Switch Hardware and Software

cancel
Showing results for 
Search instead for 
Did you mean: 

PXIe-2527

Solved!
Go to solution

I have a pretty basic question about the PXIe-2527 32-Channel, 300 V Multiplexer Switch.  In the documentation it states that this multiplexer can be setup as a 1-wire dual 32 x 1 multiplexer.  Does this mean that the two 32 x 1 multiplexers are completely independent from one another (meaning that I can control them separately and make different connections)?  Also, for my application I intend to have one of the 32 x 1 multiplexers route 24VDC to 32 test points, and the other 32 x 1 multiplexer will route 32 test points back to a signal conditioner.  For the 24VDC multiplexer I will need to route the 24VDC to multiple test points at the same time.  With this module is it possible to make multiple connections with a single multiplexer, or are you limited to one output connection at a time?  Thanks for the help.

0 Kudos
Message 1 of 6
(7,035 Views)
Solution
Accepted by topic author JGar

Hello,

 

That is correct, working in the 1-wire dual 32x1 topology means that you will be able to control independently each multiplexer. I would like to suggest working with the test panel of this board in MAX. There you will be able to select the topology and verify that you can control each one separately.

 

Regarding your second question, you will be able connect multiple channels to COM working in the Independent Topology.

 

Regards,

 

MCOTO

0 Kudos
Message 2 of 6
(7,013 Views)

Thank you for the information.  I haven't ordered the PXIe-2527 yet because I wasn't sure it would work for my application.  But based off of what you have told me it seems that it will work perfectly.  Thanks again.

0 Kudos
Message 3 of 6
(6,981 Views)

So I ordered the PXIe-2527 thinking that you could do multiple connections in each individual 32x1 matrix, which I found out isn't the case.  When doing some additional research I found the following diagram for the Independent topology:

 

Relay.png

 

What this picture shows is that the relays that switch for channels 0 through 31 are double pole single throw (relays K0 through K31), and a single pole double throw relay (KHLSELECT0 and KHSELECT1) is on the output of both COM0 and COM1.  KHLSELECT0 and KHSELECT1 allow the double pole single throw relay to be treated as two independent single pole single throw relays by routing either CH+ or CH- to COM.  The caveat is that only one of the inputs in that pair can be at the output at one given time.  Another side note.  When in dual 32x1 topology, KREF1 wires COM1MINUS to 1WREF1 and KREF0 COM0MINUS to 1WREF0.

 

So what all this means is when in dual 32x1 topology, only one input can be connected to COM at a time due to the KHSELECT limitation described above.  When in dual 32x1 topology the two multiplexers are independent from one another and can be controlled seperately, but with only one connection to COM at a time.

 

On the other hand, the independent topology allows multiple connections to COM at a time, but it is in pairs only.  For example, if you connect CH0 to COM0 the following connections are made:  CH0+ to COM0+ and CH- to COM-.

 

I post this in case anyone else has the same question I did and isn't sure about how the dual 32x1 topology operates.

0 Kudos
Message 4 of 6
(6,844 Views)

JGar,

 

So what all this means is when in dual 32x1 topology, only one input can be connected to COM at a time due to the KHSELECT limitation described above.  When in dual 32x1 topology the two multiplexers are independent from one another and can be controlled seperately, but with only one connection to COM at a time.

Using traditional channel connections you can only have a single connection coming from a channel to a com output as it will claim that com0 is used.

 

You should be able to use relay control to enable multiple inputs to connect to the same output. Closing K0 and K1 will allow ch0 and ch1 signals to connect to com0.

 

Thoughts?

Frank,
National Instruments
Software Group Manager
0 Kudos
Message 5 of 6
(6,829 Views)

Frank,

 

I have been messing around with the relays since I saw your post and I think that I have it doing what I require now.  By energizing KREF0 and KREF1 and making sure that KBC01 is disconnected, I essentially put it in the dual 32x1 multiplexer mode.  I then close the appropriate K ch relay and use the KHSELECT relay to swich either the + or - to the COM.  In using the relays, I can make multiple connections to COM as you mentioned.  Thanks for the idea.

0 Kudos
Message 6 of 6
(6,818 Views)