turbine speed, turbine load, turbine
problem indicator
extraction header pressure, turbine inlet header pressure,
exhaust header pressure, or tie-line power.
 Trip and Alarm
event recorder
The control’s special PID-to-PID logic allows stable control during normal turbine operation
and bumpless control mode transfers during plant upsets, minimizing process over or  Ext/Adm
undershoot conditions. The 505XT controller senses turbine speed via passive or active
speed probes and controls the steam turbine through one or two (split-range) actuators Decoupling
connected to the turbine inlet steam valves.
 User-friendly menu
When configured to control single extraction and or admission based steam turbines, format
Woodward’s field-proven ratio-limiter function ensures that interaction between the two
controlled parameters (i.e., speed & extraction or inlet header & extraction) is correctly  Multi-Lingual
decoupled. Simply by entering maximum levels and three points from the turbine’s steam map
(operating envelope), the 505 automatically calculates all the PID-to-valve ratios and all  Ext/Adm Map
turbine operation and protection limits.
Display Screen
The 505XT controller also includes the following turbine protection functions to ensure that the
turbine or its driven load (compressor, pump, generator) is not operated outside of its  OPTI TUNE PID
designed limits: controllers
 3 Critical speed avoidance bands
 Overspeed anticipation and shutdown protection  Real-time clock
 Configurable under- or over-pressure shutdown logic
 Minimum and maximum speed and load settings
synchronization via
 Maximum low pressure stage overpressure limits SNTP
 Minimum high pressure stage flow limits
 Ethernet
Ethernet and serial communications allow users to easily connect the 505XT into the plant or
process control system. All controller inputs, outputs, and statuses can be monitored and all
communications
start/stop or enable/disable commands can be given through industry standard Modbus® *  Same form-fit-
TCP or OPC protocols. The 505XT uses SNTP (synchronized network time protocol) over
Ethernet to allow users to synchronize the 505XT’s real-time clock to the plant distributed function as previous
control system. 505E versions
* Modbus is a trademark of Schneider Automation Inc.
 Sulfur-resistant
Description  conformal coating
The 505XT control is packaged in an industrial hardened enclosure designed to be mounted  Certified for
within a system control panel located in a plant control room or next to the turbine. The
control’s front panel serves as both a programming station and operator control panel (OCP). Hazardous
This user-friendly front panel allows engineers to access and program the unit to the specific Locations
plant’s requirements, and plant operators to easily start/stop the turbine and enable/disable
any control mode. Password security protects all unit program mode settings. The controller’s
8.4-inch (21.3 cm) graphical display allows operators to view actual and setpoint values from
the same screen, simplifying turbine operation.
 Woodward 03423a p.2
Once configured, the 505XT performs a configuration check
Turbine interface input and output wiring access is located on routine to ensure that the programmer did not make any basic
the controller’s lower back panel. Un-pluggable terminal configuration mistakes.
blocks allow for easy system installation, troubleshooting, and
replacement. Optionally, users can increase the number of Optionally, users can utilize Woodward’s RemoteView
input and output signals to/from the 505 by connecting pre- software program with the 505XT to function as a remote
programmed LINKnet HT™ distributed I/O nodes to the operator control panel and/or engineering station. Once
505XT’s CAN communication ports. The design of these loaded onto a remote computer or touch panel, this software
special distributed I/O modules allows for flexibility of program allows the computer or touch panel to perform all of
mounting by the turbine or by the controller, depending on the 505XT front panel display functions (monitor, operate,
customer’s preference. The following additional I/O signals tune, and configure). Password-based login level security
can be connected to the 505XT via CAN communications: allows users to manage which functions they want the remote
 16 4–20 mA input channels and 4 4–20 mA output panel user to have. Refer to product specification 03424 for
channels (via 2 LINKnet HT AIO modules) more information on RemoteView’s capabilities.
 8 RTD signals (via 1 LINKnet HT RTD module)
The 505XT also includes a suite of service tools to allow users
 16 Discrete inputs (via 1 LINKnet HT DI module) to perform the following functions:
 16 Relay output drivers (via 1 LINKnet HT DO module)  Download configuration settings files to the 505XT
Designed for steam turbine control, the 505XT control  Upload configuration settings files from the 505XT to save
includes seven PID controllers (Speed, Ext/Adm, Cascade, on another device
Aux-1, Inlet, Exhaust, Acceleration) multiple start-up routines  Upload Alarm and Shutdown event log files
(manual, semi-auto, automatic, remote control), and multiple  Upload datalog trend information from the 505XT to view
protection functions (overspeed, critical speed range, max and save on another device
power, etc.) which can be configured by a user depending on  View real-time or saved trend files
the specific turbine application’s requirements. Users can
configure the 505XT’s different PID controllers, start routines, Communications between the 505XT and a plant DCS can
and protection levels themselves without the need for a also be performed through hard-wired connections.
special control engineer.

Figure 1. Example 505XT Screens

Cost‐Effective Design  Control 
The 505XT control is designed to function as the turbine
control, system sequencer, operator control panel, and first- The following PIDs are available to perform as process
out indicator. This encompassing design minimizes external controllers or limiters:
system devices as well as system installation, wiring, and  Speed/Load PID (with multiple dynamics & Adaptive PID)
troubleshooting.  Extraction/Admission Pressure PID
 Cascade PID (Header Pressure or Tie-Line Control)
This field-configurable controller allows major functional
 Auxiliary PID 1 (limiter or control)
changes to be made on-site, often by knowledgeable plant
 Inlet Header PID
personnel, and minor functional changes to be on-line as
process changes require. The 505XT control’s first-out-  Exhaust Header PID
indicator logic indicates internal as well as external system  Rotor Acceleration PID (on startup)
related alarm and shutdown conditions, greatly simplifying and
reducing system troubleshooting. System Protection 
Communications   Integral Overspeed Protection Logic & Test Capability
 First-out Indication (15 individual shutdown inputs)
The 505XT controls can communicate directly with plant  External Alarm Indication (15 individual alarm inputs)
Distributed Control Systems and/or CRT-based operator  Stuck in critical speed band logic
control panels, through four Ethernet ports using Modbus TCP  Bumpless transfer between control modes if a transducer
or OPC communication protocols, or via one serial Modbus failure is detected
port. The single serial port supports RS-232 or RS-485  Local/Remote control priority and selection
communications using ASCII or RTU Modbus protocols.  Internal CPU watchdog circuit in case of failure
 Password security for operation and configuration modes
 Woodward 03423a p.3

Control  Features 
Specifications   Critical Speed Avoidance (3 speed bands)
 Auto Start Sequence (hot & cold starts)
INPUTS  Multiple Ratio/Limiter Decoupling Modes
 Power: LV models = 18–32 Vdc  Manual Valve Control and Limiter(s)
HV models = 88–264 Vac & 90–150 Vdc  Security (program is password protected)
 Speed: 2 Passive MPUs or 2 Active Proximity  Adaptive Speed and Extraction PID Dynamics
probes  First-Out Indication (shutdowns)
(0.5—32 000 Hz)  Zero Speed Detection with proximity probe (< 0.5 Hz)
 Discrete Inputs: 20 Configurable Contact Inputs  Peak Speed Indication for overspeed trip
(optionally 16 additional inputs via LinkNet-HT modules)  Multi-lingual Display (English, Chinese, Portuguese,
 Analog Inputs: 8 Configurable 4–20 mA Inputs Japanese, and Spanish)
(optionally 16 additional inputs via LINKnet HT modules)  Remote analog setpoints for all PID controllers
(optionally 8 additional RTD inputs via LinkNet-HT  High Speed Digital Communications to Woodward
modules) actuators and power management products

OUTPUTS
 Valve/Actuator Drivers:
Control Accessories 
2 Actuator Outputs, 4–20 mA or 20–200 mA
 Discrete Outputs: RemoteView—Once installed on a computer or touch
8 configurable Relay Outputs (2 relays rated panel, the RemoteView software program can be used as
for 24 Vdc @ 5 A, 6 relays rated for 24 Vdc @ 2 an engineering workstation and/or remote operator control
A) panel. As an operator control panel, this software program
(optionally 16 additional outputs via LINKnet HT can be used to monitor all system parameters, start and
module) stop the turbine, and enable/disable all modes of operation.
 Analog Outputs: Control Assistant—The Control Assistant software
6 Programmable 4– 20 mA Current Outputs program functions as an engineering workstation and/or
(optionally 4 additional inputs via LINKnet) service tool that can be used with the 505 control to view
real-time trends, view saved trend files, or compare
COMMUNICATIONS
differences in configuration files. As an engineering
 Ethernet: 4 ports (Modbus TCP or OPC protocols)
workstation, this software program can be used to upload
 Serial: 1 Modbus port (ASCII or RTU) Comm Ports and download settings and log files to and from the 505
(RS-232 or RS-485 compatible) controller (details in product spec 03424).
 CAN: 4 ports (supports LinkNet-HT Nodes
VariStroke Actuators & General Power AppManager—Tool for setting the IP addresses of the
Management Devices) Ethernet ports, setting SNTP functionality, Program
upload/download capability, retrieving datalog files,
Functionality  Start/Stop the Display program (to change languages).

The 505XT’s control capabilities are:

Operating 
 Speed/Frequency Control Conditions 
 Extraction and/or Admission Header Pressure Control
 Turbine or Generator Load Control or Limiting
 –30 ° to +70 °C (with display)
 Turbine Inlet Header Pressure Control or Limiting
 Humidity: 5% to 95% non-condensing
 Turbine Exhaust Header Pressure Control or Limiting
Lloyd’s ENV2 test #1
 Plant Import/Export Power Control or Limiting
 Dry Heat: Lloyd’s ENV3
 Isochronous Load Sharing between units (with DSLC™-
 Shock: 10G, 3x axis per Woodward MS1 procedure
II control)
 Vibration: 8.2Grms, industrial skid mount per Woodward
 Control of any process directly related to unit load
RV1
Lloyd’s ENV2 test #1
Pollution Resistance
 Particulate Pollution Resistance: IEC 60664-1 Pollution
Degree 2 (normally only non-conductive pollution occurs)
 Gaseous Pollution Resistance: Module conformal
coating withstands NO2, CO2, SO2, and H2S gases
 Woodward 03423a p.4

Regulatory Compliance 
European Compliance for CE Marking
These listings are limited to only those units bearing the CE Marking.
 EMC Directive: 2014/30/EU COUNCIL DIRECTIVE
 LVD Directive: 2014/35/EU COUNCIL DIRECTIVE
 ATEX Directive: 2014/34/EU COUNCIL DIRECTIVE Zone 2, Category 3, Group IIG Ex ic nA IIC T4 X Gc IP20
Other International Compliance
 IECEx Ex ic nA IIC T4 Gc: Certificate No. IECEx CSA 15.0020X
 EAC CU-TR: Certified per Certificate No. RU C-US.МЮ62.В.04777 as 2Ex ic nA IIC T4 Gc X
North American Compliance
 CSA Listed for Ordinary Locations Certificate 70006135 (LR 79726)
 CSA Listed for Class I, Division 2, Groups A, B, C, and D, T4 at +70 °C: Certificate 70006135 (LR 79726)
Marine Compliance
 Lloyd’s Register (LR): Environmental Category ENV1, ENV2, ENV3, Lloyd’s Register Type Approval Test Specification
Number 1, 2013.
 DNV-GL: Temperature Class D, Humidity Class B, Vibration Class A, EMC Class A, Enclosure; Required protection according
to the Rules shall be provided upon installation on board, Standard for Certification No. 2.4, April 2006.

Figure 2. Basic Single Valve or Split Range Functional Control Diagram

 Woodward 03423a p.5

Figure 3. Basic Ext/Adm Functional Control Diagram

Figure 4. Optional/Configurable Isolated PID

 Woodward 03423a p.6

Figure 5. Typical 505XT Application

Figure 6. 505XT Dimensions

(Do not use for construction)
For more information contact:
PO Box 1519, Fort Collins CO 80522-1519, USA
1041 Woodward Way, Fort Collins CO 80524, USA
Phone +1 (970) 482-5811
Email and Website—www.woodward.com

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as authorized distributors and other authorized service and sales facilities
throughout the world. Complete address / phone / fax / email information for
all locations is available on our website.

This document is for informational purposes only. It is not to be construed as creating or

becoming part of any Woodward contractual or warranty obligation unless expressly
stated in a written sales contract.
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