DC coupling setting not used

Post your LabVIEW discussions here
Post Reply
cbfsystems
Newbie
Posts: 0
Joined: Wed Nov 27, 2019 7:49 pm

DC coupling setting not used

Post by cbfsystems » Wed Nov 27, 2019 8:25 pm

Hi. We are using a Picoscope 2206a, which I am trying to program using LabView. I call PicoScope2000aOpen.vi, PicoScope2000aSettings.vi, PicoScope2000aGetBlock.vi, then PicoScope2000aClose.vi. Only channel A is enabled. If the scope was previously configured with AC coupling on channel A the last time a measurement was made (during a previous measurement session - PicoScope2000aClose.vi has been called since doing the measurement), then the new measurement is done as an AC coupled measurement even if the current configuration is DC coupling (DC coupling selected in Channel A control of PicoScope2000aSettings.vi). If PicoScope2000aSettings.vi and PicoScope2000aGetBlock.vi are put in a loop, so that the measurement is repeated, then the problem is cleared by setting the coupling to AC and then back to DC. In other words, the coupling is set to AC and then to DC in the current session (since the last time Picoscope2000aOpen.vi was called). If channel A was configured for DC coupling in the previous session, then the correct coupling is used the first time a measurement is made. I can work around this problem by first taking a measurement using AC coupling in the current session and just throwing it away before doing a DC coupled measurement, but this doesn't seem like it should be necessary. Am I doing something wrong, or is this expected behaviour? I am attaching LabView code that demonstrates the problem.
Attachments
Read waveform UI.vi
(16.84 KiB) Downloaded 14 times

AndrewA
PICO STAFF
PICO STAFF
Posts: 258
Joined: Tue Oct 21, 2014 3:07 pm

Re: DC coupling setting not used

Post by AndrewA » Fri Nov 29, 2019 2:18 pm

Hi,

I cannot reproduce your issue with your example vi.
I did have to relink all the sub vi's to our current versions-
https://github.com/picotech/picosdk-ni-labview-examples/blob/master/ps2000a/64-bit-examples/PicoScope2000a.llb
You will also need the current shared folder-
https://github.com/picotech/picosdk-ni-labview-shared

I have attached a modified version that works with current sub vi's above.
Attachments
Read waveform UI_v2.vi
(24.47 KiB) Downloaded 9 times
Regards Andrew
Technical Specialist

Post Reply