9.1.2
Troubleshooting analogue-controlled governors (mA signal)
Problem The analogue-controlled governor does not respond when the controller tries to raise or lower the
frequency by changing the analogue output mA signal.
Solutions Ensure that the wiring from the controller to the governor is correct.
Ensure that the governor receives the analogue output mA signal.
Tools Screwdriver
Multimeter that can measure mA current
Insulated screw connector
Optional: Process meter
Method
1. Look in PICUS under Configure > Input/output > Analogue output > Function to check that the
Regulators > Governor > GOV output % function is assigned to the correct analogue output
terminals. Check the output type and characteristics under Configure > Input/output > Analogue
output > Output setup. If a Custom output curve is used, check the configuration of the curve.
2. Disconnect one of the analogue output connections.
3. Connect one of the multimeter leads to the available analogue output, and tighten to ensure that
there is a good connection between the output terminal and the measuring lead.
4. Set up the multimeter to read mA.
5. Use the screw connector to connect the other measuring lead from the multimeter to the
unconnected wire from the analogue output and tighten to ensure that there is a good connection.
6. Start the genset and let it run with the genset breaker open. Make sure that switchboard control is
deactivated.
7. Look at the reading on the multimeter.
• 0 mA:
◦ There is no current loop from the controller terminals to the governor. Check the wiring all the
way from the controller to the governor.
• Not 0 mA:
◦ There is a current loop from the controller terminals to the governor. Record the current
reading and the generator frequency, and continue troubleshooting.
8. Under Configure > Parameters > Generator > Nominal settings > Frequency, increase the
nominal frequency by 1 Hz. That is, if the nominal frequency is 50 Hz, increase the nominal
frequency parameter in the controller to 51 Hz, then record the current reading and generator
frequency.
• The current reading changes, but the frequency stays the same:
◦ The governor is not responding to the current signal. Check the governor, for example, by
connecting the process meter to the governor. Use a 0 to 24 mA signal to raise and lower the
genset frequency. If the process meter cannot raise or lower the genset frequency, then there
is a problem with either the governor or the wiring.
• The current reading changes a lot, but the frequency increases by less than 1 Hz:
◦ Adjust the governor control range on the governor.
9. Remember to return the nominal frequency to its normal value.
PPU 300 Commissioning guidelines 4189341106 UK
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