controlling an individual relay in 2575

[tsiltu]

Hi,

I try to control NI 2575 module in 98x1 mux topology using niswitch_32.dll. However when I want to control one individual relay using niswitch_relaycontrol function. I got an error saying that the parameter for the function is invalid. I successfullly got the device handle, and I am sure that the relay name I use is correct. What may be the reason for the problem? The function and the parameters I use is shown below:

niSwitch_RelayControl(resourceName, "K0", niSwitch_32.RelayPositionValues.NISWITCH_VAL_CLOSED)

thank you

Message Edited by tsiltu on 02-05-2007 02:51 AM

[Brian F.]

Hello tsiltu.

The niSwitch_RelayControl function is only compatible with switch modules that support independent mode.  Independent mode allows the user control over specific relays.  The 2575 module does not have an independent mode which is why the k0 command is not working as you expect.  Instead of using this function, I would recommend using the niSwitch_Connect and niSwitch_Disconnect functions to control which channel is being passed to the com port in your switch. 

Good luck on your application and please post again if you have further questions.  We would be happy to help!

Brian F
Applications Engineer
National Instruments

[tsiltu]

Hi Brian,

Thank you for your help. I want to ask you  one more question, I see that I am not able to use relay_control function to control the relays individually. But is there any other way to connect more than one relays to the common channel at the same time?

Thank You 

[Brian F.]

Hello tsiltu. 

Almost all PXI modules, when configured in a multiplexer topology, have mutually excluded channels. This means that two channels can't connect to a single COM at the same time. The PXI-2501 and PXI-2503 are the only exceptions.  Since your PXI-2575 only has multiplexer configurations, there is no way to connect more than one channel to the common channel at the same time. 

Brian F
Applications Engineer
National Instruments

[cs1]

Hello,

I had the same question and found these posts.  Is there any hardware limitation that prevents the 2575 multiplexer from functioning as a matrix?  Logically it should be possible, but the software/firmware is probably the sticking point.  Has anyone found a way around this?

We're using this to switch low-level, low-current signals so loading would not be a problem.  A matrix was not part of the original project scope, but requirements have changed, and using different modules will be very disruptive with all of the rewiring needed.

Thanks,

Clyde

[lis@jiang]

Hi cs1,

Thanks for the question.  Just a tip:  new questions should get more attention from users if you start a new thread rather and reply to an old one.

The 2575 multiplexer cannot be used as a matrix, and this is actually going to be hardware limited.  Multiplexed switches are composed of SPMT switches where as matrix switches are completely different in that any row can connect to any column.

Your best bet here is to purchase a matrix switch and do the re-wiring.

Thanks,

Lisa