How do I fix an F51 External Fault code for a DG1 drive?

The external fault is something that is fed into a digital input. The first thing to do is go into programming and figure out what input is set for an external fault. There can be multiple external faults and there can also be normally open and normally closed external faults. To troubleshoot this fault. figure which input or inputs are programmed for external fault go into the monitor menu and see which input is causing the fault. The digital inputs can be seen in the monitor menu so as an example if DIN3 was programmed for external fault open, go to the monitor screen and look at DIN1-3 and see if 3 is on or off. For it to be faulted this should be off. The next step would be to check the voltage at this input to see if there is 24V there or not. If there isn’t troubleshoot the circuit that is supposed to supply this input. If there is 24V present it probably indicates there is a blown digital input and the option board will have to be replaced. Just to make sure this input is bad it would be advisable to jumper it straight to 24V and see if the input turns on. If it were for a fault on closed then it would work the opposite.