Can i short two relays on SCXI 1127 module? What are pros and cons of shorting two or more than two relays?

[ateem]

I am using SCXI 1127 module to test some short circuit paths and want to know if i can connect two or more channels to COMMON at the same time which means i'm essentially shorting them.
Thank You

[Guy Ferraro]

Yes you can connect multiple channels to COM (which I hope you are referring to OUT0+ and OUT0- on the terminal block). This can only be done in Indepedent Mode.

[ateem]

Thanx for your reply. I have one more related question.How can i configure input channels on a per-channel basis without using MAX? I need to change between 1 wire mode and 2 wire mode frequently and i want to do that programmatically. So i think i may need to close other switches too like HLSELECT and AISENSE !

[Guy Ferraro]

If you are using the SCXI-1127 in independent mode the wire mode setting in MAX is irrelevant. This setting is only used when the SCXI-1127 is not used in independent mode.

In Independent mode you are free to activate any relay that you like. You are responsible for setting Hlselect and 1Wire according to the wire mode desired (1-wire or 2-wire)

Refer to this support document:
http://sine.ni.com/apps/we/niepd_web_display.DISPLAY_EPD4?p_guid=B45EACE3E95956A4E034080020E74861&p_node=DZ52331&p_submitted=N&p_rank=&p_answer=&p_source=External

If you are not using independent mode, you cannot set the wire mode on a per channel basis programmatically. You need to close the Switch session and open a new one with a different topology;16x1, 32x1, or 64x
1 which will set the switch in 4, 2 and 1-wire respectively.

[JasonWhite]

Also, if you have a switch controller that is supported under DAQmx (such as the 4021), you can configure the 1127 as a DAQmx device. The benefit is that with NI-SWITCH 2.0 there are now both 1-wire and 2-wire topologies that can be selected at init time. This makes it easy to switch between the two modes programmatically without having to manually manage things in independent mode or having to configure the channels in MAX.