Ni 9208 Connections

[VultureMan]

I am switching my old SCXI 1000, 1100, 1300 for a new NI eDAQ 9174.  I am using temperature (8) and pH transmitters (8 powered loop) and have an NI 9208 with a NI 9923 terminal block.  Where I had 2 wires (+ and -) coming from each transmitters it was easy to connect to the 1300.  With the NI 9208 I need to pick between the A1 side and the Vsup side.  My best guess is the A1 side has the + wire connected to it.  Do I connect one - to the COM pinout or does it connect to the corresponding Vsup? 

Thanks!

[FinchTrain]

Hi VultureMan,

Your inclination is correct. For your reference, take a look at the statement below the pinout diagram in the 9208 Getting Started Guide on page 9-10.

"Each channel has an AI pin to which you can connect a current signal. The NI 9208 also has 17 Vsup pins, one for connecting an external power supply, and one for each channel. There are also four common pins, COM, that are internally connected to the isolated ground reference of the module."

NI 9208

http://www.ni.com/pdf/manuals/375170b_01.pdf

Regards,

Finch Train

[VultureMan]

Thanks for the response Finch Train.  I have been through the documentation as well.  I guess the question is if i connect the + wire from my transmitter to A10, then the - wire goes to Vsup 20?  (The transmitters are already powered).

[FinchTrain]

Would you mind posting the model or a link to the transmitter that you are using? It may be most efficient to connect your external supply to the Vsup 19 pin and feeding power through the module. You would connect the return line of the power supply to the COM pin and the - wire of the transmitter to COM as well so they reference the same ground.

[VultureMan]

I am using transmitters from Omega.  I am using 4 TXDIN70 (2 channels each for a total of 8 channels) and 8 PHTX-014.  Both are running on 24 volts, but the PHTX-014s are power looped.

[FinchTrain]

Hi VultureMan,

I believe since you are making current measurements you would connect the + side to the AI channel, and - side to the available COM ports that reference the isolated ground in the card.

Regards,

Finch Train

[VultureMan · Accepted solution]

Okay, it is working now.  This is what I did.  I ran 24v power supply positive to the Vsup side.  24v power supply negative to COM.  Ran the + side of each transmitter to a Vsup pin.  The negative of each transmitter to an AI pin.

Thanks for your help!

[ola2]

Please, how did you run the 24V power supply to the Vsup because I'm facing the same challenge. 

Did you by an adaptor to connect to power supply and then connect to Vsup on the NI 9923?

[AvatarAang]

Do you have a power supply yet?

You will have to wire the positive end of the power supply into the Vsup pin. You can find which pin number is the Vsup pin of your device by finding the device pinouts on the manual. This will not be the manual for the 9923, since it is a terminal block; it will be the manual for the actual module.

[VultureMan]

Powered Loop

I did buy a Mean Well 24 volt adaptor.  It was fairly inexpensive from Allied Electronics.

Run the 24V positive to 19 on the terminal block

Run the 24V negative to 9,10, 28, or 29 on the terminal block (whichever is easiest to get to)

The VSUP pinouts (20-27 and 30-37) will supply + voltage to the transmitter

AI pinouts (1-8 and 11-18) are the return lines that 9208 reads the signal. (- from transmitter)

I run 8 powered loop transmitters (pH) and 8 (temperature) that are not power looped, but run on 24volts (same adaptor different leg).  The supply + in didn't matter to those transmitters.

I hope that helps a bit!