GFCI test successful with no hardware

[opb]

Hi James

I've flashed the pro mini and with no other hardware connected, just the mini connected via the serial-USB dongle, I get the following on the serial monitor:

Ground fault detection time: 19 ms
GFCI Test Successful
Starting in State A
FAULT: 5

I guess fault 5 is to be expected - no pilot voltage, but I wouldn't have expected it to pass the GFCI test. Would you expect it to do this if detached from the board?

Thanks

[fotherja]

Hi,
Interesting. Without the current transformer attached the GFCI test should not pass. I suspect a hardware problem. Can you use a multimeter to measure the voltage on A0 which is the processed GFCI signal. It should be 0v. Are you happy with the op-amps and their connections etc?

[fotherja]

Also, you shouldn't be getting a fault 5 code. I suspect you're getting this code because the pilot should be DC +12v but this isn't being produced accurately enough by the op-amps.

The op-amps can't necessarily swing their outputs to their supply rails. As such they need suppling with a slightly higher voltage than what you want them to produce. I think my power rails are +/- 13.5V. Use a multimeter to measure your +12V DC pilot signal and adjust your +ve power supply voltage until you get this. (I'd then set the -ve rail voltage to be equal in magnitude to the +ve rail)