Woodward 723PLUS Technical Manual page 79

Manual 26482
Speed Sensor 2 (Speed Sensor Input #2)
Speed Sensor 2 is an optional input. Verify the MPU shield is tied only to the
723PLUS control ground and nowhere else in the system. If an MPU is used for
the speed sensor, measure the resistance across terminals 13 & 14. The
resistance depends on the MPU used, but should be less than 250 .
Disconnect the MPU connector at the MPU and the resistance value should be
greater than 250 . The typical input resistance for an MPU speed sensor is
250 ±50 . Check the resistance of the MPU and verify it is within the
manufacture's specifications. Reconnect the MPU connector.
A proximity probe cannot be tested using this manner. For a proximity probe,
verify the wiring to the proximity probe including the power supply wiring. The
MPU or proximity probe will be tested prior to running the engine.
Actuator Output (Analog Output #3)
Verify the actuator wiring from the 723PLUS control to the actuator. Verify proper
polarity as well as shield continuity. The shield should be connected only at the
723PLUS control and nowhere else in the system. Verify the actuator output
current (0–200 mA or 4–20 mA) matches the actuator input. Refer to the actuator
manual for proper wiring connections and signal input. The 723PLUS control,
actuator, and actuator wiring will be tested prior to starting the engine.
TORQUE INPUT (Analog Input #1)
The torque input signal comes from a torque transducer and strain gauges to
measure the engine shafts torque. The input signal must be direct acting
(increase torque to increase fuel and milliamps). To verify the torque input, view
the Torque input in Service mode, under header A**DISPLAY 1**, at prompt
TORQUE INPUT (1–5 Vdc).
Remote Speed Setting (Analog Input #2)
The remote speed input is intended to be used with only one speed setting
device, typically the bridge controller. However, in this applications the remote
speed setting comes from two or more speed devices. Ideally the multiple speed
setting devices need to be matched very closely. The calibration of the remote
speed setting input will be covered later. At this point, verify the wiring and any
relay logic that may be used to switch between multiple speed setting devices.
To verify the remote speed input, view the 02 SPEED REFERENCE (RPM), in
Service mode, under header A**DISPLAY 1**. Set the remote speed setting
device to its minimum speed position (1 Vdc). Verify the 02 SPEED
REFERENCE (RPM) prompt reads at or near the desired engine idle rpm. Move
the remote speed setting device to its maximum speed position (5 Vdc). Verify
the 02 SPEED REFERENCE (RPM) prompt reads at or near the desired engine
rated rpm. If multiple speed devices are used, repeat this process for all devices
to verify proper wiring. It may be useful to record the different signal input ranges
for all devices for the remote speed calibration. Verify the shield is connected
only to the 723PLUS control and nowhere else in the system.
Woodward
723PLUS Digital Marine Control
69