03-23-2015 10:42 PM
Hello,
I have:
I created one Switch Executive Virtual Device to manage them all. I exported the configuration, and see that the listed settling times are:
I measured how long Switch Executive waits for settling, but got strange numbers:
Why does Switch Executive decide to wait 18 ms or more? I expected it to wait 4 ms (the longest settling time in the config), or perhaps 8 ms (disconnect first and wait 4 ms, then connect and wait 4 ms). Am I misunderstanding how the wait VI works?
Thanks in advance for any insights!
03-24-2015 11:51 AM
JKSH,
With a 2534 matrix (1.8 ms) and a 2576 mux (3.0ms) I did the same test and on my test machine where I had a single connection on each module that was disconnected and another different connection was made in the Connect and Disconnect VI. This same test produces the following numbers:
No connections - 0-2 ms
Connections on just the 2534 - 2-3ms
Connections on both - 3-4ms
Is the Disconnection specification always the same?
What version of NI Switch Executive are you running?
Perhaps there is some additional SW that is causing additional jitter on your system?
03-24-2015 11:05 PM
Hi Frank,
Thanks for looking into this. It's odd that you're getting different numbers from me.
If it makes any difference, here's more info about my hardware:
I've also attached my Switch Executive config file.
> Is the Disconnection specification always the same?
When I wrote "If I don't make any connections/disconnections, niSE Wait For Debounce.vi waits 18 ms", I meant that the "Switch?" input is FALSE, so that niSE Connect and Disconnect.vi isn't called at all. (Refer to the VI snippet in original post.) Calling niSE Wait For Debounce.vi by itself, without niSE Connect and Disconnect.vi, made it wait 18ms.
This suggests to me that niSE Wait For Debounce.vi doesn't query the modules to see if they've settled or not, but instead just calculates a safe period to wait.
> What version of NI Switch Executive are you running?
NI Switch Executive 3.6
> Perhaps there is some additional SW that is causing additional jitter on your system?
No other software was running, except for the usual background Windows processes, and the test VI I showed in the original post.
Also, the results weren't jittery -- when "Switch?" is FALSE, "Wait time (ms)" consistently shows 18 ms. No fluctuations.
03-26-2015 02:43 PM
This suggests to me that niSE Wait For Debounce.vi doesn't query the modules to see if they've settled or not, but instead just calculates a safe period to wait.
I just verified that we simply call the IVI SWITCH Wait for Debounce function on all modules in the Virtual Device regardless of the previous connection.
AKA if you have a connection on Device 1 and 2, Wait For Debounce will wait for debounce on device 1 and then on device 2.
If however you have a connection on Device 1 only. Wait for debounce does the following
Given that you have a total of 9 devices it could be that its making WFD calls to these other devices adds up to a delay of 18 ms, but I doubt it...
What version of NI-SWITCH do you have?