Use of CAN and DAQmx modules on the same chassis

[vix]

I've been using DAQmx devices for several years, but this is the first time I need to use CAN.

I have some questions:

• Is it possible to use one DAQmx NI-9132 module and one CAN NI-9862 module on the same cDAQ-9185 chassis?
• Is it possible to use them from two different executables on the same PC (i.e. executable #1 uses NI-9132, executable #2 uses NI-9862)?
• Is it possible to use NI-9862 without NI XNET drivers? I mean, sending and receiving data from a PLC (and not from an executable on PC)?

Thanks in advance

[Hooovahh]

Great questions.  The cDAQ-9185 is a dumb chassis.  The thing is great for when you want to expand the IO of a system.  Let say you write a Windows program running on a PC.  And you are out of USB ports but want to add IO.  You can use a USB hub, but you can use a router, and have it access devices on a network remotely.  In MAX and LabVIEW it will appear as if this hardware is locally connected to the PC.  This is also useful if you want to do DAQ stuff when the PC and the system are farther apart than a USB should be.  Also great for laptops that don't have much IO capabilities.

The chassis itself has no intelligence.  It can't run programs, it is just a way of adding IO to a system.  Think of it like one of those USB chassis, just using ethernet instead.  You can't run a program on the USB chassis.  There are chassis that do have a processor, ram, and storage that can run programs, and control the IO without needing an additional computer.  These can be running real-time Linux, or and embedded version of Windows.  The cDAQ-9132 for instance can run an embedded Windows 7, or Linux RT.  In the Windows variant you can load up the normal LabVIEW IDE, plug in a keyboard and mouse and use all the IO that are plugged right into it.  With Linux RT you need a second computer as the development machine which then deploys code to it from LabVIEW.

To answer your question.

1) Yes you can use the NI-9232 and NI-9862 in a single cDAQ-9185 chassis.  The online configurator allows it, and there aren't that many cDAQ modules that can't go in every chassis.  The really old single slot ones did have some limitations but I don't know of any recently.

2)  I don't think an ethernet chassis like this one can be controlled by two EXEs.  A chassis like this needs to be reserved to be used.  It is an ethernet device after all and multiple computers might be trying to control it.  So I think these get reserved or locked, then used, then unlocked.  The USB chassis don't have to worry about this, and you can have two EXEs, one controlling one card, one controlling another.  I haven't used one of the ethernet chassis in a while so I might be wrong here.  Still what is wrong with having one program?

3) The XNet device must be controlled using the XNet API, just like DAQmx devices must be controlled with a DAQmx API.  If you have an embedded device, like the cDAQ-9132 I mentioned earlier, then you can code an application that listens for communication from a PLC, and then have it take action like controlling IO.  I don't interact with PLCs often, but when I did I think I used raw TCP, but there are probably other options.

[vix]

Hello @Hooovahh

thank you very much for your answer.

It's useful to clarify the situation, and probably NI solution is not the best one (in this case).

I already have a cDAQ-9185 with a couple of modules, controlled by an exe running on a PC.

Now I need to add CAN FD to the system, controlled by PLC (if possibile).

Up-to-date, Siemens doesn't have CAN FD board for its PLC and so I need to find an ethernet CAN FD gateway (ETH to CAN FD).

My first idea was to add a module to the existing cDAQ, but I was quite sure that it's not possible to have it controlled by the PLC without any NI drivers.

The "two EXE" is only a first step to demostrate if the scenario would be feasible or not. And it's not.

Since every device should reserve the whole chassis (and not the module), it's impossible.

Using another cDAQ-9181 could be an idea, only if there is documented ETH protocol to use 9862 withotu XNET drivers (protocol to be implemented inside PLC).

But I don't think it's possible.

[Hooovahh]

Yeah it doesn't sound like it is possible the way you want.  You could buy a second chassis, and connect it to a PC running Windows.  Then write a program that reads the PLC communication, and sends it out over CAN FD making your own gateway.  Or like I said get an embedded controller and have it do the same thing headless.