very first returned sample is always the same

[mael15]

i have a very strange problem with my usb-6210.

i read two channels with 16bit and i have a constant input signal with values variing between 2300-2600. now the very first sample read is always exactly 13108 on the second channel. after the first sample, the following are read correctly.

the first channel reads correctly right from the start.

how can that be?!

thanx for your thoughts.

[mael15]

to be more exact: i read two channels in blocks of 250 scans and in every scan the first value of channel two is always exactly -13108.

[AndreasStark]

What version of DAQmx are you using?

Does this also happen, if you are measureing at a slow sample rate?

Does this also happen if you run a DAQmx example?

Regards,

[mael15 · Accepted solution]

hi andreas,

thanx for your input! while trying to gather the infos to reply to you, i found the error. 

i am using wxWidgets and read 16bit values from daqmx. to store the values in a buffer, i use a wxInt16 array. turns out, this array gets initialised with -13108 values for reasons i cannot imagine.

hope this info helps someone...

thanx again.