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Reset CNT, and counting impulses


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7 replies to this topic

#1 Rakete

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Posted 22 February 2013 - 11:44 AM

Hello, Iīm new to Labjack and want to count impulses on the CNT input. I connected a switch and a pulldown resistor. Now i want to reset the counter, but it happens nothing, it stay allways on 29819054. I tried to reset it with LJCounter V1.07, and with Labview, and with Profilab Expert 3.0, and nothing works! And when i toggle the switch, the counter dosenīt increase its value. I run the LJTest and everything seems fine. Driver Version is V1.210, and the Labjack is 1.100. What else could i try? Is the CNT input broken? Maybe, but why canīt I reset it? I never connected overvoltage to it... Please help me! Thanks! Rakete

#2 LabJack Support

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Posted 22 February 2013 - 12:26 PM

Strange. The U12 seems to be operating fine, except that the counter is stuck on a big number. Power-cycle the U12, and make sure only one software application is running at a time. If you continue to see the same problem I suggest you contact [email protected] so we can take further action.

#3 LabJack Support

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Posted 22 February 2013 - 12:27 PM

Also, the digital I/O is normally low on the U12, so you would use a jumper from +5V to create test counts.

#4 Rakete

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Posted 23 February 2013 - 02:17 AM

Hello Support, thank you for your answers! Yes, its very strange! Everything else works fine, except the CNT. Ok, I will try to restart my computer, then the Labjack is resetted, too, and I will start only one software to try it again. Next step will be to try that on an other computer... What do you mean with "the digital I/O is normally low on the U12, so you would use a jumper from +5V to create test counts"? I measured the +5V and the Ground on the input CNT with an oscilloscope to be shure that the Signal is fine. The Ground is really zero, the +5V is 5,12V, and there is no distortion on the signal like chattering. What I else noticed is that when I switch on the STB on the LJCount, then the value of the counter is decreasing one number to 29819053. 32 bit resolution means that the counter can count from 0 to 4294967296. The displayed 29819054 is then not something 2^x. The Labjack is resetted by diconnect the USB and reconnected? There is no switch inside? For a real hardware-reset? And the U12 firmware canīt be updated? What else can I try? Send it back to the store I bought it? But I donīt have warranty any more... Thank you for your support! Maik

#5 Rakete

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Posted 23 February 2013 - 02:28 AM

Maybe itīs because Iīm using an laptop? An quite old one? But there is no difference on USB compared to the RS232 with lower voltage on the port? Then I wouldnīt measure more then +5V on the screw terminal? :unsure:

#6 Rakete

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Posted 23 February 2013 - 02:58 AM

Ok, I checked it with an other PC. No change... What I recognized is a difference between the examples LJlogger and LJcounter: These show different values, 29819340 in LJlogger, and in LJcounter 29819054. And in both I cant reset...

#7 LabJack Support

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Posted 25 February 2013 - 09:50 AM

What do you mean with "the digital I/O is normally low on the U12, so you would use a jumper from +5V to create test counts"?

On our newer devices (U3/U6/UE9/T7), the digital inputs are pulled high (3.3V) internally. So to create counts you would tap a wire connected to GND. But on the U12, the digital inputs are pulled low internally, so to create counts you would tap a wire connected to +5V.


What else can I try? Send it back to the store I bought it? But I donīt have warranty any more...

If you want to send it back to us directly, we can take a look at it. Contact [email protected] to follow-up on that.

#8 LabJack Support

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Posted 20 August 2013 - 09:40 AM

The counter problem here was that the watchdog was stuck on.  See the new item #6 on the U12 Hardware Troubleshooting page:

 

http://labjack.com/s...troubleshooting




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