06-15-2017 02:27 AM
Hello,
I want to read 100+ registers from Modbus. How does VISA do that? If it was 100 queries at 8 byte each its already 12800 out of 19200 bit ber second? Will VISA update all the valoes in the I/O server with a range query regardless if I later on extract the shared variebles in a different order?
Thanks for your replies!
06-15-2017 04:11 AM
06-15-2017 05:11 PM
there are gaps inbetween and some values I cannot access. How does I/O host deal with that? Does it at least work out how many are grouped? On the Distributes System manager it seems to be ok, they seem to update at least twice per second. Once its in a shared variable, I then its in computer memory.
06-15-2017 07:19 PM
06-15-2017 07:54 PM
If the I/O servers are actually using VISA behind the scenes, you might be able to use I/O trace to see how they are interacting. If this is a concern more than a curiosity, you might want to consider using the Modbus API which will let you define the requests.
06-15-2017 08:13 PM
it seems to be a default, but in realyty it uses as much as it needs. Sometimes its set to 9600, which should not get me anywhere>.
I set the distributed systesms manager to 100ms, still working.