Is there a way to address multiple cards with one command?

[Phil E]

Hello,

I am wondering if there is a way to address multiple SCXI switch cards with one command.
I have (4) SCXI-1127 cards in a chassis.

I am currently using the commands:

status = niSwitch_Connect(card1, "com0", channel)
status = niSwitch_Connect(card2, "com0", channel)
status = niSwitch_Connect(card3, "com0", channel)
status = niSwitch_Connect(card4, "com0", channel)

But this takes about 1 sec to complete, and I am looking to speed up the switching time.

Is there a way to use 1 niSwitch_Connect command to make all 4 cards ( or all cards ) perform the same niSwitch_Connect command?

Or, is there a way to initialize all the cards under one ViSession number?

Thank you,

[Guy Ferraro]

Phil E,

1s to make these 4 calls is very long. We have benchmarked the time for 1 call and 1.8ms without wait for settle and 11.5ms with wait for settle what you can expect. The time depends on what is running on your machine and the speed of the processor.

You can use one call to access all 4 devices. DAQmx connect has a "multiple device" personality that you can use to close multiple channels on different devices. The improvement will not be dramatic using a single call.

[Phil E]

I am using a 4 slot SCXI-2000 chassis, commands are sent via the RS-232 port. (19.2Kbps)

The program is written in visual basic in an excel speadsheet.
I can actually hear the clicking of the relays opening and closing
one board at a time and it takes about a second to complete all four boards.

Can you think of a reason it might be taking so long to complete?
All four commands are sent in sequence without pauses.
The CPU is fairly modern >1Ghz.

[JasonWhite]

I think that the reason for the delay is due to the RS-232 communication to the SCXI-2000 chassis.  The communication speed over RS-232 is much slower than what you would get with a directly cabled chassis (for example, to a PCI-4021 switch controller, a DMM, or a DAQ board) or even with a USB interface (for example, the USB-1359).

If the speed increase is important and you are able to switch from RS-232 to USB, I recommend moving to the USB-1359.  It will work with your SCXI-2000 chassis.

[Phil E]

FYI

After buying the SCXI-1359 USB card, I've found that it doesn't work with SCXI-2000 chassis, only the SCXI-1000.
The datasheet didn't list which chassis it works with, only which cards it supports, and it supports my SCXI-1127 cards.

Actually, the new NI software doesn't even work with the SCXI-2000 chassis in serial mode. I had to revert back to the old software.

[Guy Ferraro]

Phil E,

I confirm that the USB-1359 works with the SCXI-2000. In fact I just set it up and I was able to actuate relays on the SCXI-1127 in a couple of minutes.

Here is what I did:

1) Inserted the SCXI-1127 in the SCXI-2000

2) Connected the USB-1359 to the back of the SCXI-2000

3) Turned on the SCXI-2000

4) Inserted the USB plug to my computer

I was able to see "found new hardware" and I was able to go into MAX and click on test panel for the SCXI-1127 to actuate relays

Note the SCXI-2000 will be recognized as an SCXI-1000 which doesn't make a difference.

Please try the steps above and let me know how you found out that the SCXI-2000 doesn't work with the USB-1359.

Guy Ferraro

Switch product Support Engineer

NI-USA 

[Phil E]

Hello,

I did the steps you mentioned and I did get the computer to install the chassis as an SCXI-1000.

However, when I tried to communicate with it in MAX either with auto-detect cards or setting up the SCXI-1127 modules to 1 x 64, I would get a communication error.

I tried various settings but wasn't able to get it to work.

I called your tech support and they told me that the SCXI-2000 wasn't supported.

I thought that maybe the serial interface on the SCXI-2000 was interfering with the USB adapter.

Can you think of anything you did in MAX to get the card to communicate?

Thank you,

[Guy Ferraro]

Phil E,

When the USB-1359 is detected, it creates an entry in MAX, creates the SCXI-1000 in NI-DAQmx Devices with an SCXI-1127 in Slot 4. You do not need to autodetect anything, the USB does everything for you, Do you see the SCXI-1127 created when you plug the USB cable to your computer?

To change the topology, right click on the SCXI-1127 just created and select property. I have nothing else connected to my 2000 except the 1127 and the 1359 on the back.

We do not mention the SCXI-2000 in the USB-1359 documentation but it works. What is the Service Request Number you created when you called Tech support. I need to correct the information they have. Thanks

[Phil E]

Hello,

I tried re-installing the USB Module on my SCXI-2000 chassis and re-installed the software.

No Luck. I still had the same errors. ( see attachment )

I had ordered an SCXI-1000 chassis last week and it came in today.
I plugged in the cards and cables and voila, no problems. Everything works great.

Maybe I have and old firmware in my chassis that is incompatable?
My serial number is AED8D2 on the SCXI-200 chassis.

If you can't think of a way for me to use my old chassis, I guess I'll have to keep the new one.
At least my speed problems are a thing of the past.
This arrangement switches in under 1/10 sec for all four boards.

[Guy Ferraro]

Phil E,

This is not related to a firmware issue in any way. The error is the one I get when I turn off my SCXI chassis right before resetting the module. If you chassis is on then I do not know what could be wrong.

I am glad we did fix the original timing issue.