Digital Voltage Regulator Caterpillar

Fault Handling

Usage:

SR4B 1BN

Note: For earlier digital voltage regulators go to Testing And Adjusting, "Fault Handling For Earlier Digital Voltage Regulators".

Fault Identification

Check the excitation.
1. Use a multimeter across the exciter field outputs F1 and F2. A multimeter should be set for VDC. Another way to verify that the regulator is providing excitation is by looking at parameter :55. Parameter :55 describes excitation current.
  Expected Result: The regulator is providing excitation to the generator.
  Results:
  - OK: Go to Step 2.
  - NOT OK: Go to Step 4.
Check the status of the alarm.
1. Check the display on the digital voltage regulator.
2. Check the status of the alarm output.
  Expected Result: The display on the digital voltage regulator is flashing or the alarm output is off. When alarm output is off, an alarm is active.
  Results:
  - OK: An alarm has occurred. The alarm is active. No new alarms will be detected until the fault has been reset. However, fault detection is still enabled. Go to Step 5.
  - NOT OK: Go to Step 3.
Check the status of the latest fault.
1. Check if a new alarm has been logged in parameter :92. Parameter :92 describes the latest fault.
  Expected Result: A new alarm has been logged in parameter :92.
  Results:
  - OK: A fault or alarm has occurred and has been reset. Troubleshoot the problem using the code in parameter :92 and the service manual (or clear the alarm). Go to Testing And Adjusting, "Fault Handling", section Fault Clearing.
  - NOT OK: No new alarm has occurred. STOP.
Check the status of the fault.
1. Check the display on the digital voltage regulator.
2. Check the status of the fault output.
  Expected Result: The display on the regulator is flashing or the fault output is off. When fault output is off, a fault is active.
  Results:
  - OK: A shutdown fault has occurred and is active. No new alarms/faults will be detected until this fault is reset. Go to Step 5.
  - NOT OK: Refer to Testing And Adjusting, "Troubleshooting". STOP.
Check the shutdown fault log.
1. Check the number logged in the shutdown fault log. The shutdown fault log is described by parameter :92. Check the flashing number on the display.
  Expected Result: The number starts with a 6 (6xx).
  Results:
  - OK: The number starts with a 6 (6xx). An alarm has occurred. This will not shut down the digital voltage regulator. The alarm is resettable without removing power by activating either parameter :96, the external fault reset switch contact, or by cycling the 24 VDC. Follow the troubleshooting procedures in the service manual for the alarm code shown in parameter :92. Continue the procedures until the alarm has been reset.
  - NOT OK: The number does not start with a 6 (6xx). Go to Step 6.
Check the shutdown fault log (continued).
1. Check the number logged in the shutdown fault log. The shutdown fault log is described by parameter :92. Check the flashing number on the display.
  Expected Result: The number starts with a 7 (7xx).
  Results:
  - OK: The number starts with a 7 (7xx). A resettable fault has occurred. This fault is resettable without removing power by activating either the shutdown fault reset parameter :96, the external fault reset switch, or by cycling the 24 VDC. Follow the troubleshooting procedures in the service manual for the fault code shown in parameter :92 and any possible active alarm shown in parameter :93. Note, that if the engine is running when the fault is reset, the digital voltage regulator will provide excitation to the generator. Continue the procedures until the fault has been reset.
  - NOT OK: The number does not start with a 7 (7xx). Go to Step 7.
Check the shutdown fault log (continued).
1. Check the number logged in the shutdown fault log. The shutdown fault log is described by parameter :92. Check the flashing number on the display.
  Expected Result: The number starts with an 8 (8xx).
  Results:
  - OK: The number starts with a 8 (8xx). A non-resettable fault has occurred which is resettable only after removing all power to the digital voltage regulator, troubleshooting and correcting the problem, and reapplying the power. Follow troubleshooting procedures in the service manual for the fault code shown in parameter :92 and any active alarm code in parameter :93. Hardware output driver(s) is/are reset, unit is operational, display returns to :01, and the fault is still logged in the latest fault log, parameter :92. If an active alarm was present when the fault was received, then it will be found in the previous fault log, parameter :93. The display stops flashing to indicate all alarms and faults are reset. New alarms/faults may be detected again. Go to Testing And Adjusting, "Fault Handling", section Fault Clearing.
  - NOT OK: A number is logged in shutdown fault log, parameter code :92 or is flashing in the display starting with a 9 (9xx). This indicates a severe fault has occurred and the unit must be replaced. STOP.

An alarm/fault has occurred and has been reset. The digital voltage regulator is fully operational, the alarm/fault is reset but not cleared. A 6xx, 7xx, or 8xx is logged in the fault log, parameter :92. If another alarm/fault is received, it will be logged in parameter :92 and the original contents of parameter :92 will be shifted to parameter :93.

In order to clear the alarm/faults, select parameter :94 on the display and press the function key. The regulator screen blanks briefly and returns to ":01". Fault value in parameter :92 is moved to parameter :93 and parameter :92 is cleared to "0000".

Note: If another alarm/fault has occurred, the new number will be logged in parameter :92. No change will occur to parameter :93. Return to Testing And Adjusting, "Fault Handling", section Fault Identification, Step 1.

Note: In order to clear the previous fault (parameter :93), select parameter :94 on the display and pressing the function key. Parameter :93 is cleared to "0000". Parameter :92 remains at 0000 and the display returns to ":01". STOP.