Woodward 721 Use and care manual

Operation and Calibration Manual
___
WARNING
23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46
23 4 5 6 7 8 912 131
721 DIGITAL CONTROL
W
WOODWAR
OODWAR D
D
10 1411 15 16 17 18 19 20 21 22
W
WD D
OODW AR
OODW AR
AUXILIARY
COMMON
DISCRETE
COMMON
ABC E GHDF
DISCRETE INPUTS
APPLY +18 TO +40 VDC TO A CTIVATE
+-
+5 VDC
AUXILIARY
DEVICE
POWER
(50mA MAX)
REM
JPR
FOR
+
-5
VDC
SIGNAL
INPUT
#1
mA COM +
-mA COM
+
-mA COM
+
-mA COM
+
-
REM
JPR
FOR
+
-5
VDC
REM
JPR
FOR
+
-5
VDC
REM
JPR
FOR
+
-5
VDC
SIGNAL
INP UT
#2
SIGNAL
INPUT
#3
SIGNAL
INPUT
#4
18-40VDC
18W
SUPPLY
INPUT
+-CNO
RELAY
OUTPUT
#1
CNO
RELAY
OUTPUT
#1
CNO
RELAY
OUTPUT
#1
+-
ANALOG
OUTPUT
#1
+-
ANALOG
OUTPUT
#2
+-
ANALOG
OUTPUT
#3
+-
ACTUATOR
OUTPUT
+-
SPEED
SENSOR
INPUT#1
+-
SPEED
SENSOR
INPUT#2
+-
LOAD
SHARING
LINES
POWER
AND
CPU OK ALARM #1 ALARM #2
CONTACT POWER RATING
2.0 AMP RESISTIVE 28VDC
0.1 AMP RESISTIVE 115VAC
721 Digital Speed Control
For Marine PropulsionApplication
D/N 9907-717
WOODWARD GOVERNOR (JAPAN). LTD.,
251-1 Nakazawa, Tomisato-city
Chiba - ken, 286 - 0222, Japan
Phone: [phone] Fax: [phone]
Manual 26004

WARNING—DANGER OF DEATH OR PERSONAL INJURY
WARNING—FOLLOW INSTRUCTIONS
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.
WARNING—OUT-OF-DATE PUBLICATION
This publication may have been revised or updated since this copy was produced. To verify that
you have the latest revision, be sure to check the Woodward website:
www.woodward.com/pubs/current.pdf
The revision level is shown at the bottom of the front cover after the publication number. The
latest version of most publications is available at:
www.woodward.com/publications
If your publication is not there, please contact your customer service representative to get the
latest copy.
WARNING—OVERSPEED PROTECTION
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.
WARNING—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.
CAUTION—POSSIBLE DAMAGE TO EQUIPMENT OR PROPERTY
CAUTION—BATTERY CHARGING
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.
CAUTION—ELECTROSTATIC DISCHARGE
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.
IMPORTANT DEFINITIONS
• A WARNING indicates a potentially hazardous situationwhich, if not avoided, could result in death or
serious injury.
• A CAUTION indicates a potentially hazardous situation which, if not avoided, could result in damage
to equipment or property.
• A NOTE provides other helpful information that does not fall under the warning or caution
categories.
Revisions—Text changes are indicated by a black line alongside the text.
WoodwardGovernorCompanyreservestherighttoupdateanyportionofthispublicationatanytime.InformationprovidedbyWoodwardGovernorCompanyis
believedtobecorrectandreliable.However,noresponsibilityisassumedbyWoodwardGovernorCompanyunlessotherwiseexpresslyundertaken.
©1998byWoodwardGovernorCompany
AllRightsReserved

Manual 26004 721DSC for Marine PropulsionApplication
Woodward i
WARNING—THIS PUBLICATION MAY BE OUT OF DATE
The Japanese original of this publication may have been updated since
this translation was made. For the most current information, be sure to
check whether there is a Japanese version with a later revision.
CONTENTS
Page
Chapter1. General Information
Introduction ······································································································································································ 1
Application ······································································································································································· 1
721ControlAccessories ·············································································································································· 1
Chapter2. ElectrostaticDischargeAwareness
Summary ········································································································································································ 3
GeneralInformation ······················································································································································ 3
Chapter3. Installation
Scope ··············································································································································································· 5
Unpacking ······································································································································································· 5
Locationconsideration·················································································································································· 5
ElectricalConnection ···················································································································································· 6
PowerRequirement ····················································································································································· 6
Chapter4. Description ofOperation
General ············································································································································································ 9
ControlDynamics ·························································································································································· 9
SpeedReference ··························································································································································10
LoadTransfer ·································································································································································10
FuelLimit··········································································································································································11
MonitoringControl ·························································································································································11
Chapter 5. Entering ControlSet Points
Introduction ······································································································································································13
HandHeldProgrammerandMenus ·······················································································································13
ConfigureMenus ···························································································································································14
ServiceMenus ·······························································································································································15
AdjustingSetPoints ······················································································································································15
HandHeldProgrammerKeys ···································································································································16
SetPointsList ·································································································································································18

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Chapter6. Service andConfigure Menus
ConfigureMenus ·························································································································································· 21
ServiceMenus······························································································································································· 23
Display ······································································································································································ 23
Dynamics1 ······························································································································································ 23
Dynamics2 ······························································································································································ 25
SpeedSettings ························································································································································ 25
KWSettings ····························································································································································· 27
FuelLimit ·································································································································································· 27
Display2 ··································································································································································· 28
Alarms ······································································································································································· 29
Chapter7. MajorAlarmand MinorAlarm
MajorAlarm ···································································································································································· 35
MinorAlarm ···································································································································································· 35
721DSCSpecification ············································································ insideback cover
ILLUSTRATIONSAND TABLES
Fig1. HandHeldProgrammerFunctions ·························································································································· 16
Fig2. TypicalTransientResponseCurve ·························································································································· 31
Fig3. ControlGainasaFunctionofSpeedError ············································································································· 32
Fig4. ControlGainasaFunctionofControlOutput ········································································································ 32
Fig5. SpeedFilter ····································································································································································· 33
Fig6. TorqueFuelLimitCurve ·············································································································································· 33
Set Point Record Sheets ······························································································································· 37
Function Block Diagram ··············································································································AppendixP1
ControlWiringDiagram ···············································································································AppendixP4

Manual 26004 721DSC for Marine PropulsionApplication
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Chapter 1.
General Information
Introduction
This manual describes the Woodward 721 Digital Speed Control , 9907-717. For details on
721 control hardware , refer to Woodward manual 02770 (721 Digital Speed Control
Hardware manual).
Application
This 721 Digital Speed Control was designed as a marine propulsion engine control to use
with a changeable pitch propeller control. This control has two sets of control dynamics
which the operator can switch to get most suitable engine operation: either when only the
propeller shaft is driven, or when both the propeller shaft and the generator are driven.
Normally, generators are operated in isolation. However this control has a load transfer mode
to enable parallel operation in order to transfer the load to another generator.
721 Control Accessories
A hand-held programmer, part number 9907-205, is used to adjust and monitor the 721 DSC.
The programmer plugs into serial port J1 (9-pin D connector).

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Chapter 2
Electrostatic Discharge Awareness
Summary
All electronic equipment is static-sensitive, some components more than others. To protect
these components from static damage, you must take special precautions to minimize or
eliminate electrostatic discharges.
General Information
Follow these precautions when working with or near the control.
1. Before doing maintenance on the electronic control, discharge the static electricity on your
body to ground by touching and holding a grounded metal object (pipes, cabinets,
equipment, etc.).
2. 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.
3. Keep plastic, vinyl, and styrofoam materials (such as plastic or styrofoam cups, cup
holders, cigarette packages, cellophane wrappers, vinyl books or folders, plastic bottles,
and plastic ash trays) away from the control, the modules, and the work area as much as
possible.
4. 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.

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Chapter 3
Installation
Scope
This chapter contains general installation instructions for the 721 control. Power
requirements, environmental precautions, and location considerations are included to help
you determine the best location for the control. Additional information includes unpacking
instructions and electrical connections.
Unpacking
Before handling the control, read Chapter 2, Electrostatic Discharge Awareness. Be careful
when unpacking the electronic control. Check the control for signs of damage such as bent
panels, scratches, and loose or broken parts. If any damage is found, immediately notify the
shipper.
Location Considerations
Consider these requirements when selecting the mounting location:
•adequate ventilation for cooling
•space for servicing and repair
•protection from direct exposure to water or to a condensation-prone environment
•protection from high-voltage or high-current devices, or devices which produce
electromagnetic interference in excess of levels defined in EN50082-2
•avoidance of vibration
•selection of a location that will provide an operating temperature range of –40 to +70 °C (–
40 to +158 °F). A location providing an operating temperature range of 0 to +30 °C is
preferred.
CAUTION
The control must NOT be mounted on the prime mover.

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Electrical connections
Refer to the control wiring diagram in this manual for wiring details.
All shielded cable must be twisted conductor pairs. Do not attempt to tin the braided shield.
All analog signal lines should be shielded to prevent picking up stray signals from adjacent
equipment. Connect the shields to the point specified on the control wiring diagram. Wire
exposed beyond the shield should be as short as possible, not exceeding 50 mm (2 inches).
The other end of the shields MUST be left open and insulated from any other conductor. If
both ends of a shield are connected, the result may be worse than if the shield is not used.
DO NOT run shielded signal wires along with other wires carrying high voltage or high
current. See Woodward application note 50532,
Interference Control in Electronic
Governing Systems
, for more information.
Power Requirement
The 721 control requires the following power supply input voltages, with 18 watts as the
nominal power consumption at rated voltage:
•18-40 Vdc (24 Vdc or 32 Vdc nominal)
Discrete input voltages provide on/off command signals (like RUN/STOP or IDLE/START) to
the electronic control. Each discrete input requires 10 mA at its 24 Vdc nominal voltage
rating (for 24 volt switching logic).
CAUTION
To prevent damage to the control, do not power this control from any
sources with an output voltage exceeding 41 Vdc.
Run the power leads directly from the power source to the control.
DO NOT POWER OTHER DEVICES WITH LEADS COMMON TO THE CONTROL.
Do NOT turn off control power as part of a normal shutdown procedure. Leave the control
powered except for service of the system and extended periods of disuse. Use the “Close to
Run, Open to Shutdown” contact in the control wiring diagram to shut down the engine
normally.

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CAUTION
To prevent damage to the control, make sure that the alternator or other
battery-charging device is turned off or disconnected before
disconnecting the battery from the control.
CAUTION
To prevent damage to the engine, apply power to the 721 control at least
15 seconds prior to starting the engine. The control must have time to
complete its power up diagnostics and become operational. Do not start
the engine unless the green POWER AND CPU OK indicator on the 721
control cover comes on, because test failure turns off the output of the
control.

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Chapter 4
Description of Operation
General
This section provides an overview of the features and operation of the 721 Digital Speed
Control. In the last part of this manual, the control block diagram and the plant wiring
diagram are shown for reference in the following descriptions.
The 721 Digital Speed Control uses a 16-bit microprocessor for all control functions. All
control adjustments are made with a hand-held terminal/display (i.e. the hand-held
programmer) that communicates with the control via a serial port. The terminal/display is
disconnected from the control when not in service, to provide security against tampering.
The speed sensors contain a special tracking filter designed for reciprocating engines, which
minimizes the effects of flexible coupling torsionals. This provides exceptionally smooth
steady-state control and allows the control dynamics to be matched to the engine rather than
detuned to compensate for coupling torsionals. The speed signal itself is usually provided by
a magnetic pickup supplying from 1 to 30 Vrms to the control.
The control also provides 4 to 20 mA terminals for tachometer output, speed reference
output, and rack position output. Relay outputs provide a major alarm, a minor alarm, and
the load transferring indication.
Control Dynamics
The control algorithms used in the 721 control are designed specifically for reciprocating
engine applications.
To provide better transient performance, the control can be operated automatically with two
gain settings depending on engine speed error (speed error is the difference between the
speed setting and the actual engine speed). During steady-state operation with a constant
load, the control uses the base gain setting. The control automatically increases gain by an
adjustable ratio when a speed error exceeding an adjustable window occurs so that speed
error is minimized. Operation with base gain is restored once the control senses the return to
steady-state speed.
The control can also compensate for non-linear fuel systems and changes in engine dynamics
with load. The control dynamics are mapped as a function of actuator current (actuator
current is proportional to engine load). This provides optimal dynamics and smooth steady-
state operation for all conditions from no load to full engine load.
The control also provides two complete sets of dynamic adjustments which are selected
depending on the status of the Main Shaft Clutch On input. The two sets of dynamics are
provided for use where engine operating conditions change (e.g., when the engine drives both
the propeller shaft and the generator or when the engine drives only the generator).

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0
Speed Reference
The 721DSC provides local control of the speed reference with Raise Speed command (contact
input C), Lower Speed command (contact input D), Start Pos./Idle Speed selection (contact
input B), and Shaft Generator Operation command (contact input G). For remote speed
setting, the control provides a 4 to 20 mA Remote Speed Setting input. The Speed Reference
of 721DSC ramps to another set point with Raise/Lower rate when Raise/Lower Speed
command or Shaft Generator Operation command was input or Start Pos./Idle Speed
selection was changed. However, when the generator is synchronizing or when the load
transfer is being performed, the Load Transfer Rate is used to change the Speed Reference.
When the contact for Start Pos./Idle Speed selection input is opened, the Speed Reference is
fixed at Start Speed.
When the contact for Start Pos./Idle Speed selection input is closed, the Speed Reference
ramps to Idle Speed. When the Speed Reference reaches Idle Speed, it will be able to ramp to
another set point as directed by Raise/Lower Speed command or Shaft Generator Operation
command. The external Remote Speed Setting signal is enabled by closing both the Raise
Speed contact and the Lower Speed contact.
When the contact for Shaft Generator Operation is closed, the Speed Reference will ramp to
the speed specified with RATED SPEED set point and stay there. But the Raise Speed
contact and Lower Speed contact are enable while the engine is synchronizing for parallel
operation or performing Load Transfer. The Speed Reference returns to RATED SPEED
automatically after Load Transfer finished.
Load Transfer
This engine control system does not provide parallel operation in isochronousmode, but it can make two
engine-generator sets distribute the load which has been loaded by oneengine-generator set.
To transfer the generator load, the operator needs toopen the generator circuit breaker (GCBx) of the
engine generator set to which the load will be transferred. (that is, if the load will be transferred from the
starboard engine to the port engine in drawing 9951-626, GCB 2 must be opened, and vice versa.)
Connect the tie circuit breaker (TCB in drawing 9951-626). When one of the 721 controls detectsthat the
GCB xAUX contact (contact E) is open and the TCB contact (contact F) is closed, this control will switch
the operation mode from isochronous mode to KW droopmode to perform load transfer. The 721 control
whose GCB has been closed, will not switch operation mode , and continues to run in the isochronous
mode.
Synchronize both engines and close the GCB which was opened firstin this load transfer procedure.Next,
transfer the engine-generator load to another engine by raising the speed set pointof the 721 control
working in the load transfer mode..When the load levels of both engines are appropriate, open the TCB to
switch the engine operationmode to the isochronous mode.
Now, the load transfer has completed.

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Fuel Limit
The 721DSC has two fuel limits, Start Fuel Limit and Maximum Fuel Limits.
Start Fuel Limit (%) is the maximum percent actuator output during engine start-up. This
should be set to a value which gives optimum start characteristics, while minimizing smoke
emissions due to overfueling.
Maximum Fuel Limit (%) is the maximum percent actuator output during normal engine
operation. This limit should normally be set just above the output at full load.
Monitoring Control
721DSC’s analog input signals, analog output signals, and present discrete inputs status can
be monitored using the hand-held programmer.
Three 4-20mA outputs are provided for monitoring Engine rpm, Speed Reference, and Rack
Position (Actuator output), which are configurable at 4 mA and 20 mA.
Three relay outputs are provided for Major Alarm indication, Minor Alarm indication, and
Load Transferring indication.

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Chapter 5
Entering Control Set Points
Introduction
Because of the variety of installations, plus system and component tolerances, set points
input to two 721 controls could not be identical even if these 721 controls are installed in
same engine control systems. Therefore, the 721 control must be tuned to each system for
optimum performance.
This chapter contains information on how to enter control set points through the control's
menu system using the Hand Held Programmer. See the next chapter for prestart-up and
start-up settings and adjustments.
WARNING
An improperly calibrated control could cause an engine overspeed
or other damage to the engine. To prevent possible serious injury
from an overspeeding engine, read this entire procedure before
starting the engine.
Hand Held Programmer and Menus
The Hand Held Programmer is a hand-held computer terminal that gets its power from the
721 control. The terminal connects to the RS-422 communication serial port on the control
(terminal J1). To connect the terminal, slightly loosen the right-hand screw in the cover over
J1 and rotate the cover clockwise to expose the 9-pin connector. Then firmly seat the
connector on the terminal into J1.
The programmer does a power-up self-test whenever it is plugged into the control. When the
self-test is complete, the screen will display two lines of information. This is information
relating to the application. If it does not appear, press the ESC key. Pressing the 'ID' key will
change the display to show the software part number and the revision level of the control.
Please record this software part number and revision level because Woodward will need
these if you ever need factory service for any control problem.
The programmer screen is a four-line, backlighted LCD display. The display permits you to
look at two separate functions or menu items at the same time. Use the Ú“Up/Down Arrow”
key to toggle between the two displayed items. An “@” mark will be displayed at the left side
of the active line. The operator can change the set point only in the active line. The BKSP
and SPACE keys will scroll through the display to show the remainder of a prompt if it is
longer than the display screen's 18 characters.

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The 721 has two sets of menus; the Service menus and the Configure menus. The Service
menus allow easy access and tuning while the engine is running. The Configure menus may
only be entered if the I/O is shut down, and hence the engine stopped.
Configure Menus
To access the Configure menus, the engine must be shut down. Press the .key at the
control’s master screen.(“WOODWARD GOVERNOR, 721 DIGITAL CONTROL”) The display will
show “To Enable CONFIGURE, press *ENTER*”. Press the ENTER key and the display
will show, “To shutdown I/O, press *ENTER*”. Press the ENTER key and this will allow
you into the Configure menus.
NOTE
If the engine is running during this process, it will be shut down due to shutting
down the I/O of the control.
To move between the menus use the Wand Xkeys. To move through the set points within a
menu, use the Sand Tkeys. Once within a menu, to return to the menu header, press the
ESC key.
To exit the Configure menus press the ESC key. The set points will be automatically saved
when leaving Configure, and the control will automatically reboot itself.
CAUTION
Any values that are adjusted or tuned must be saved by pressing the ESC
key to reboot the control prior to removing power to the 721 control,
otherwise they will revert back to their original settings. Saving is done by
pressing the SAVE key on the hand held programmer.

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Service Menus
To access the Service menus, press the Tkey at the master screen (“WOODWARD GOVERNOR,
721 DIGITAL CONTROL”). To move between menus, and to move through set points within
menus, follow the instructions as for the Configure menus. Also to return to the menu
header, or to leave Service, follow the Configure instructions.
Adjusting Set Points
To adjust a set point, use the “Turtle Up” or the “Rabbit Up” keys to increase the value, and
the “Turtle Down” or “Rabbit Down” keys to decrease the value. The “Rabbit Up” and “Rabbit
Down” keys will make the rate of change faster than the “Turtle Up” and “Turtle Down”
keys. This is useful during initial set-up where a value may need to be changed significantly.
Where necessary, to select TRUE, use either the “Turtle Up” or the “Rabbit Up” keys, and to
select FALSE, use the “Turtle Down” or “Rabbit Down” keys.
To obtain an exact value, press the = key. Key in the required figure and press ENTER.
NOTE
This may be done only if the figure is within 10% of the existing value.
To save set points at any time, use the SAVE key. This will transfer all new set point values
into the EEPROM memory. The EEPROM retains all set points when power is removed from
the control.
CAUTION
To prevent possible damage to the engine resulting from improper control
settings, make sure you save the set points before removing power from
the control. Failure to save the set points before removing power from the
control causes them to revert to the previously saved settings.

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Hand Held Programmer Keys
The programmer keys do the following functions (see Figure 5-1):
(left arrow) Moves backward through Configure or Service, one menu at a time.
(right arrow) Advances through Configure or Service, one menu at a time.
(up/down arrow) Toggles between the two displayed items.
(up arrow) Moves backward through each menu, one step at a time.
(down arrow) Advances through each menu, one step at a time. Selects Service from
Master Screen.
(turtle up) Increases the displayed set point value slowly.
(turtle down) Decreases the displayed set point value slowly.
(rabbit up) Increases the displayed set point value quickly (about 10 times faster
than the turtle keys).
(rabbit down) Decreases the displayed set point value quickly (about 10 times faster
than the turtle keys).
– (minus) Increases set point values by one step at a time.
+ (plus) Decreases set point values by one step at a time.
(solid square) Not used.
ID Displays the 721 control part number and software revision level.
ESC To return to menu header or to main screen.
SAVE Saves entered values (set points).
BKSP Scrolls left through line of display.
SPACE Scrolls right through line of display.
ENTER Used when entering exact values and accessing Configure.
= (equals) For entering exact values (within 10%).
y(decimal) To select Configure.