EPM - RS485 fail

The export power manager needs rs485 communications to get data and control the inverters. Nothing will work if the rs485 communications is not working. An alarm code "RS485-all-fail" will appear if the EPM doesn't detect communications for one or more of the inverters.

You need to test the voltage between RS485A and RS485B to confirm it is working. This needs to be done at both points (device port and cable plug) on each device. For example if you have two inverters, you need to test four points (or photos).

If rs485 is working it should be around 0.5 – 5Vdc. When the communications is happening (from EPM) this can jump around abit, to stop this you can set “TRANSMIT” to ON on the EPM advanced settings (menu > advanced settings (0010) > TRANSMIT > ON > press ENT)

1. You need to confirm the EPM is pushing out RS485 communications by measuring the voltage between the two pins on the "COM-INV" port on the EPM. The example photo is shown below:

ac supply needs to be on, should see power LED and LCD information; need to be measuring dc voltage;

dc supply to inverters to be present so power led is on the inverters and LCD; need to be measuring dc voltage; needs to be removed from the EPM port so we only getting details from the inverter and the cable

Connect the cable back into the port so you can test the other side of the cable using that voltage output of the port on the EPM

1. Test points at the Inverter(s) (test one at a time)
   1. You need to confirm the Inverter is pushing out RS485 communications by measuring the voltage between the two pins on the "COMx" port (we have multiple ports which are all connected together, perform the test on the port you are using) on the inverter.

The example photo is shown below for the 2pin screw-in plug:

dc supply to inverters to be present so power led is on the inverters and LCD; need to be measuring dc voltage; make sure all other com ports are empty;

The example photo is shown below for the 2pin screw-in plug:

Ensure other end of cable is plugged into epm; need to be measuring dc voltage;

The example photo is shown below for the 4pinplug:

Ensure other end of cable is plugged into epm; need to be measuring dc voltage;