GEM PT setting?

[jloram]

My GEM went berzurk today. All the power values jumped to wildly high values. I logged into the the GEM's settings panel and discovered that the measured line voltage was reading in the mid-900 volts!, the PT values were something like 250/5 (from memory)... Since default values are not listed in the documentation, I tinkered for a while and finally came here to the forum to search though messages until I discovered a message suggesting PT values of 187/3. I tried those values and the measured line voltage came down to the high 80 VAC... I measure the open circuit voltage of the PT xformer with a high quality RMS volt meter at 14.4 - 14.5 volts AC-RMS when the actual line voltage measure 121.3 VAC-RMS. After tinkering with the "PT Type" I found I had to set it to 239 (Range =3) in order to have the GEM report the same voltage as the volt meter. Does the above suggest any problems with the GEM or the xformer?

Would someone provide significantly more info on "PT Range" and "PT Type" values, please?

-john-

[jloram]

I had to change my PT valve from 187 to 190 to get accurate watt readings.

I would say 239 is a big change. I would just monitor for a while, it should not change.

Took a look at it about 5 hours later and the GEM was showing a voltage of about 129 VAC. Had to lower the PT value to 225 to get the GEM down to what the volt meter was showing (121.5 VAC-RMS)....

[Teken]

For reference my GEM has always been set to 187 / 3 and the line voltage was dead on. Some where in the latest 2.XX firmware / ENG 1.XX updates something has changed.

I have advised Brultech to look into this more as this is not a line issue on my side.

Teken . . .

[ben]

For reference my GEM has always been set to 187 / 3 and the line voltage was dead on. Some where in the latest 2.XX firmware / ENG 1.XX updates something has changed.

I have advised Brultech to look into this more as this is not a line issue on my side.

Teken . . .

The earlier PTs had a higher output, so the PT Type would be a bit lower. The earlier one will have "CUI Stack" as the name, the newer ones will say "BrulTech".

Depends on whether or not you have a jumper installed on the GEM, the jumper is right beside where the wall transformers plug in.

Right now, if you have a jumper:

BrulTech PT Type: 194 Range: 3
And likely: CUI Stack PT Type: 187 Range: 3

If not:

BrulTech PT Type: 194 Range: 4
CUI Stack PT Type: 187 Range: 4

Ben

[Teken]

For reference my GEM has always been set to 187 / 3 and the line voltage was dead on. Some where in the latest 2.XX firmware / ENG 1.XX updates something has changed.

I have advised Brultech to look into this more as this is not a line issue on my side.

Teken . . .

The earlier PTs had a higher output, so the PT Type would be a bit lower. The earlier one will have "CUI Stack" as the name, the newer ones will say "BrulTech".

Depends on whether or not you have a jumper installed on the GEM, the jumper is right beside where the wall transformers plug in.

Right now, if you have a jumper:

BrulTech PT Type: 194 Range: 3
And likely: CUI Stack PT Type: 187 Range: 3

If not:

BrulTech PT Type: 194 Range: 4
CUI Stack PT Type: 187 Range: 4

Ben

Ben,

Great reference information for those to follow. But, the problem I see is that something has changed via programming from previous GEM firmware updates. I have never had to modify the PT values before and the line voltage has been spot on when comparing it to the Fluke measurements at the panel.

Since the various COM 2.XX / ENG 1.XX firmware release these high / low voltage readings have appeared out of no where. I just wanted to clarify that this problem is present now and should be reviewed moving forward.

Teken . . .

[ben]

Ben,

Great reference information for those to follow. But, the problem I see is that something has changed via programming from previous GEM firmware updates. I have never had to modify the PT values before and the line voltage has been spot on when comparing it to the Fluke measurements at the panel.

Since the various COM 2.XX / ENG 1.XX firmware release these high / low voltage readings have appeared out of no where. I just wanted to clarify that this problem is present now and should be reviewed moving forward.

Teken . . .

Gotcha. I'll let Paul know.

What wall transformer do you have?

Ben

[Teken]

Ben,

Great reference information for those to follow. But, the problem I see is that something has changed via programming from previous GEM firmware updates. I have never had to modify the PT values before and the line voltage has been spot on when comparing it to the Fluke measurements at the panel.

Since the various COM 2.XX / ENG 1.XX firmware release these high / low voltage readings have appeared out of no where. I just wanted to clarify that this problem is present now and should be reviewed moving forward.

Teken . . .

Gotcha. I'll let Paul know.

What wall transformer do you have?

Ben

I have a CUI Stack transformer in place. What is strange is that sometimes like the other member the GEM will *Settle Down* and the displayed voltage will be lower than when initially monitored.

I am not talking about 1 volt swing up or down. We are talking about 3-5 volts in VAC swing and this is not present when measuring the line voltage at the panel or any other outlet.

This is important to me as I have safety systems that reference this line voltage. If the system *believes* its too high / low then devices will be disconnected or turned on.

I rather not have false readings and having the safety systems kick in when not required.

Teken . . .

[jloram]

Uploaded verion 2.38 of COM Firmware and the 'high' voltage reading dissapeared. The voltage readings returned to normal... That is to say, I had to reset the value of PT Type to 193, inorder to get a correct reading....

-john-

[Teken]

Ben / Paul,

Can you guys please review the latest COM / Engine firmware and see if there is something amiss with the voltage detection?

The GEM is indicating 2-6 volt lower readings then the actual line voltage. For what ever reason this problem seems to go away and settle down. Is it possible that this is the cause of the random spike events I am seeing on various channels?

Teken . . .

[ben]

Ben / Paul,

Can you guys please review the latest COM / Engine firmware and see if there is something amiss with the voltage detection?

The GEM is indicating 2-6 volt lower readings then the actual line voltage. For what ever reason this problem seems to go away and settle down. Is it possible that this is the cause of the random spike events I am seeing on various channels?

Teken . . .

Lower voltage would mean a lower reading, so that wouldn't cause a spike. Does the spike happen on the DashBox?

Can you check to see if your PT Type has changed at all compared to the defaults indicated in this thread?

Ben