Open from multiple processes

C, C++, and Visual C++
Ondrej.Janda
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Open from multiple processes

Postby Ondrej.Janda » Thu Oct 18, 2018 3:27 am

Hi,
I was wondering if it is possible (using the VINT hubs) to open and attach channels (let’s say DI) on one physical hardware (DAQ1200_0) from different contexts/processes. Basically each process reading its own DI (different index).
I know it is not possible with the InterfaceKit 8/8/8, probably because the USB is blocked for the first process that asks for it, but I am wondering if anything changed with the VINT.

Thx,
Ondrej

fraser
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Re: Open from multiple processes

Postby fraser » Thu Oct 18, 2018 9:23 am

I believe this is only possible if you access it over the network.

Since the VINT devices are all accessed through a the VINT hub (which unless you're using a SBC, is a USB device) you wont be able to access it from two processes.

peterpolidoro
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Re: Open from multiple processes

Postby peterpolidoro » Fri Mar 08, 2019 9:20 am

If there are multiple VINT hubs connected to the host computer, is it possible to use a separate process for each hub? Or is the communication with the devices always limited to a single process, even if each hub is a separate USB device?

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mparadis
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Re: Open from multiple processes

Postby mparadis » Fri Mar 08, 2019 10:16 am

If you have multiple VINT hubs, you can access each one with a different program or process. You can do this by setting the serial number of the channel before opening to match the serial of the desired hub.

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Patrick
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Re: Open from multiple processes

Postby Patrick » Tue Mar 12, 2019 11:04 am

This is one of the main use cases for the Network Server. When connecting locally, latency is less then 1ms compared to a direct USB connection, and this allows you to access the same hardware from multiple processes.

-Patrick


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