Picolog and ADC11/12 Samplerate is not set correctly!

pako · Post by **pako** » Wed Sep 10, 2003 10:58 am

In order to test a hardware converter that I have designed to convert +-5V input to 2.5 V input as the ADC 11/12 uses, I have found out that the Picolog program doesn't set the samplerate for the ADC11/12 correctly!

Here is what I do:

I use a signalgenerator as input to the ADC11/12, set at 10HZ, +-5V(remember I use my own hardware converter).

Then I set the Picolog program to sample at 1ms intervals for 500 samples, which gives me 5 periods over 500ms of signal from my signalgenerator.

Then I set the Picolog program to sample at 10ms intervals for 50 samples, which gives me 0.5 periods over 500ms NOT 5 periods!

Then I set the Picolog program to sample at 5ms intervals for 100 samples, which gives me 1 period over 500ms NOT 5 periods!

I used Picolog release:5.09.4

WHAT is going on here??

Regards Palle Koch

markspencer · Post by **markspencer** » Thu Sep 11, 2003 8:14 am

Hi,

I have just repeated the experiment that you explained, and each and every time I got I ran the test with the three different time intervals and sample number I got a 5 cycle wave form, in the graph view.

I used the ADC11 connected to the parallel port. A signal generator with an offset so that I could see the full amplitude between 0-2.5 volts and had a 10 Hz signal.

So that I can see what you are getting please email me the .plw files for each test to:

tech@picotech.com

Please also state is you are using parallel or usb and the OS you are using. Once I have this additional information I will rerun the test using your .plw files and try to emulate it again.

Best regards,