Conclusion; Quick Calibration Check - Woodward 723PLUS Technical Manual

723PLUS Digital Marine Control
Figure 5-4 illustrates how the Torque Load Sharing scheme works. The primary
control loop for the engines is speed. It will always try to maintain the speed
control loop first. The torque sensors from both engines are sent to each
723PLUS. When both clutches are closed, the speed references are biased up or
down, which in turn increases or decreases the fuel a small amount until the
torques signals are balanced. The Load Sharing scheme is the secondary control
loop and only has about a 10% change over the Speed Control Loop. The normal
running condition is when speed is in control and the Speed Bias coming from
the Load Sharing is biased to zero. Also illustrated in this figure is the back-up
Actuator Fuel Demand load sharing. If the Torque Signals fail or if the deviation
between the two torque signals is too large, both units will switch to the back-up
load sharing using Actuator Fuel Demand. This is why it is imperative that the
calibration of the these two signals is done with care.
The 723PLUS control is now calibrated and adjusted for normal operation. If any
problems are experienced during the calibration or adjustments, see Chapter 6
for troubleshooting. We recommend you check the system operation under all
conditions to verify proper setup and calibration of the 723PLUS controls. If any
accessories, including transducers, are replaced, the respective input needs to
be calibrated again for the new accessory.

Quick Calibration Check

Listed below is a quick guide for the calibration:
1. Assure that each engine is stable throughout its load range, both by itself
and clutched together. If for some reason the engine is unstable or the
actuator is oscillating, this can be fixed by adjusting one of the gain
variables in the dynamics menus. Knowing which gain variable to tune can
be a little tricky, as the gains are variable with speed, and they switch when
both engines are clutched. Assure that you know which Gain term to tune
before making an adjustment.
2. Analog Output #2—Engine Speed / Tachometer Output. This 4–20 mA
output is used by the TANO System to read engine speed and the local
engine speed tachometer by the engines. The adjustments for this output
are located in the Service Menu: M**ANALOG IN/OUT CALIB**, under the
02 TACH OUT MIN and 03 TACH OUT MAX. These are listed in rpm, and
the default is 0–1225 rpm.
3. Analog Output #4—Rack Position Output. This 4–20 mA output is used by
the TANO System to read the fuel rack position on the engine. There is a
Heinzmann rotary converter that converts Rack Position to a 1–5 Vdc signal.
This signal is sent to the 723PLUS, but is basically passed through to the
TANO System. To calibrate this output, manually pull the governor fuel rack
to minimum fuel and make sure the output in Service Menu: M**ANALOG
IN/OUT CALIB**, under the 08 RACK OUT (4–20 mA) reads 4.0 mA. Pull
the governor fuel rack to maximum fuel and make sure the output in Service
Menu: M** ANALOG IN/OUT CALIB**, under the 08 RACK OUT (4–20 mA)
reads 20.0 mA. Adjust 06 RACK OUT AT MIN and 07 RACK OUT AT MAX
if these values are not within specifications. There are other adjustments on
the Heinzmann converter box located directly beneath the 723PLUS. These
adjustments are usually what is adjusted to provide a 4-20 mA signal to the
723PLUS, out of the 723PLUS and to the TANO system.
80

Conclusion

Manual 26482
Woodward