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I was wondering if there is any way to use the GEM CT inputs to show actual measured mA current, so I might be able to interface the GEM with some of my more commercial / industrial sensors.. the GEM looks like a nice economical way to get to that data and log it.

Many sensors use either 0-1V outputs, or 4-20 mA; some have both. I prefer using current sensing over voltage since it is more tolerant to cabling problems.

Is this possible with an existing CT range & type? If not, is it possible at all with a potential code update?

bigb135 wrote:I was wondering if there is any way to use the GEM CT inputs to show actual measured mA current, so I might be able to interface the GEM with some of my more commercial / industrial sensors.. the GEM looks like a nice economical way to get to that data and log it.

Many sensors use either 0-1V outputs, or 4-20 mA; some have both. I prefer using current sensing over voltage since it is more tolerant to cabling problems.

Is this possible with an existing CT range & type? If not, is it possible at all with a potential code update?

If you can email me the CTs you are looking at using (ben(at)brultech.com), we can take a look at the CT specs and see if they're compatible (and the settings if they're compatible).

Ben

Thanks Ben.
The devices I was looking to read are not CTs; but other sensors with voltage or current outputs.

Specifically right now I am looking to measure CO2 levels to control ventilation systems in my home; this 'ventostat' has both 0-1V and 4-20mA outputs that scale directly to values in the instruments range.

For example, in a given mode of operation for this device, voltage sensing 0 volts = 0 PPM while 1 volt - 2000 PPM; while 4mA = 0 PPM and 20mA = 2000 PPM.

I figured since the CTs output either Volts or Amps, I might be able to get those absolute readings out of the GEM.

bigb135 wrote:Thanks Ben.
The devices I was looking to read are not CTs; but other sensors with voltage or current outputs.

Specifically right now I am looking to measure CO2 levels to control ventilation systems in my home; this 'ventostat' has both 0-1V and 4-20mA outputs that scale directly to values in the instruments range.

For example, in a given mode of operation for this device, voltage sensing 0 volts = 0 PPM while 1 volt - 2000 PPM; while 4mA = 0 PPM and 20mA = 2000 PPM.

I figured since the CTs output either Volts or Amps, I might be able to get those absolute readings out of the GEM.

Ahhh, unfortunately that's not possible as all channels are used to derive true power.