'Electricity Meter Com Fail' followed by Frozen Inverter ('Waiting')

Setup: Twin AC3 inverters, each with an 8.2kW.h battery. Economy 7 tariff, so charging to XX% overnight and using/topping up on solar, during the day.

Yesterday, during the day, we got an 'Electricity Meter Com Fail' error on one inverter. This is not unusual for us, as we get this every few days, but it does not usually cause a problem. But on this occasion the inverter switched to a 'Waiting' status, after which it did not charge or discharge, for several hours - until I spotted this and restarted the inverter/Paused and Played. My questions are:

What exactly does 'Electricity Meter Com Fail' mean, in this context? Is this one of the inverters losing contact with one of the EM115 meters, or something else?

What exactly does an inverter status of 'Waiting' mean, in this context?

I keep meaning to check that our installer correctly used twisted pair cables for the EM115 meters, but it's not an easy job. Given the symptoms I have described, is there anything else I should be looking for? All other values appeared to be normal, at the time the error was thrown.

ToothyChris Are your AC3s connected as separate devices (each with it's own EM115s) or as a plant? From the KB:

2 - Status: The status of the inverter currently it can be either; normal, alert, waiting and lost.
2.1 - Normal: The inverter is running correctly and as planned.
2.2 - Waiting: The inverter is currently not charging or discharging.
2.3 - Warning/error: The system has a found a fault within the inverter.
2.4 - Lost: The inverter has lost its WiFi signal to upload the data packets.

I suspect the comm fail is that communications (over Modbus) have been lost. Poor connection? Check the plug with the Modbus from EM115 is securely pushed into the receptacle on the underside of the inverter?

Thanks Tim,

They are set up as a plant (Master/Slave), with one EM115 monitoring the incoming mains and the other monitoring the Solar generation.

As usual, the GE documentation is as useful as a chocolate teapot - but thanks for hunting it out! Normally I only see 'Waiting' when the battery is completely flat, with no solar to replenish it, but on this occasion it was showing a reported 61%.

Will try to get a good look at the EM115 wiring at some point soon.

Givenergy states that a SHIELDED twisted pair cable should be used. It does help if the cable drain wire is grounded at one point in the system - at the master.
A lot of installers just use cheap CAT5 cable - four twisted pairs with no shielding. The spare unused cables act like aerials - my system was picking up 60VAC with a house load of about 6kW. There may be comms errors - but the 'Meter comm fail' error normally means that the EM115/OM115 or GEM120CTM Modbus interface has gone fut..

Thanks "Slartibartfast"#p22381, I assume when you say the 'drain' you are referring to the shield? So a nice length of mic cable should be ideal.

The 'Drain' is a wire that runs through the cable - in contact with the shield. Each segment should have the drain wire connected to the next segment - twist together and solder - then cover with shrink wrap.

Slartibartfast Thanks for the education! I have seen some cables in the past, with that kind of uninsulated conductor, but I wasn't aware it was called a drain. Makes sense though.