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Wrong number of ACKs received

U3 LJTDAC

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4 replies to this topic

#1 RRachev

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Posted 08 July 2014 - 02:07 AM

Hello everyone,

 

I am trying to run a code as downloaded from the labjack website (...VC6_LJUD/Any Device/LJTDAC), however when the program tries to communicate with the LJTDAC module it gives the following error:

"Communication error with LJTDAC module, wrong number of ACKs received."

 

From what I've read from previous posts is might be a problem due to an older version of the drivers, however I could not follow the links given in those treads to update the driver.

 

Thanks in advance.

 

PS: I am using a LabJack U3-LV.



#2 LabJack Support

LabJack Support
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Posted 08 July 2014 - 04:19 AM

Driver packages are available here: http://labjack.com/support/software

 

Also, make sure your U3 is up to date: http://labjack.com/support/firmware/u3



#3 RRachev

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Posted 15 July 2014 - 06:50 AM

Thank you for the response. However, even after I managed to build and run the example, the same error pops up, when I  execute another code. I am using C# and the idea of the code is to gradually increase the output voltage of DAC-A, and when a button is pressed to take a reading from analogue input, while continuing to increase the voltage. It does display the reading, but after it gives the same communication error with LabJack module and does not continue to increase the voltage.

 

Code:

 

while ((Environment.TickCount - time) < t1)

{

LJUD.ePut(u3.ljhandle, LJUD.IO.TDAC_COMMUNICATION, LJUD.CHANNEL.TDAC_UPDATE_DACA, (Environment.TickCount - time) * v_cs / t1, 0); 

 

if(read_int<display_int)
   {
   LJUD.eAIN(u3.ljhandle, 2, 0, ref Rec_Volt, 1, 0, 0, 0);
   RS_text.Invoke(new Action(() => RS_text.Text = Convert.ToString(Rec_Volt)));
   }

}

 

After the 'if' condition is met and reading is displayed the program does not continue running until the 'while' condition is fulfilled, rather stops and displays:

Error: Communication error with LJTDAC module, wrong number of ACKs received The thread 0x12ec has exited with code 259 (0x103).

 

Thanks in advance.



#4 LabJack Support

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Posted 15 July 2014 - 08:32 AM

Is the behavior the same whether the LJTDAC is plugged into the U3 or not?

 

Does the test utility work?

 

http://labjack.com/s...ories/ljtickdac



#5 RRachev

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Posted 15 July 2014 - 10:32 AM

I figured out the mistake. I thought 0 was default value for negative channel AIN  {LJUD.eAIN(u3.ljhandle, 2, 0, ref Rec_Volt, 1, 0, 0, 0);} , but apparently it's not and it was interfering with the ports where the LJTDAC module was connected, causing it in a way to disconnect and could not be found.

 

I changed it to 3 { LJUD.eAIN(u3.ljhandle, 2, 3, ref Rec_Volt, 1, 0, 0, 0); } , hoping that if I ground FIO-3 it would only give the voltage of FIO-2, didn't quite work out the way I thought. Then I changed it to 31:

   LJUD.eAIN(u3.ljhandle, 2, 31, ref Rec_Volt, 1, 0, 0, 0);

 

as described:

 

"If the negative channel is set to anything besides 31/199, the U3 does a differential conversion and returns a pseudobipolar value. If the negative channel is set to 31/199, the U3 does a single-ended conversion and returns a unipolar value. Channel 30 puts the internal voltage reference Vref (~2.44 volts) on the negative input of the ADC." - http://labjack.com/s...ers-guide/2.6.1

 

Thank you for the help.





Also tagged with one or more of these keywords: U3, LJTDAC

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