Both the current active DTC and the previously cleared active DTC can be viewed through HMI or BESTCOMSPlus.
Alarm and protection functions
7.1 Alarm Grading
DGC-2020 distinguishes three alarm levels:
Pre Alarm: Indicates situations that require attention but are not yet urgent, flashing alarm LED, programmable output to horn
Alarm: Indicates a serious malfunction and immediately shuts down the machine
Status Only: Used for monitoring only, does not trigger alarms
7.2 Key Protection Parameters
Description of Protection Function Setting Range
Undervoltage (27) 70-576 Vac, two independent set values, supporting single/three-phase mode
Overvoltage (59) 70-576 Vac, two independent set values, supporting single/three-phase mode
Underfrequency (81U) 45-65 Hz with voltage suppression function
Overfrequency (81O) 45-65 Hz-
Reverse power (32) -50% to+5% set as a percentage of rated power
Demagnetization (40Q) -150% to 0% set according to the rated reactive power percentage
16 types of inverse time curves for overcurrent (51) optional components
7.3 Low Line Scale Factor
This is a feature of DGC-2020: when a contact input (programmed as Low Line Override) is detected to be closed, the protection setting value is automatically multiplied by a scaling factor. This function is applicable to reconfigurable generator sets that can operate at different voltage levels.
BEST logic+programmable logic
BEST logic+is the "electronic wiring" system of DGC-2020, which connects input, output, protection components, and logic gates through graphical drag and drop to achieve customized control strategies.
Programming constraints:
Each multi input entry requires a minimum of 2 inputs and a maximum of 4 inputs
Up to 5 levels of logical depth for any path
Up to 10 gates per level of logic
Up to 64 connection points for all paths
Common logical objects:
Input objects: physical inputs IN1-IN16, virtual inputs VIN1-VIN4
Output objects: physical outputs OUT1-OUTx, remote outputs OUT13-OUT36
Protective components: 27TRIP, 59TRIP, 51TRIP, 32TRIP, 40TRIP
Control components: AVR (voltage regulator), GOVERNOR (speed regulator) GENBRK/MAINSBRK
Logic gates: AND, OR, NAND, NOR, XOR, NOT
Typical applications:
Map ATS input to automatic generator start
Route the protection trip signal to the designated output contact
Implement timing control for delayed startup, cooling shutdown, etc
Troubleshooting Guide
9.1 The generator circuit breaker cannot close to the dead busbar
Confirm that the closing request has been initiated
Set DEAD BUS CL ENBL to ENABLE in BREAKER HARDWARE
Confirm that the generator status is stable (GEN STANLE indicator light is on)
Confirm that the bus status is DEAD (BUS DEAD indicator light is on)
Adjust the dead bus threshold and delay in BUS Deliberation Protection
9.2 The generator circuit breaker cannot be closed to the live busbar
Confirm that the synchronizer option exists
Confirm that both the generator and busbar are in a stable state
Check if the synchronizer is actively working (observe the speed regulator/AVR rise and fall pulses or simulate bias voltage changes)
Confirm that the Sync Fail activation delay is long enough
9.3 CANbus communication failure
Confirm that there is a 120 Ω terminal resistor at each end of the bus
Check that the CAN H and CAN L connections are not reversed
Confirm that the bus length is ≤ 40m and the branch line is ≤ 3m
Confirm that the ECU configuration settings match the actual ECU type (Volvo/MTU/standard J1939)
9.4 Abnormal sensor readings
Confirm that the sensor common terminal (terminal 11) is connected to the negative terminal of the battery and the sensor on the engine side
Measure with a multimeter that there is no voltage difference between terminal 2 (BATT -) and terminal 11
The sensor circuit should be routed separately from the AC power line and ignition line, using independent conduit
