Proper way to wire in a frequency input to a counter channel?

[larboc]

I have a pxie-6355 that I am trying to use to measure the frequency output of a sensor. I'm testing it with a function generator first and am struggling with the update rate/resolution trade off and I'm pretty sure it's because I'm not setting up the channels correctly.

My current setup: C0 is setup to read frequency, with a min frequency of 1 hz and max of 100,000 (the default)

I have two conductors from the sensor: signal ground and signal.

Signal ground is wired to a digital ground, signal is wired to pin 37 (counter source). None of the other inputs to counter 0 are used.

Target is running at 200 Hz, thermocouple input cards are at 10 hz.

Sensor full scale output from 0Hz to 10,000 hz

Resolution of the signal in Veristand is 1 Hz, but the update rate is only once per second. If I increase the min. frequency value to 100 Hz, then the resolution of the signal gets reduced to 100 Hz intervals, but it seems to be coming in at 100 Hz.

"what do you want to do?"

Measure a frequency between 100Hz and 10,000Hz with 1Hz resolution and at least 100Hz update rate.

I've searched and not come up with anything helpful, I'm assuming I'm missing some fundamentals of counter channel operation.

[davidraj]

To where are you deploying the veristand engine? 

It should be deployed in a real-time system if you want determinism like that. 

[larboc]

Pxie-8100

[Mike.B]

It sounds like you're trying to set correct Frequency Channel Properties for a Counter Input in VeriStand. However, if you check out the note in the above Help page, it mentions that you might get a more reliable accuracy or update rate if you employ a Pulse Measurement Channel. Per the note, only X Series DAQ, such as the 6355, are capable of this since they have the pulse counter measurement option.

[larboc]

I tried moving the A pulse wire to the gate input (CTR 0 GATE 3 (PFI 9)) and set up veristand for pulse measurement but the update rate was extremely slow (1Hz) and none of the "Channel settings" in veristand affected the measurement. When I changed measurement types I made sure to delete the channels and re-ad them as pulse measurement.

And I am using a PXIe-6355

Thanks for any help!

[okubik]

I think it would help if you share  minimalistic SDF file that reproduces the issue. We can have a look into to check how you set-up the system timing

[larboc]

Here is one of the SDF's we're using now and it works okay, but the resolution of all the counter channels are compromises between resolution and update rate.