Accessing hardware board with two VIs simultaneously

Hello,
I have a NI BNC-2090 board that I use to interface with a multimeter (which I get my data from) and an ion gauge (which needs to have its filament current regulated and held constant). I have a VI which I've written that performs both the data acquisition and current regulation, but it can only do one of these tasks at a time, which is undesirable because the filament current drifts when the data is being gathered.
In order to prevent the filament current from drifting, I want to create two standalone programs that I can run in parallel, so that the filament current can be regulated continuously and so that data can be acquired on demand. I've attached two programs which I've made to do this.
Each of the attached programs does its job very well. The problem I have arises when I try to run them both simultaneously. The error I get is Error -50103, which tells me the specified resource (my board, if I understand this correctly) is reserved.
I tried to be a little more explicit in my task creation and I also tried defining global virtual channels in MAX to no avail.
Any help would be greatly appreciated.
Regards,
Ali
Solved!
Go to Solution.
Attachments:
Standalone DAQ.vi ‏40 KB
Standalone PID Feedback.vi ‏51 KB

Ali H. wrote:
Brian,
Having all my reads in one task and all my writes in another makes sense, especially after I learned that the board has only one A/D converter.
What I'm struggling with now is how to restructure my set up. Is there a way to share tasks between VIs and keep the VIs distinct like I want so that I can run them individually or together as I need? Or will that requirement force me to incorporate the VIs I posted as subVIs of another VI which passes the same read and write tasks to both subVIs? (If this is unclear, see attached png; the case structures are so I can choose which subVIs run and the while loop is there so I can turn them on and off).
Thanks.
Yes, By adding in a Special type of Action Engine I've dubbed a "Resource Module" as a hardware access layer for yor task. Since the Module is not re-enterant any vi can call the Resource Module without fear of causing DAQmx errors but, the second caller will wait for the first call to finish. Here is an example notice that it keeps the resorurce discriptor (in this case a DAQmx Digital Out Task) on a Shift register to avoid the need for the caller to know what is going on with the resource (saves wires too).
Jeff
Attachments:
Attenuator.vi ‏30 KB

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