SCXI-1131 Signal problems (V)

[Mikey2]

Hello, i'm fairly new with labview and data aquisition systems. I'm having some problems that i have not encountered before and could use some help.

I'm attempting to hook a gas monitor up to our DA system/software.

We have an SCXI-1121 with a SCXI-1131 module for my connection to the gas monitor. The signal from the monitor is 4-20mA. By adding a 250 ohm resistor, i'm trying to obtain a 1-5V signal.

When setting the parameters and scaling factors in the Measurement and Automation software, the DA isn't detecting any voltage change.

The signal coming from the gas monitor has been double checked, and i've even tried hooking the module right up to an external DC voltage supply. In measurement and automation, i have all the correct parameters checked and have used the same setup many times in detecting millivolt signals.

I have even tried using a spare SCXI-1321 and it does the same exact thing. They both have worked fine in the past which makes me believe its not a SCXI-1321 problem. While the SCXI-1321 isn't working, our SCXI-1102 module does work (TC readings). That makes me believe its not a chasis problem either. The only thing left would be a software issue.

Maybe a sample rate issue, or something needs to be adjusted when dealing with higher voltages than the millivolts we have always used? Hopefully all that made some sense. Thanks!

Mike

[Raajit_Lall]

Hello Mike,

You mentioned that you are using an SCXI-1131, could you please double-check that. What kind of driver do you have on your system? It would also help if you told us the operating system of the computer. What are the parameters that you are setting and what are the scaling factors that you are using in Measurement and Automation Explorer? You mentioned that you hooked up and external power supply, did you read any voltage when you had the power supply hooked up? Could you also please elaborate a little on "the DA is not detecting any voltage change"? Does this mean that it is actually reading a voltage that is constant and not changing even if the input voltage is changing?

Regards,

Raajit L

[Mikey2]

Thanks for the response,

I have sinse fixed the problem i had encountered. It turned out that the gain setting for the channel was set so only low millivolt signals could be detected properly. I increased the gain until i could detect my 1-5V signal. All is well for now!

Mike