2 questions - 1 wire and PT Values

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brassfly
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Joined: Sun Mar 12, 2017 7:45 pm

2 questions - 1 wire and PT Values

Post by brassfly » Mon Mar 20, 2017 8:04 pm

Hello! I'm working on getting my GEM back up and running after a while of it being neglected. I've got it running and sending values, but I don't think my values are correct. The closest I could get my voltage to show was 123.9v, whereas its actually 124.1 which is pretty close, but I wanted to mention it. I had to play with the PT settings and used PT Type 135/Range 4. It was the only way i could get it close to the correct voltage. I tried 194/4 and I got 350volts. Could anyone tell me the correct way to get that set? I did look in forums, but I couldn't find the details on where to set it.

Also, my 1 wire setup, I currently have it wired, Ground (GEM side) to VDD and Ground on the sensor, and 1-wire (GEM side) to DQ on the sensor. I can read the serial number off of it and put it in the Temp Degree page, but on the Live Data, it reads nc F. Anyone have any pointers?
Teken
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Re: 2 questions - 1 wire and PT Values

Post by Teken » Mon Mar 20, 2017 10:31 pm

Hello,

The base PT values are listed here for the various iterations of the GEM board releases. If a jumper is installed on the header labeled HD7 behind the power input on the GEM:

Older revision GEM's (black board) are:

Type: 187
Range: 3

If no jumper:

Type: 194
Range: 4

New revision GEMs (blue board) are:

Type: 238
Range: 4

There have been a few instances were the barrel connectors and the plug jack (PJ) were dirty. So please ensure you remove both the power supply and PT radio jack and clean both gently with a Q-Tip with cleaning agent. Once both PSU and PT are clean insert both of them firmly into the barrel connector gently and ensure a good connection.

If your *True RMS* DMM indicates PT *Type* needs to be adjusted to match the line voltage do so appropriately. Sorry I don't follow what your asking regarding the 1 wire sensor?
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ben
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Re: 2 questions - 1 wire and PT Values

Post by ben » Tue Mar 21, 2017 12:24 pm

brassfly wrote:Also, my 1 wire setup, I currently have it wired, Ground (GEM side) to VDD and Ground on the sensor, and 1-wire (GEM side) to DQ on the sensor. I can read the serial number off of it and put it in the Temp Degree page, but on the Live Data, it reads nc F. Anyone have any pointers?
You want VDD hooked up to 1-wire 5V. The GEM doesn't officially support using parasitic power mode. It works for some, others it doesn't.
Ben
Brultech Research Inc.
E: ben(at)brultech.com
brassfly
Posts: 19
Joined: Sun Mar 12, 2017 7:45 pm

Re: 2 questions - 1 wire and PT Values

Post by brassfly » Tue Mar 21, 2017 7:24 pm

Thanks for the quick replies!

For the Voltage: Ok, I've cleaned the contacts on the power and PT cables, and blew out ports with canned air. The PT port felt kind of loose, but I was able to plug in. I have the jumper on my board, so I set PT Type to 187 and PT Type to 3. I get 343.3v

On a whim I decided to test the voltage coming out of the PT transformer. 14.99v, with 123.9 at the outlet.


For the 1 wire. I corrected my wiring, and still get the same results. I am able to read the S/N on the sensor, but when I look at 'Live Data' it shows 'nc F'.

Oddly enough, also in the Live Data page, it shows 'nc F' on the first and second sensors. There is only one sensor plugged in or enabled.

I'm not sure if it makes any difference, but I did update the firmware last week so that I could get emoncms working.
Teken
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Location: The Bad Lands

Re: 2 questions - 1 wire and PT Values

Post by Teken » Tue Mar 21, 2017 10:24 pm

Using the base value of 194 / 4 what does the GEM indicate for a line voltage?
Teken . . .

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ben
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Re: 2 questions - 1 wire and PT Values

Post by ben » Wed Mar 22, 2017 10:20 am

brassfly wrote:Thanks for the quick replies!

For the Voltage: Ok, I've cleaned the contacts on the power and PT cables, and blew out ports with canned air. The PT port felt kind of loose, but I was able to plug in. I have the jumper on my board, so I set PT Type to 187 and PT Type to 3. I get 343.3v

On a whim I decided to test the voltage coming out of the PT transformer. 14.99v, with 123.9 at the outlet.


For the 1 wire. I corrected my wiring, and still get the same results. I am able to read the S/N on the sensor, but when I look at 'Live Data' it shows 'nc F'.

Oddly enough, also in the Live Data page, it shows 'nc F' on the first and second sensors. There is only one sensor plugged in or enabled.

I'm not sure if it makes any difference, but I did update the firmware last week so that I could get emoncms working.
I suggest trying Type 194 Range 4 as Teken suggested.

Can you attach a screenshot of your 1-wire setup page on the GEM?
Ben
Brultech Research Inc.
E: ben(at)brultech.com
brassfly
Posts: 19
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Re: 2 questions - 1 wire and PT Values

Post by brassfly » Wed Mar 22, 2017 5:28 pm

Ok, with it set to PT Type 194 and PT Range 4, I get 178.1 volts.

Here is the 1WireSetupPage:
1WireSetup.JPG
1WireSetup.JPG (76.11 KiB) Viewed 2443 times
And the Live Data I'm getting:
LiveData_3-22-17.jpg
LiveData_3-22-17.jpg (81.69 KiB) Viewed 2445 times
Teken
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Re: 2 questions - 1 wire and PT Values

Post by Teken » Wed Mar 22, 2017 5:34 pm

Alright, using a true RMS DMM measure the line voltage from the same outlet as the PT Transformer than change the (Type Value) to bring it as close to the DMM value.

Let us know what that final (Type) value is and if the GEM continues to track closely to the line voltage.

If it does your done . . .

RE: 1 Wire if you select the live tab in the GEM for channel one what temperature is seen? Please post up a screen shot of that tab.


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brassfly
Posts: 19
Joined: Sun Mar 12, 2017 7:45 pm

Re: 2 questions - 1 wire and PT Values

Post by brassfly » Wed Mar 22, 2017 5:42 pm

Ok, with it set to 135/4 I get 124.0 v, which is pretty close. I show 124.2 at the socket.

Here is the screenshot of the live data tab. Still shows "nc F"..
LiveData_3-22-17_2.jpg
LiveData_3-22-17_2.jpg (86.45 KiB) Viewed 2440 times
Teken
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Re: 2 questions - 1 wire and PT Values

Post by Teken » Wed Mar 22, 2017 5:45 pm

RE: PT looks fine you can leave that portion and move forward with the 1 wire. Can I ask you to change the measurement to (Celsius) from F.
Teken . . .

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