Problem Controlling PXI-2503 Switch through the IVI-C Switch API

[VRMan]

Hi,

I'm writing an application to control a PXI-2503 switch in 1-wire mode using the IVI-C Switch API in order to route signals to a PXI-4060 DMM.

According to the programming instructions, I should be able to create a path from the "ab0" channel to a channel like "ch10" by calling IviSwtch_Connect( "ab0", "com0" ) to connect "ab0" to "com0" and then calling IviSwtch( "com0", "ch10" ) to connect "com0" to "ch10". However, after the program makes those 2 functon calls, the DMM doesn't get the correct signal.

When I use the NI Switch Soft Front Panel application to connect "ab0" to "com0" and then connect "com0" to "ch10", then the DMM gets the correct signal. Does anyone know what the Soft Front Panel tool does differently?

Thanks in advance to anyone who can help.

VRMan

[Travis_W]

VRMan,

Make sure that you have configured your 2503 to be in the 1-wire 48x1 topology...

Other relays that need to be closed for ch10 to make it to ab0 are  "bc01" and "1-wire".  Check out the hardware diagram for the 2503 which can be found by going to Start>>Programs>>National Instruments>>NI-Switch>>Documentation>>NI Switches Help, then browse to Devices>>2503>>PXI-2503 Hardware Diagram.

When you use the SFP or program with LabVIEW, you have the option to initialize a switch with a certain topology.  For the 2503 1-wire 48x1 mode, this automatically changes "bc01"," bc02", "bc03", and "1-wire" to the correct positions.  Check to make sure that the same is done when using the IVI-C driver you are working with.

Let me know if this doesn't solve the problem, or if you have any more questions.  Best of luck on your application.

Regards,
Travis W

[VRMan]

Hi Travis,

The 2503 switches are configured in 1-wire 48x1 topology. The first thing the software does after initializing the switch is to ask it for its various channel names and the channels "ch0" through "ch47" were discovered. However, the channels "bc01", "bc02", "bc03", and "1-wire" did not show up. Is there any way for me to query the state of those 4 relays through the IVI-C API?

Thanks,


VRMan

[Travis_W]

VRMan,

As long as your switch is initialized with the proper topology, the bcX relays I mentioned shoudn't be the problem.

After you conect ch10 to com0 and com0 to ab0, try checking the status of those connections from software to verify that the driver thinks they're properly  connected.  Also, make sure to handle any errors from the driver calls you are making.  What do the results show?