GEM Reading power on unused channels?

[zdenekjs]

I've got two GEMs in my system, and on one of them, I'm seeing non-zero power on a couple of unused channels. I haven't got the same channel hooked up on the second one yet to compare.

The GEM in question currently has Channels 1,3,5,7,8,9,11, and 17 hooked up.

The strange part is the power reading from Channel 3 also appears on Channels 2 and 30. The updates are in real time; when I change the current on Channel 3 it immediately shows up on channels 2 and 30.

We're not talking small numbers here, either. I'm reading 285 to 400W on these channels.

Is this normal? It looks like something is broke to me.

[ben]

I've got two GEMs in my system, and on one of them, I'm seeing non-zero power on a couple of unused channels. I haven't got the same channel hooked up on the second one yet to compare.

The GEM in question currently has Channels 1,3,5,7,8,9,11, and 17 hooked up.

The strange part is the power reading from Channel 3 also appears on Channels 2 and 30. The updates are in real time; when I change the current on Channel 3 it immediately shows up on channels 2 and 30.

We're not talking small numbers here, either. I'm reading 285 to 400W on these channels.

Is this normal? It looks like something is broke to me.

Make sure you don't have a Micro-CT hooked up like a Split-CT. Port combinations 1,2 and 3,4 are left unburdened as our Split-CTs have a built-in burden resistor. If you hook up an Micro-CT (which are unburdened) to either combination, it will cause bleed-over to other channels due to overloading the GEM.

Port combination 2,3 have a built-in burden resistor for Micro-CTs.

[zdenekjs]

All I've got on that unit are Micro-40s and Micro-50s. They're hooked up to pins 2&3 on each Channel.

I checked it three times; I've also attached photos so someone can tell me if I'm crazy or not.

IMG_2079.JPG (1.96 MiB) Viewed 6027 times

IMG_2080.JPG (2.13 MiB) Viewed 6027 times

[ben]

Looks good here.

If you move CH3 to CH4, does the issue disappear?

[zdenekjs]

It went away when I moved it to Channel 4...

[zdenekjs]

Whoops, spoke too soon. I now see the false currents on Channels 15 and 29. They just have labels so I didn't notice it at first.

[ben]

Whoops, spoke too soon. I now see the false currents on Channels 15 and 29. They just have labels so I didn't notice it at first.

Can you attach some screens from the GEM Setup Webpage Live Data screen?

EDIT: Feel free to email me directly too, might be a bit quicker. We can post the resolution here after.