Communication between cRIO and Kistler Charge Meter

[AnnikaB]

Hello

I am using a cRIO 9076 and NI 9223 Module to get data from the Kistler 5015 Charge Meters with the NI example "User-Controlled I/O Sampling", this works fine. Now I would like to set the parameters of the Kistler Charge Meter with this VI. I have the charge meters connected to my host computer via a USB to COM Cable. I have build a VI on the Host Computer to commuincate with the charge meters and this works fine, too.

But now I would like to integrate this into the VI that runs on the RT Target of my cRIO. The Problem is, that this VI doesn't detect the COM Ports of the Host Computer. My question: is there a way to get the cRIO/RT Target to detect these COM Ports to communicate with the Kistler Charge Meter?

Regards

Annika

[Bob_Schor]

Does the cRIO have a spare USB input?  If so, plug the COM-to-USB device into the cRIO.  You may have to install a Serial driver for the cRIO (I recall needing to do this for a PXI system ...).

Bob Schor

[AnnikaB]

Thank you for your fast reply. I do have a spare USB-input. I plugged in my USB to COM Cable. In MAX I can now see four USB Devices. The amount seems to be right, since it is a split cable for four COM Ports. I don't know how to use these Ports in my RT VI. If I choose Visa Ressource, the only option is to refresh (nothing happens if I choose that option).

If I look at the USB Ressources in MAX and opne the VISA Test Panel, it tells me that there have been errors detected. I can these Errors in "View Attributes" under "Control Pipe" and "Interrupt in Control Pipe". Could this be why I don't see the ressources in RT System or have I forgotten something?

Grateful for any help.

[crossrulz]

Keep in mind that the cRIO has its own OS.  You must install the drivers for your USB-Serial converter to the cRIO.  The hard part is figuring out which OS is used on your cRIO (my searching for 5 minutes didn't find while OS is used) so that you know which driver set to install.

Your cRIO should, however, have a free serial port.  Why can't you just use that?

[AnnikaB]

I wanted to use the USB Port because we need some way control three charge meters. Since we had a 4in1 USB to COM Cable here I tried using this. Concerining the OS, is the OS from the RealTime Target that of the cRIO? If yes, then we have a VxWorks OS. But I don't know if or how you can install external drivers on the cRIO.

After I read your answer I tried to connect only one charge meter via Serial Cable with the cRIO, but nothing showed in MAX.

If you have any more suggestions I would be very grateful.

[xband]

Hi,

I have some general questions about the structure of RT programs on my CRio which communicate with external instruments through ethernet.  I have all of my external instruments communicating but am concerned about network errors causing problems with the application if communication were to be lost.  Currently I'm not running error wires through these vi's because I'm interested in the speed of my application and parralel loop processing.  My main RT vi is communicating with the FPGA on the controller through FIFO's.  This project also has a EtherCat expantion chassis communicating through shared variables.

Since this thread was fresh I was hoping you might point me in a good direction as it is a similar topic.

Thanks,

Jim

[MichaelJakob4]

Hi AnnikaB

Just for your information, to shrink down your measurement chain 😉

There is a new cRIO charge amplifier module from Kistler available. No separate charge amplifier is needed!

Have a look at: http://www.ni.com/product-documentation/2726/en/ or www.kistler.com/5171A.

That would also solve your COM port problem because it is controllable from the FPGA like the common cRIO modules via SPI communication.

Best regards,

Michael J.

[ZX81]

The 5171A looks pretty awesome.  I don't see a price, but odds are, it's much cheaper than development time to get the USB/Serial converter to work.  Installing device drivers in embedded hardware can go smoothly once in a while, but not often enough.

Another option is NI 9870.  It's under $700, including cables.  If you're really lucky, you could get the USB/Serial working for less, but you could easily spend a whole day fighting it, and not get it working.

[AnnikaB]

Thank you for your advices. I already thought about your ideas before, but we have two problems. We can't spend that much money at the time, and our cRIO is full. Plus, the Kistler 5171A is too slow for our purpose. We have the NI 9223, since we need a Sample Rate of 1 MS/s.

Does anyone know if FTDI Chips are at all compatible with the VxWorks OS? I only found articles for the Linux OS.