Pid At Low Level Fault; Troubleshooting Procedure - Woodward 723PLUS Technical Manual

723PLUS Digital Marine Control
Another method of switching to the backup actuator fuel demand load sharing is
by exceeding the torque deviation. The torque signals from both engines are
measured in both 723PLUS controls. If the torque signals are different by a
certain percentage and for a certain period of time, both units will switch to using
the back up Actuator Fuel Demand load sharing. An alarm reset will switch back
to using the Torque Signals for load sharing.
The speed control PID at Low Level fault is latched when the speed control PID
output has integrated to the minimum fuel level. The PID at Low Level fault is an
indication that the engine is being motored by the other unit. The fault has its own
fault delay time. The delay time is set at the prompt 06 PID @ ZERO TIME. The
minimum fuel level is also adjustable. The 05 PID @ ZERO LEVEL is the
actuator command percentage used to determine where "minimum" fuel is. 06
PID @ ZERO TIME and 05 PID @ ZERO LEVEL are found in E**ALARM/SD
CONFIGURE**. Depending on the linkage arrangement, the PID @ ZERO
LEVEL should be set near minimum fuel and lower than the lowest actuator
command for normal operation. The status of the fault is found at prompt 11 or
12 PID @ LOW LEVEL in either the C**MAJOR ALARMS** or D**MINOR
ALARMS** headers, if the PID at Low Level fault has been selected as one of
these alarms. If the PID at Low Level is used, we recommend that the PID at Low
Level fault be configured to activate one of the alarms.

Troubleshooting Procedure

Table 6-1 is a general guideline for isolating system problems. The service
personnel should be thoroughly familiar with the contents of this manual as well
as governor theory involving precise control of engine speed. This guide
assumes the system wiring, soldering connections, switch and relay contacts,
and input and output connections are correct and in good working order. Make
the checks in the order indicated. Various system checks assume that the prior
check have been properly done.
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.
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PID at Low Level Fault

Manual 26482
Woodward