Drive trigger line by multiple devices (or connect many trigger lines)

[mimomar]

Hey all,

Here's what i've been trying to do recently and am starting to get frustrated. So basically I want multiple devices to drive the same trigger line. Thought this mighyt be a problem for my application. Let me rephrase with a question that would give me the optimal solution. I have an PXI-6653 card on my PXI-1045 and what i want to do is say:

Send triggers generated on 2 lines (say PXI_Trig0 and PXI_Trig1) to a 3rd line (say PXI_Trig2). effectively I want the line PXI_Trig2 to get triggered whenever either of the first 2 get triggered. (If you want to think of this in a binary logic way, I want something like "Trig2 = Trig0 OR Trig1" , so I will get a rising edge on 2 whenever 0 or 1 have a rising edge)..

 If it try to send (connect) both Trig0(source) and Trig1(source) to Trig2(destination) using NISYNC vi's, it wont work because it will say that Trig2 is already in use after connecting to one of the others (0 or 1).

Note that I dont want Trig0 or Trig1 to change, i.e i dont want to send trig0 to trig1 and then send trig1 to trig2

PS: when i say "send trig1 to trig2" i mean connect trig1 as the source and trig2 as the destination in the NISYNC connect trigger terminal VIs.

What can be done about this? Smart workarounds? or some way of overriding the fact that i cant connect multiple lines to the same destination line??

[JÞB]

A basic "or" gate can be simulated by placing two 1KOhm resistors in series between the two trigger outputs and connecting the center point to your destination.

Idealy, you would use an external "or" gate (7432N) to avoid noise and maintain system timing

[mimomar]

i am asking if i can programatically do this in labview without the use of any external devices or connections.

[Lars_L]

Hey mimomar,

Could you give us a little more background as to why you are trying to share the connection between these trigger lines? Most likely you will have to implement some sort of external connection to achieve this, but if I had more details as to the hardware that you are trying to synchronize with this setup then we should be able to give you the best solution. Let me know!

Regards,

Lars