Test and Measurement Forum

Hi.
I am now using Labview 8.0 , DrDAQ and picolog recorder 5.0.
I find that when I open the example in Labview, data can be taken once only. Then there is error when opening picolog recorder , too.
I need to restart my computer in order to use the picolog recorder again.

Also, when I open NI Measurement & Automation program, there is no detection of DrDAQ


Please help.

Regards
John

Hi John

The LabVIEW example is a simple example intended to get you started. You can modify it to take more than one reading if you wish.

I believe that NI Measurement & Automation Explorer is only for NI hardware.

I'm not sure why you are having problems with PicoLog. Only one program can access the hardware at any one time.

Robin

Dear Robin,
The main probelm is that when I run the example program in Labview, I can only get one result. When I run it again, all readings are zero.
Also, there is error when I open picolog after closing Labview.
I need to restart computer in order to use picolog.

I think there is a crash after I run the example program.

( When I open the picolog, an error : DrDAQ Driver V3.6 pico.sys not found.
After pressing "OK", a second error occurs : DrDAQ LPT1 pico.sys not found)

Hope you can help me.
Thanks for your attention

Regards,
John

Here I directly use drdaq_single.vi
I still ahve the same problem...
There is a reading at the begining and then no reading afterwards.

BUT after I try serval times, I can use picolog with no problem without restarting the computer.

But there is still only 1 reading everytime I open the Labview...

Hi John

I misunderstood your problem.

The problem of PicoLog crashing can be solved by changing the 'call library function' node to call drdaq_labview_single rather than drdaq_labview_single-2.

We need to investigate why the function is only returning values after its first call. It may be a driver issue or to do with the fact that the DLL function was originally created for a much older version of Labview.

Regards

Robin

Hi Robin

Thanks gor your reply.
But I don understand the 1st point.
What should be changed?

Regards,
John

Hi

In drdaq_single.vi, double click on the central block (this is a Call Library Function Node that is used to access functions in the DLL). Under function name, there is a drop-down menu and drdaq_labview_single-2 will be selected. You should change this to drdaq_labview_single.

Robin

ok i get this
Thanks

Hi

This example does not use drdaq_labview_single. It continually updates the display when you run it.

Hope it's useful

Robin

Robin
Thanks for your great help.

But I find a small problem is that if I want to take sample per second by adding wait function connecting with "1000" constant, then the program works with my expection except that it cant be stopped by clicking the stop button. After this the DrDaq doent work and restart computer is needed for further use.

Hi

Try this. Right click on the stop button and select "mechanical action" and change to "latch when pressed" (bottom left).

Hope this helps