NI 9402 frequency measurement

[Pedze]

Hi Forum

I have: Dasylab 11, NI cDaq with a 9402 high speed digital input/output module, Newest version of Daqmx driver

I am using the 9402 module to measure the frequency of a squre pulse signal.

1)

But when I run the setup in Dasylab, I get the same values for each block - the signal is constant for every block.

However when I test the setup in MAX (Daqmx driver software) I get different values for each sample in the block. As it also should be.

Does dasylab only read the first, last or take an average over the samples in the block or what goes wrong?

Rasmus Nissen

FLSmidth

[CJ_Butler__DASYLab_Pro]

How have you configured the task? 

How have you configured the DASYLab NI-DAQmx Counter input? 

There are a lot of things that need to be configured to get this to work. 

[Pedze2]

Hi CJ

The task is configured as follows:

In MAX: "Counter input" - > "Frequency" -> [choose counter]

In the seup I then enter: "Signal input range": 2 kHz to 20 kHz, "Measurement Method": 2 Counters (high frequency)

"Acquisition mode" : Continuous Samples, "Samples to read": 2048, "Sample Rate": 3,2 kHz.

In Dasylab:

I want this task to run along with a different task which measures analog input signals. This task works with a NI analog input module.

This task is aslo configered with block size of 2048 and a sample rate of 3,2 kHz

"Modules" -> "Input/Outputs" -> "NI-DAQmx" - "Counter module"

In the setup of the module: "Time base settings": Here I choose the analog input task. If I choose "Driver", I get a timing problem between the two tasks.

I have also tried to set the frequency task to "1 Sample on Demand" for Acquisition mode. However I still get a constant value for each block (the block size determined by the analog inout task)

BR

Rasmus Nissen

[Pedze]

Hi

I am missing some replies, please.

Rasmus Nissen

[MHa]

Hello Rasmus,

sorry for time delay to check your problem. I have simulated your device situation, see pictures from the appendix. I found that the NI 9402 "continuous mode" is not yet detect from DASYLab driver and always handle via "1 sample polling". I would like check the DASYLab driver sources for the problem. Please contact the DASYLab support (http://www.mccdaq.com/) with your contact address. I would like start to fix the problem, if possible and contact you later.

Best regards,

MHa 

[Pedze2]

Hi MHA

I have been in contact with my suplier of Dasylab. He says that it is only a "graphical error" that dasylab does not seem to recoinize "continious samples".

...?

BR

Rasmus Nissen

[MHa]

Hello Rasmus,

this information is not correct. There is a adaption problem between NI-DAQmx API interface and DASYLab NI-DAQmx driver itself. I have today started to check (fix) the problem on NI-DAQmx and or DASYLab side.

Best regards,

MHa

[MHa]

Hello Rasmus,

the NI NI-DAQmx group and DASYLab group have checked together the problem. Under LabVIEW had the same results but with more error details.

error: -201323

Possible reason(s):
Sample Clock timing is not supported when using a two-counter measurement method.  Use a one-counter measurement method, or use a different timing type.

The DAQmx Assistant for some reason is not reporting this error for the configured task. My guess is it is not configuring the sample clock timing at all. It could be it was supposed to disable the timing options in this case but did not do so. In any, the hardware unfortunately does not support sample timing for this timer configuration ( I think newer cDAQ chassis may not have this restriction).

The problem is now checked for an future bugfix for a next NI-DAQmx API version. Release date for this is unknown for the moment.

[Pedze2]

Hi MHa

Thank you very much for your help.

I do need to understand two things:

1) This "bug" you are describing, does it explain why I have my problems, or is it a completly different issue?

2) Will I have to wait untill the new version of DaqMX is released before my problems are fixed?

Best regards

Rasmus Nissen

[MHa]

Hello Rasmus,

for 1) This "bug" you are describing, does it explain why I have my problems, or is it a completly different issue?
-> This is "your" bug. DASYLab NI-DAQmx driver analyze every "incoming" MAX task. We receieve for your task a sampling rate = 0.0 (not possible) and change the task type to "one sample". But this is not useful, what is do to
   - bugfix for NI-DAQmx API itself, here is the base from problem
   - bugfix for DASYLab NI-DAQmx driver -> we would "stop" this type of tasks which returns sampling rate = 0.0, so it's not usable under DASYLab

for 2) Will I have to wait untill the new version of DaqMX is released before my problems are fixed?
-> Sorry, I can't give you any release date for bugfix and for which version. This is outside from my "working area".

Please contact the www.mccdaq.com and here "CJ" (CJ tell me = "MHa") for this problem. Let us know your email address and I would like contact you for next steps for this problem.

Best regards
MHa