Using SCXI-1166 or PXI-2570 as DPDT

[Crummey]

I noticed that none of the general relay boards have DPDT switches.  Is this just because you can designate two DPDT relays to act simultaneously? As the subject indicates I’m looking at the SCXI-1166 or PXI-2570 boards. 

Thank you,
Jacob

[chericks1]

Hi Jacob,

Although not well documented, the PXI-2570 and SCXI-1166 can both be used in DPDT topologies.  The PXI-2570 as a 20-DPDT, and the SCXI-1166 as a 16-DPDT.  When used in these topologies, each software command in effect connects two SPDT relays.  The two SPDT relays that form the DPDT are always within the same relay bank, and are physically located closely in proximity to one another, which helps to ensure simultaneous actuation.  However, that being said, the two relays are not contained within the same package as a traditional DPDT relay might be.  This is important to note, as the two relays typically actuate simultaneously, but there is a maximum possible delay equal to the spec'd relay operate time between the two relay closures.  The typical and maximum operate times for both the PXI-2570 and SCXI-1166 relays are provided below:

PXI-2570 relay operate time
Typical: 1 ms
Maximum: 3.4 ms

SCXI-1166 relay operate time
Typical: 2 ms
Maximum: 4.4 ms

Let me know if you have further questions!

Chad Erickson
Switch Product Support Engineer
NI - USA

[Crummey]

Chad,

Thank you for your timely response.  As you probably guessed I meant, "... designate two SPDT relays..." in my above message.

My only other question is, can you have both DPDT and SPDT topologies on the same board?  That is, have some relays as DPDT and some as SPDT?

Thank you again,

Jacob

[chericks1]

Hi Jacob,

No, unfortunately you cannot have both DPDT and SPDT topologies on the same board.  However, no matter what topology you choose, you can use DAQmx Switch Close (Open) Relays to actuate multiple relays in the same relay bank at the same time. 

For example, in reference to the SCXI-1166, k0 through k7 are located in the same relay bank.  Providing k0:7 as an input into DAQmx Switch Close (Open) Relays enables you to actuate all those relays with the same software command and with minimized hardware delay.  Most of our switch modules behave in a similar manner.  The PXI-2570 is divided into 5 relay banks: k0:7, k8:15, k16:23, k24:31, and k32:39.

Hope this helps!

Chad Erickson
Switch Product Support Engineer
NI - USA