Woodward 723PLUS User manual

Product Manual 02881
(Revision D, 7/2008)
Original Instructions
723PLUS Digital Marine Control
Two-engine Mechanical Load Sharing
8280-422, 8280-423
Installation and Operation Manual

General
Precautions
Read this entire manual and all other publications pertaining to the work to be
performed before installing, operating, or servicing this equipment.
Practice all plant and safety instructions and precautions.
Failure to follow instructions can cause personal injury and/or property damage.
Revisions
This publication may have been revised or updated since this copy was produced.
To verify that you have the latest revision, check manual 26311 , Revision Status &
Distribution Restrictions of Woodward Technical Publications, on the publications
page of the Woodward website:
www.woodward.com/publications
The latest version of most publications is available on the publications page. If
your publication is not there, please contact your customer service representative
to get the latest copy.
Proper Use
Any unauthorized modifications to or use of this equipment outside its specified
mechanical, electrical, or other operating limits may cause personal injury and/or
property damage, including damage to the equipment. Any such unauthorized
modifications: (i) constitute "misuse" and/or "negligence" within the meaning of
the product warranty thereby excluding warranty coverage for any resulting
damage, and (ii) invalidate product certifications or listings.
Translated
Publications
If the cover of this publication states "Translation of the Original Instructions"
please note:
The original source of this publication may have been updated since this
translation was made. Be sure to check manual 26311 , Revision Status &
Distribution Restrictions of Woodward Technical Publications, to verify whether
this translation is up to date. Out-of-date translations are marked with . Always
compare with the original for technical specifications and for proper and safe
installation and operation procedures.
Revisions—Changes in this publication since the last revision are indicated by a black line
alongside the text.
Woodward reserves the right to update any portion of this publication at any time. Information provided by Woodward is
believed to be correct and reliable. However, no responsibility is assumed by Woodward unless otherwise expressly
undertaken. Copyright © Woodward 1999–2008
All Rights Reserved

Manual 02881 723PLUS Digital Marine Control
Woodward i
Contents
WARNINGS AND NOTICES........................................................................... IV
ELECTROSTATIC DISCHARGE AWARENESS ..................................................V
CHAPTER 1. GENERAL INFORMATION...........................................................1
Introduction.............................................................................................................1
Application..............................................................................................................1
723PLUS Control Accessories...............................................................................2
CHAPTER 2. I/O OPERATION........................................................................9
Introduction.............................................................................................................9
Analog Output #1 (Terminal Block #15 and #16)...................................................9
Analog Output #2 (Terminal Block #17 and #18)...................................................9
Analog Output #3 (Terminal Block # 19 and #20)..................................................9
Analog Output #4 (Terminal Block # 21 and #22)..................................................9
Engine Speed Signal Input (Speed Sensor Input #1, #2—TB11, TB12, TB13,
TB14)....................................................................................................................10
Load Sharing Lines (TB9, TB10)..........................................................................10
Contact Inputs (Discrete Inputs A–H—TB29–TB36)............................................10
Fuel Rack Position Feedback (Analog Input #1—TB42–TB43)...........................12
Remote Speed Reference Input (Analog Input #2—TB45–TB46).......................12
Manifold Air or External Fuel Limit Input (Analog Input #3—TB48–TB49)...........13
±5 Volt Aux Input (Analog Input #4—TB51– TB52) .............................................13
Minor Alarm Contact Output (Relay Output #1—TB3, TB4) ................................13
Major Alarm Contact Output (Relay Output #2—TB5, TB6) ................................14
Clutch Permissive Contact Output (Relay Output #3—TB7, TB8).......................14
Power Supply Input (TB1, TB2)............................................................................15
+5 Vdc Auxiliary Device Power (TB38, TB40)......................................................15
J2 and J3..............................................................................................................15
POWER AND CPU OK LED.................................................................................15
FAILED SPD SENSOR #1 and #2 LEDs .............................................................16
ALARM #1 LED....................................................................................................16
ALARM #2 LED....................................................................................................16
CHAPTER 3. FUNCTION OPERATION...........................................................17
Introduction...........................................................................................................17
Speed Control.......................................................................................................17
Fuel Limiting .........................................................................................................26
Load Sharing........................................................................................................28
CHAPTER 4. SERVICE AND CONFIGURE MENUS..........................................30
Hand Held Programmer and Menus.....................................................................30
Configure Menus..................................................................................................35
Service Menus......................................................................................................42
Menu Default Values............................................................................................55
CHAPTER 5. INSTALLATION AND CALIBRATION...........................................61
Introduction...........................................................................................................61
Unpacking.............................................................................................................61
Power Requirements............................................................................................62
Location Considerations.......................................................................................62
Internal Jumpers...................................................................................................62
Electrical Connections..........................................................................................64
I/O Verification......................................................................................................65
I/O Calibration.......................................................................................................70
Engine Start-up.....................................................................................................78
Conclusion............................................................................................................82

723PLUS Digital Marine Control Manual 02881
ii Woodward
Contents
CHAPTER 6. TROUBLESHOOTING ...............................................................83
Introduction...........................................................................................................83
Major Alarm and Minor Alarm...............................................................................83
Both Speed Sensors Failed..................................................................................83
CPU Watchdog Fault............................................................................................83
POWER SUPPLY OK LED...................................................................................84
Alarm Delay Time.................................................................................................84
Alarm/Fault Resets...............................................................................................84
Speed Sensor 1 & 2 Fault ....................................................................................84
ALARM #1 LED ....................................................................................................84
ALARM #2 LED ....................................................................................................85
Overspeed Trip.....................................................................................................85
Remote Speed Input Fault....................................................................................85
Rack Position Input Fault......................................................................................85
Manifold Air Pressure Input Fault.........................................................................86
PID at Zero Fault ..................................................................................................86
Troubleshooting Procedure..................................................................................86
Table 6-1. Troubleshooting Procedure.................................................................87
CHAPTER 7. PRODUCT SUPPORT AND SERVICE OPTIONS ...........................94
Product Support Options......................................................................................94
Product Service Options.......................................................................................94
Returning Equipment for Repair...........................................................................95
Replacement Parts...............................................................................................95
Engineering Services............................................................................................96
Contacting Woodward’s Support Organization ....................................................96
Technical Assistance............................................................................................97
723PLUS CONTROL SPECIFICATIONS........................................................98
The following are trademarks of Woodward, Inc.:
DSLC
Woodward
The following are trademarks of their respective companies:
Modbus (Schneider Automation Inc.)

Manual 02881 723PLUS Digital Marine Control
Woodward iii
Illustrations and Tables
Figure 1-1. 723PLUS Marine Load Sharing System..............................................3
Figure 1-2a. Functional Block Diagram..................................................................4
Figure 1-2b. Functional Block Diagram..................................................................5
Figure 1-3a. Control Wiring Diagram......................................................................6
Figure 1-3b. Control Wiring Diagram......................................................................7
Figure 2-1. Communication Cable Wiring ............................................................16
Figure 3-1. Speed Sensor Roll-off Filter...............................................................18
Figure 3-2. Notch Filter.........................................................................................19
Figure 3-3. Speed Reference...............................................................................22
Figure 3-4. Gain Slope .........................................................................................24
Figure 3-5. Gain Window......................................................................................24
Figure 3-6. Typical Transient Response Curves..................................................25
Figure 4-1. Hand Held Programmer Functions ....................................................33
Figure 4-2. Service and Configure Headers.........................................................34
Figure 4-3. Watch Window PC Display................................................................35
Figure 4-4. Dynamics Maps..................................................................................37
Figure 5-1. 723PLUS Control Internal Jumpers...................................................63
Figure 5-2. Analog Output Calibration Example...................................................72
Figure 5-3. External Fuel Limit Calibration and Scaling.......................................76
Figure 5-4. Torque Fuel Limit Curve ....................................................................77
Figure 5-5. Start Fuel Limit...................................................................................77
Figure 5-6. Gain Slope .........................................................................................80

723PLUS Digital Marine Control Manual 02881
iv Woodward
Warnings and Notices
Important Definitions
This is the safety alert symbol. It is used to alert you to potential
personal injury hazards. Obey all safety messages that follow this
symbol to avoid possible injury or death.
DANGER—Indicates a hazardous situation which, if not avoided, will result
in death or serious injury.
WARNING—Indicates a hazardous situation which, if not avoided, could
result in death or serious injury.
CAUTION—Indicates a hazardous situation which, if not avoided, could
result in minor or moderate injury.
NOTICE—Indicates a hazard that could result in property damage only
(including damage to the control).
IMPORTANT—Designates an operating tip or maintenance suggestion.
Overspeed /
Overtemperature /
Overpressure
The engine, turbine, or other type of prime mover should be
equipped with an overspeed shutdown device to protect against
runaway or damage to the prime mover with possible personal injury,
loss of life, or property damage.
The overspeed shutdown device must be totally independent of the
prime mover control system. An overtemperature or overpressure
shutdown device may also be needed for safety, as appropriate.
Personal Protective
Equipment
The products described in this publication may present risks that
could lead to personal injury, loss of life, or property damage. Always
wear the appropriate personal protective equipment (PPE) for the job
at hand. Equipment that should be considered includes but is not
limited to:
Eye Protection
Hearing Protection
Hard Hat
Gloves
Safety Boots
Respirator
Always read the proper Material Safety Data Sheet (MSDS) for any
working fluid(s) and comply with recommended safety equipment.
Start-up
Be prepared to make an emergency shutdown when starting the
engine, turbine, or other type of prime mover, to protect against
runaway or overspeed with possible personal injury, loss of life, or
property damage.
Automotive
Applications
On- and off-highway Mobile Applications: Unless Woodward's control
functions as the supervisory control, customer should install a
system totally independent of the prime mover control system that
monitors for supervisory control of engine (and takes appropriate
action if supervisory control is lost) to protect against loss of engine
control with possible personal injury, loss of life, or property damage.

Manual 02881 723PLUS Digital Marine Control
Woodward v
Battery Charging
Device
To prevent damage to a control system that uses an alternator or
battery-charging device, make sure the charging device is turned off
before disconnecting the battery from the system.
Electrostatic Discharge Awareness
Electrostatic
Precautions
Electronic controls contain static-sensitive parts. Observe the
following precautions to prevent damage to these parts:
Discharge body static before handling the control (with power to
the control turned off, contact a grounded surface and maintain
contact while handling the control).
Avoid all plastic, vinyl, and Styrofoam (except antistatic versions)
around printed circuit boards.
Do not touch the components or conductors on a printed circuit
board with your hands or with conductive devices.
To prevent damage to electronic components caused by improper
handling, read and observe the precautions in Woodward manual
82715, Guide for Handling and Protection of Electronic Controls,
Printed Circuit Boards, and Modules.
Follow these precautions when working with or near the control.
1. Avoid the build-up of static electricity on your body by not wearing clothing
made of synthetic materials. Wear cotton or cotton-blend materials as much
as possible because these do not store static electric charges as much as
synthetics.
2. Do not remove the printed circuit board (PCB) from the control cabinet
unless absolutely necessary. If you must remove the PCB from the control
cabinet, follow these precautions:
Do not touch any part of the PCB except the edges.
Do not touch the electrical conductors, the connectors, or the
components with conductive devices or with your hands.
When replacing a PCB, keep the new PCB in the plastic antistatic
protective bag it comes in until you are ready to install it. Immediately
after removing the old PCB from the control cabinet, place it in the
antistatic protective bag.

723PLUS Digital Marine Control Manual 02881
vi Woodward

Manual 02881 723PLUS Digital Marine Control
Woodward 1
Chapter 1.
General Information
Introduction
This manual describes the Woodward 723PLUS Digital Marine Speed Controls,
8280-422 (low-speed engines, typically less than 100 rpm) and 8280-423
(medium-/high-speed engines, over 100 rpm). These controls are intended to be
used where mechanical load sharing and unit clutching is required.
Application
These controls are designed to regulate the speed and load of diesel engines in
dual-engine marine applications that require mechanical load sharing. The
applications include mechanically combined two-engine operation for main
propulsion and dredge operation, including those with flexible couplings (see
Figure 1-1).
Features include:
Clutch control and permissive logic
Soft loading and unloading
Mechanical load sharing by matching fuel rack positions
Advanced speed-sensing algorithms
Firing torsional filtering
Flexible coupling torsional filtering
Torque fuel limiting
Start fuel limiting
Manifold or external fuel limiting
Rack position sensor failure mode retains load sharing
Single-throttle operation for both engines during clutched operation
Inputs include:
Two magnetic pickups (MPUs) or proximity switches for sensing engine
speed, capable of filtering torsionals or providing redundant speed signals
4–20 mA remote speed-setting input
4–20 mA rack position feedback input
4–20 mA manifold or external fuel input
±5 Vdc auxiliary input
Eight discrete inputs (contact inputs) for: Run/Stop, Clutch Request, Clutch
Status, Idle/Rated, Raise Speed, Lower Speed, configurable contact for
either Overspeed Test or Emergency Declutch, and configurable contact for
either Alarm Reset or Dynamics 2.
Load sharing lines for the mechanical load sharing
Redundant communication ports J2 and J3 used for control status needed
between controls for proper clutching and loading.

723PLUS Digital Marine Control Manual 02881
2 Woodward
Outputs include:
Three 4–20 mA outputs which are configurable for: engine speed, engine
load, speed reference, actuator driver output, remote speed input, and PID
output
0–200 mA actuator output compatible with most Woodward actuators
One relay output for clutch permissive/close contact out
Two Alarm relay outputs: each is user-configurable for normally open/
closed contact output. There are 13 status choices to choose among for
these two alarms.
Serial port for a hand-held programmer to monitor and program the
723PLUS control
The 723PLUS control provides several functions including speed governing,
mechanical load sharing, clutching/declutching control logic including speed
matching during clutching, and soft engine loading/unloading. Each engine
requires a 723PLUS control along with the associated I/O connections,
transducers, and accessories (see Figure 1-4). The 723PLUS controls use a
master/slave relationship during clutching and load sharing operations. The
master unit is the first unit to close its clutch. The slave unit is the last unit to
close its clutch. The 723PLUS control’s primary job is speed control. When the
engines are clutched together, the 723PLUS control’s job also becomes one of a
load sharing control using the master’s speed reference. The engine clutching
process starts by matching (synchronizing) the engine speeds and then giving a
clutch permissive command. Once clutched, the engine is soft-loaded until the
loads are balanced mechanically (equal fuel-rack positions). The engines will
maintain equal loads (load sharing) during clutched operation. During a
declutching operation, the declutching engine is soft-unloaded and, when the unit
is at the unload trip level, a declutch command is given. This is a simplified
description, and several other items affect the 723PLUS control’s operation. See
Chapter 3, Function Operation, for more details.
The 723PLUS control consists of a single printed circuit board in a sheet metal
chassis. Connections are via three terminal strips and three 9-pin subminiature D
connectors. The 723PLUS control should be located in a protected location. See
Woodward manual 02877, 723PLUS Digital Control Hardware, for installation details.
This manual makes references to specific menu items or listings for
adjustments or monitoring. Generally, the menu listings will follow
the format of the mode you must be in first (Configure or Service),
second will be the name of the Header (in capital letters) while in that
mode, and finally the prompt (in capital letters) under that header.
For example, in Service mode, under header (*SPD CONTROL*), at
prompt ENGINE SPEED. All service headers are denoted by asterisks
(*) and all configure headers are denoted by the absence of the (*).
723PLUS Control Accessories
A hand-held programmer, part number 9907-205, is used to adjust and monitor
the 723PLUS control. The programmer plugs into the serial port J1 (9-pin D
connector).
Woodward has several LVDT signal conditioners that we can recommend for fuel
rack position transducer signal conditioning.
8272-824 (4–20 mA output, 24 Vdc input)
8272-834 (0–10 Vdc output, 24 Vdc input)

Manual 02881 723PLUS Digital Marine Control
Woodward 3
Figure 1-1. 723PLUS Marine Load Sharing System

723PLUS Digital Marine Control Manual 02881
4 Woodward
Figure 1-2a. Functional Block Diagram

Manual 02881 723PLUS Digital Marine Control
Woodward 5
Figure 1-2b. Functional Block Diagram

723PLUS Digital Marine Control Manual 02881
6 Woodward
Figure 1-3a. Control Wiring Diagram

Manual 02881 723PLUS Digital Marine Control
Woodward 7
Figure 1-3b. Control Wiring Diagram

723PLUS Digital Marine Control Manual 02881
8 Woodward
Figure 1-4. System Wiring Overview

Manual 02881 723PLUS Digital Marine Control
Woodward 9
Chapter 2.
I/O Operation
Introduction
Before handling the 723PLUS control, read Electrostatic Discharge
Awareness (page v).
This chapter contains the general input and output (I/O) description for the
723PLUS controls, 8280-422/-423.
The 723PLUS control hardware is intended to be a generic control platform
suitable for a wide range of applications. Each application is custom programmed
including the I/O function, range, and calibration. The I/O hardware is fixed, and
the wiring specifications for each 723PLUS control remain the same; however
the devices connected to I/O will vary.
Analog Output #1 (Terminal Block #15 and #16)
This analog output is a 4–20 mA signal. The signal can be changed to 0–1 mA
(see hardware manual). What this output displays is selected in Configure Menu.
The options are engine speed, engine load, speed reference, remote speed
setting, actuator output, and PID output.
Analog Output #2 (Terminal Block #17 and #18)
This analog output is a 4–20 mA signal. The signal can be changed to 0–1 mA
(see hardware manual). What this output displays is selected in Configure Menu.
The options are engine speed, engine load, speed reference, remote speed
setting, actuator output, and PID output.
Analog Output #3 (Terminal Block # 19 and #20)
This analog output is configured for the actuator output. It can be set for either
forward- or reverse-acting actuators in the Software Configure Menu. The
hardware configuration (jumper configuration) for the actuator output can either
be 0–200 mA (for 20–160 mA actuators) or 0–20 mA (for 4–20 mA actuators).
See the hardware manual (02877) for more details about the hardware jumpers.
The actuator terminal shaft position is proportional to the actuator output signal.
The actuator output is compatible with most Woodward actuators (hydraulic and
electric) that accept 20–160 mA or 4–20 mA. See Chapter 3, Function Operation,
for more information.
Analog Output #4 (Terminal Block # 21 and #22)
This analog output is a 4–20 mA signal and is used for display. What this output
displays is selected in Configure Menu. The options are engine speed, speed
reference, remote speed setting, actuator output, and PID output.

723PLUS Digital Marine Control Manual 02881
10 Woodward
Engine Speed Signal Input (Speed Sensor Input #1,
#2—TB11, TB12, TB13, TB14)
The two speed sensor inputs can be used with either a magnetic pickup (MPU)
for high-speed signals (400–10 000 Hz) or proximity switch for medium-speed
signals (7.5–1000 Hz). The inputs are determined by the hardware configuration
(jumper configuration). See the hardware manual (02877) for more information.
The maximum engine speed the 723PLUS control can control is 2200 rpm.
There are three different speed sensing modes: single input speed sensing,
redundant speed sensing, and torsional filtering of flexible couplings speed
sensing. There is an adjustable low-pass speed sensor filter, called SPEED
FILTER Hz, found in Service mode, under the header *DYNAMICS 1*, which is
used to filter out firing torsionals on both speed signal inputs regardless of the
speed sensing mode selected.
For single speed sensing, either input may be used. The unused speed signal
input will be failed when the engine is running.
If redundant speed sensing is desired, both speed sensing inputs are used. The
723PLUS will control using the signal that is the higher frequency.
If coupling torsional filtering is desired, both speed inputs are used. The coupling
torsional filtering is enabled in Configure mode, under the header CONFIG SPD
CONTROL, at the prompt called ENBLE TORSIONAL FLT. If ENBL TORSIONAL
FLT is “TRUE”, the torsional filtering is enabled and the redundant speed sensing
is the back up mode should one of the speed sensors fail. For torsional filtering,
SPEED SENSOR #1 MUST BE INSTALLED ON THE ENGINE SPEED-
SENSING GEAR and speed sensor #2 must be installed on the opposite side of
the flexible coupling. Both speed sensors must be installed on shafts rotating at
the same speed for either dual speed sensing mode.
Load Sharing Lines (TB9, TB10)
Because the load sharing line relay is contained in the control, no relay is
required between the control and the load sharing line bus. Use shielded cable
and connect the load sharing lines directly to terminals 9 (+) and 10 (–) of both
controls. When the clutch request contact (terminal #35) and the clutch engaged
contact (terminal #36) are high (+24 Vdc) and the LED above TB9 and TB10 is
illuminated, the control is in the isochronous load sharing mode. In this mode, the
internal load sharing line relay is energized and the load-matching circuit is
connected to the load sharing lines. The load sharing line voltage range is 0–3
Vdc which represents no-load to full-load rack position. When the companion
723PLUS control (slave) is clutching in, the companion senses the load sharing
line voltage and (once it is clutched in) increases its load until the load sharing
voltage is equal to the companion fuel rack position. Once the companion has
soft loaded (loads are matched), the 723PLUS control closes its internal load
sharing-relay, and the two engines are in isochronous load sharing.
Contact Inputs (Discrete Inputs A–H—TB29–TB36)
Discrete Input A—Run/Stop: Close this contact to activate the stop mode in the
723PLUS control. The 723PLUS control will command minimum fuel to the
engine.

Manual 02881 723PLUS Digital Marine Control
Woodward 11
Discrete Input B—Rated Speed: When 24 Vdc is applied to terminal 30, the
engine can be operated at a speed higher than idle. When +24 Vdc is removed
from terminal 30, the engines speed immediately begins to decelerate to idle at
the idle ramp time. The rated-to-idle ramp time is adjusted in Service mode,
under the header *SPEED REFERENCE*, at prompt DECEL RAMP (SEC).
Discrete Input C—Raise Speed: When 24 Vdc is applied to terminal 31, the
control raises speed at a rate determined by the raise speed rate. When 24 Vdc
is removed, speed remains at its current value. Actuating the Raise Speed
contact will cancel the ramps started by the Idle/Rated contact.
The raise speed rate ramp is adjusted in Service mode, under the header
*SPEED REFERENCE*, at prompt RAISE SPEED RATE.
The Raise Speed contact input is disabled when the Remote Speed Setting
mode is selected by closing both the Lower Speed and Raise Speed contacts.
Discrete Input D—Lower Speed: When 24 Vdc is applied to terminal 32, the
control lowers speed at a rate determined by the lower speed rate. When 24 Vdc
is removed, speed remains at its current value. Actuating the Lower Speed
contact will cancel the ramps started by the Idle/Rated contact.
The lower speed rate ramp is adjusted in Service mode, under the header
*SPEED REFERENCE*, at prompt LOWER SPEED RATE.
The Lower Speed contact input is disabled when the Remote Speed Setting
mode is selected by closing both the Lower Speed and Raise Speed contacts.
Discrete Input E—Configurable Contact: This contact can be configured for
one of two options: ALARM RESET or DYNAMICS 2. The selection is made in
Configure mode, under the header CONFIG OPTION at prompt USE CONT E
AS RESET. Default is DYNAMICS 2.
Discrete Input F—Configurable Contact: This contact can be configured for
one of two options: Overspeed Test or Emergency De-clutch. The selection is
made in Configure mode, under the header CONFIG SPD CONTROL, at prompt
CT F AS OVERSPD TEST. Default is Emergency De-clutch.
If at the prompt CT F AS OVERSPD value is “TRUE”, Discrete Input F is enabled
as an overspeed test contact and will have the following function. When 24 Vdc
is applied to terminal 34, the control speed reference can be raised with the
Raise Speed contact (terminal 31) to the HIGH SPEED SD point. Once 24 Vdc is
removed from terminal 34, the speed reference ramp is once again limited by the
Raise Speed Limit.
The adjustable high speed trip point value is found in Configure mode, under the
header ALARM/SD CONFIGURE, at prompt HIGH SPEED SD. The Raise Speed
Limit point is found in Service mode, prompt RAISE SPEED LIMIT, under the
header *SPEED REFERENCE*.
If at the prompt CT F AS OVERSPD value is “FALSE”, then Discrete Input F is
enabled as an Emergency Declutch contact and will have the following function.
When 24 Vdc is applied to terminal 34, the control will immediately issue a de-
clutch command and disable the unload ramp. The 24 Vdc must be removed
from terminal 34 before the control will try and clutch again.

723PLUS Digital Marine Control Manual 02881
12 Woodward
Discrete Input G—Clutch Request: When 24 Vdc is applied to terminal 35, the
clutching sequence begins. First the control looks to see if the other engine is
clutched in. If not, its speed ramps to idle and, after an adjustable dwell time at
idle, the clutch permissive contact out (terminals #7 and #8) will close. The clutch
permissive contact will open if the Clutch Engaged contact (Discrete Input H)
does not go high within the adjustable CLUTCH IN TIME. The 1 to 120 second
clutch-in time is set in Service mode, under the header *LOAD CONTROL*, at
prompt CLUTCH IN TIME. If the other engine is already clutched in, the control
will match (sync) its speed to the clutched-in unit and, after an adjustable dwell
time, issue the clutch permissive contact out (terminals #7 and #8 close). Once
the clutch has closed, the unit will soft load until loads are matched, and then it
will go into isochronous load sharing. The soft loading time is set in Service
mode, under the header *LOAD CONTROL*, at prompt LOAD RATE.
When 24 Vdc is removed from terminal 35, the de-clutching sequence begins.
First the control looks to see if it is the only unit clutched in. If it is the only unit
clutched in, it immediately opens the clutch permissive contacts (terminals #7
and #8). If both units are clutched in, the control asked to declutch will first soft
unload and, once unloaded, will open the clutch permissive contacts (terminals
#7 and #8). The soft unloading time is set in Service mode, under the header
*LOAD CONTROL*, at prompt UNLOAD RATE.
Discrete Input H—Clutch Engaged: This contact in is used to tell the control
the clutch status. When 24 Vdc is applied to terminal 36, the 723PLUS assumes
that its clutch is engaged (closed). If 24 Vdc is absent from terminal 36, the
723PLUS assumes that the clutch is disengaged (open). This signal must be
present for the unit to load share in either Manual mode or with a clutch request.
Fuel Rack Position Feedback (Analog Input #1—
TB42–TB43)
The Fuel Rack Position Feedback input is used by the 723PLUS for load sharing
and fuel rack indication. The 4–20 mA (or 1–5 Vdc) vs load scaling is adjusted in
Service. The fault levels for the input are hard-coded at 2 mA and 21 mA. If the
input signal is outside the limits, the 723PLUS control will default to using the
actuator output for load sharing and the rack position indication. When using a 4
to 20 mA transmitter, you must install a jumper between terminals 41 and 42 to
connect the internal 255 resistor in the loop. If any other analog input or output
is used in a common ground system, a current isolator must be installed.
Remote Speed Reference Input (Analog Input #2—
TB45–TB46)
The remote speed reference input is used to set the speed reference for the
723PLUS control during normal operation. The 4–20 mA vs rpm scaling is
adjusted in Service. The remote speed reference will be proportional to the
remote speed setting input as long as it is between 4 and 20 mA. The remote
reference is limited so it cannot go below the LOWER SPEED LIMIT or above
RAISE SPEED LIMIT. The fault levels for the input are hard-coded at 2 mA and
21 mA. If the input signal is outside the limits, the remote speed setting fault will
be latched. When using a 4 to 20 mA transmitter, you must install a jumper
between terminals 44 and 45 to connect the internal 255 resistor in the loop. If
any other analog input or output is used in a common ground system, an isolator
must be installed. See remote speed input calibration in Chapter 5, Installation
and Calibration, for more information.