6020E Counter measurement slow

[Peter D'Hoye]

Slow performance using the 6020E counters to measure pulsewidth.
Using traditional DAQ (device not supported by DAQmx)
Using hardware triggered measurement.

After configuration, doing the following:
- program
- loop until no longer armed
- read count and check for overflow

This cycle takes 100ms to perform on a signal that pulses every 10ms (pulse between 1ms and 8ms)

As I understand, after programming, the counter arms itself on a falling edge (hardware trigger) and measures the next pulse passing by. So this would mean worst case 20ms + communication overhead. Either this hardware triggering isn't working or the overhead is 80ms?

Any help appreciated A LOT!

Peter

[JorisV]

Hi,

a overhead of 80 ms, seems very slow. The data transfer with this daqpad is ofcourse slower than with a PCI-bus but this seems too much.

Did you try this with LabVIEW? If yes, did you try it with Measure Buffered Pulse (DAQ-STC).vi? You can find it in Find Examples: Hardware Input > Counters >DAQ-STC. This example is ideal and optimized to do a continuous pulse width measurement.

Regards.

JV

[Peter D'Hoye]

Thanks JV,

Unfortunately, we want to read the pulswidth of the first pulse to come (hardware triggered), then do some things with it, do some other stuff in parallel and then read some more. So buffered reading isn't going to help much.

We started from the 'Measure Pulse (DAQ-STC).vi' sample, changing it to do triggered measurements and tweaking timeout and errorhandling to our needs.

It does seem that the 6020E has been a bad choice for the our task at hand (many single reads), as we've had performance issues in analog readings as well. Probably have to dump it all and go for some PCI solution.

Peter

[JorisV]

Hi Peter,

I agree that for single point Analog input tasks, the Daqpad 6020 is slow. It's limited to 50 Hz.
A PCI version would be more usefull for you then.

Regards

JV

[khillo99]

hello,
I am a trainee and I work with Ni daq 6020e, I want just to generate a clock signal with a variable frequency between 50 et400 Hz, I have find an example which makes the same thing but when I change the frequency I have always the same value (460hz) thank you to help me if you have an idea.
my address mall is: machkour99@hotmail.com
cordially