Error using optical counter with NI 9203, 9221 or 9422

[OptiDan]

I'm using an Omron optical sensor (model E3F2-DS10C4-N 2M) to measure the frequency of a spinning disk.  It ouputs pulses of 16V @ 22mA. 

First I tried a NI 9203 to measure the current and determine the frequency, but this had a lot of crosstalk between the channels (about 35%). 

Then I tried a NI 9221 to read the voltage pulses.  This got rid of the crosstalk and yielded a pretty clean signal.  In fact I could get a good freq from either of my two channels.  But when I tried to monitor both freqs simultaneously, LabView gave erratic results (freq alternated between 0, the actual freq, and infinity).  I could run a LabView program monitoring either channel by itself, but not both at once. 

Then I tried a NI 9422 digital counter module.  This one I can't get to read at all.  Various errors. 

Why so much cross talk on the NI 9203?

Why can't the NI 9221 monitor two channels at once (it has 8)?

Does the NI 9422 need a clock or something else to run properly?

[samantham]

Hello,

For the 9203, you stated that you had 35% crosstalk.  How are you configuring the Current Input task?  What is the range for current?  You noted the value of 22 mA, thus I will assume your range is 0-20 mA.  Is the task configured to this range?

How do you have the 9221 wired?  Are both signals connected to the COM line?

The 9422 is a Digital Input module … since the Omron is an optical proximity switch, are you looking to acquire a digital signal?  0 Volts is a low and 16 Volts is high for the acquired signal.  This model can do a Digital Input (DI) or Counter Input task.  You will not need a counter to do a DI task.

Please describe your desired application in further detail and also take a look at the attached documentation.  The Operating Instructions have figures that show proper connections for wiring.  The KnowledgeBase explains a couple of concept that might relate to the bouncing signal on the 9221 and the crosstalk on the 9203.  Please let me know if you have any questions or concerns after reviewing the attached documentation.

Product Manual:  NI 9201/9221 Operating Instructions and Specifications

Product Manual:  NI 9201/9221 Operating Instructions and Specifications

Product Manual:  NI 9422 Operating Instructions and Specifications

KnowledgeBase: Troubleshooting Unexpected Voltages, Floating, or Crosstalk on Analog Input Channels

[RotoMoto]

Hi,

I have a similar issue, I have an Omron optical sensor (Part# E3X-DA-S) we use for giving a once per rev. pulse indication to measure speed. This is physically wired into the NI9211 card, how do I design my block diagram architecture in LabVIEW to most efficiantly measure and log this signal as speed?

As you can probably tell I am somewhat new to LabVIEW, therefore in addition please can you also help me with the following?

• I would simply like to read a digital input digital signal, directly in to a boolean indicator from the DAQ Assistant and then log each channel, though this doesn't seem to be as simple as I had imagined, please can you help?

Thanks

Craig