Can I output a voltage from an NI9237?

[jgh@AET]

Hello.  I am using Labview Signal Express with a cDAQ9172 and NI9237 module to acquire strain data.  I would like to use the default excitation voltage for the strain gages as well as independently output a 10V signal from the 9237.  Can this be done?  Is there another way I can get a voltage output from this setup without buying a separate voltage output module or voltage supply?  I want to supply the 10V to a potentiometer and acquire the output of the potentiometer by using a NI9219 module that I already have.

Thanks in advance,

Justin 

[Brad_K]

Hi Justin,

The NI 9237 hardware doesn't support different excitation voltages on different channels. However, there are two ways you can measure the resistance of a potentiometer using just the NI 9219. If the resistance is between 0 and 10 KΩ you can use resistance mode. Otherwise, you may want to consider acquiring a voltage ratio using half bridge mode and doing some math to calculate the resistance.

Brad

[jgh@AET]

Thanks Brad.  Actually I am using a potentiometer now to measure resistance (angle) of a rotating shaft and strain (torque) with a strain gage on the shaft.  The problem is as the gear teeth on the shaft and potentiometer mesh, the resistance does not increase linearly.  Therefore, I want to try a non-contact magnetic angle sensor which requires a voltage input and produces a voltage output that is linear with shaft rotation.  So, I will need a voltage source and a way to acquire the voltage output from the angle sensor.  I actually would prefer a way to sample simultaneously with the 9237 at a higher frequency than the 9219's 2hz at high resolution.  So, two questions really: 1)  What do I need to output a voltage using a cDAQ9172 with Signal Express software.  2)  What module would allow me to sample voltage simultaneously with the 9237 at the frequencies the 9237 is capable of (I think the lower limit is 2000hz)?  I thought the 9219 would do it, but the accuracy is poor unless I set it to "high resolution" and then the sampling frequency is way too low. at 2hz.

Thanks a lot,

Justin