NI-9361 Counter Card Not reading below 2.9v

[TomElecTestEng]

hello,  looking for some help/advice...?

i'm currently running a Turbocharger rig with a passive variable reluctance sensor,  which is operating from 1v lowest speed to 24v highest speed.  however i'm finding the NI-9361 card wont pick up until the probe is 'putting out' over 3v. (read from a PICO scope) 

did some digging into the Cards the 9361 indicates it operates 0-24V in a single ended conection (this is what im using) 

i dropped a desktop Hz generator onto the input signal to test the cards input range, and i'm finding the card wont read when the voltage is below 2.9v (even in NI MAX)

i'm running the signal into 2 seperate 9361 cards also so i'm certian its not the specific card causing the issue. 

has anyone had experiance with this before at all? could anyone advise?

Kindes regards 

Tom 

Electrical Engineer 

i can give as much information across as needed, if ive missed anything 

[crossrulz]

For digital signals, you have to have a set voltage (threshold) before it can be considered a "high".  It looks like the NI-9361 has a programming threshold range (NI-9361 specifications).  So I'm guessing the threshold is currently set to around 3V.  If you need it to be lower, then program it to be lower.

[TomElecTestEng]

Thankyou very much crossrulz,

apologies for asking a silly question, i've not dealt much with NI equipment at all, this is very much a learning curve.

how would i go about programming the thershold range in NI Max? 

Kind regards 

Tom

[crossrulz]

I'm not familiar with this card either.  But I would guess there is a setting in MAX to set this threshold.  In LabVIEW, I would be digging through property nodes to find the setting.

[santo_13]

Looks like you can configure the threshold from the FPGA interface,
https://www.ni.com/docs/en-US/bundle/c-series-reference-and-procedures/page/criodevicehelp/crio-9361...

[ZYOng]

Use CI.ThreshVoltage property for NI-DAQmx.

Reference: Acquiring TTL Digital Signal With NI-9361 in LabVIEW

[TomElecTestEng]

thanks very much for your time & help i will go look into this, this morning 

Kind regards 

Tom