Suddenly inconsistent voltage on GEMS

[gtallan]

Hi, I haven't really posted here before but have had a GEM monitoring energy usage for perhaps 6 years, with the addition of a dashbox 1-2 years ago...

I just noticed that my measurements recently are all over the map, and the voltage detected is varying wildly between 0-300V - which clearly can't be correct!

If I measure the voltage out of the PT with a dvm, it shows around 14.5V AC, which is a bit higher than the 12V printed on the transformer but might yet be "normal". I doesn't appear to be varying wildly (within the slow sample time of the dvm anyway). I picked up another inexpensive 12V AC adapter from amazon which measured 14.8V AC, so somewhat consistent there.

Is there any kind of internal damage to the GEM which might cause this wildly inconsistent reading? I have not tried cleaning the PT connector yet as suggested in some similar posts, but this seems like too extreme a swing in readings to be caused by that (yes, I should still try it!).

The GEM itself is at ENG firmware ver: 129.177 and COM firmware ver: 5.13 (the latter as of yesterday, before that it was at the longstanding 4.xx release - perhaps 4.33?)

Thanks for any suggestions.

[ben]

Hi, I haven't really posted here before but have had a GEM monitoring energy usage for perhaps 6 years, with the addition of a dashbox 1-2 years ago...

I just noticed that my measurements recently are all over the map, and the voltage detected is varying wildly between 0-300V - which clearly can't be correct!

If I measure the voltage out of the PT with a dvm, it shows around 14.5V AC, which is a bit higher than the 12V printed on the transformer but might yet be "normal". I doesn't appear to be varying wildly (within the slow sample time of the dvm anyway). I picked up another inexpensive 12V AC adapter from amazon which measured 14.8V AC, so somewhat consistent there.

Is there any kind of internal damage to the GEM which might cause this wildly inconsistent reading? I have not tried cleaning the PT connector yet as suggested in some similar posts, but this seems like too extreme a swing in readings to be caused by that (yes, I should still try it!).

The GEM itself is at ENG firmware ver: 129.177 and COM firmware ver: 5.13 (the latter as of yesterday, before that it was at the longstanding 4.xx release - perhaps 4.33?)

Thanks for any suggestions.

Can you check the power supplies versus the notice at https://www.brultech.com/contact?

If it's that type, check the PT settings to make sure they've haven't become corrupted (feel free to email me or dump your settings here and I can look them all over).

[gtallan]

Can you check the power supplies versus the notice at https://www.brultech.com/contact?

If it's that type, check the PT settings to make sure they've haven't become corrupted (feel free to email me or dump your settings here and I can look them all over).

Thanks Ben, I had never noticed that about the power supplies. Sure enough, the GEM has the older PSU type while the dashbox has the newer one. So this *could* be related.

What I did on Friday evening was a complete power cycle of the GEM, and that did appear to improve things - the voltage varied for a short time, and then settled down, since when it's mostly working normally, but there is still an occasional glitch in the voltage measurement, as seen in this screen grab (having a bit of trouble understanding how to embed images in the forum - I don't really think these spikes up to ~180V are likely to be real:



It's been a long time since I did the initial setup, but the PT settings are "PT Type" 238, "PT Range" 4