VISA Ethernet connection to multiple instruments

[jmsS]

I would like to connect to multiple Ethernet instruments (three in my case) via VISA. Is it possible to establish separate VISA sessions with all instruments in parallel and obtain data from all three instruments simultaneously?

Thanks,

Julian

[Dennis_Knutson]

Yes, you can have three connections in parallel. Simultaneous is maybe and how strictly you define simultaneous. The best way to get simultaneous readings is to trigger all of them at the same time.

[jmsS]

Ok, if I get you correctly I can communicate to all three instruments in parallel and are not restricted to sequential communication. However, communication would not be simultaneous (exactly at the same time). What would you say would be a typical time difference between execution of a command (e.g. read instrument data) if I send this command to all three instruments in parallel in LabVIEW? 50-100 ms would be acceptable for me.

[Marco_Brauner]

Hi jmsS,

I guess it should be in the range of a couple of ms, so sending a command to 3 open sessions within 50 - 100 ms should work.

regards

Marco Brauner NIG

[nyc_(is_out_of_here)]

---

@jmsS wrote:

Ok, if I get you correctly I can communicate to all three instruments in parallel and are not restricted to sequential communication. However, communication would not be simultaneous (exactly at the same time). What would you say would be a typical time difference between execution of a command (e.g. read instrument data) if I send this command to all three instruments in parallel in LabVIEW? 50-100 ms would be acceptable for me.

---

It is possible to trigger 3 instruments simultaneously. Once the instruments have finished making their measurements, you can take however long you wish to retrieve the measurements. This is the proper way to do things.

[jmsS]

---

nyc wrote:

It is possible to trigger 3 instruments simultaneously. Once the instruments have finished making their measurements, you can take however long you wish to retrieve the measurements. This is the proper way to do things.

---

I know that a proper hardware trigger would be the best to achieve a simultaneous measurement of all instruments. Unfortunately, there is no suitable hardware trigger available in my case.

Or do you have a better idea to implement a kind of software trigger than the parallel instrument readout described above?

[nyc_(is_out_of_here)]

---

@jmsS wrote:

---

nyc wrote:

It is possible to trigger 3 instruments simultaneously. Once the instruments have finished making their measurements, you can take however long you wish to retrieve the measurements. This is the proper way to do things.

---

I know that a proper hardware trigger would be the best to achieve a simultaneous measurement of all instruments. Unfortunately, there is no suitable hardware trigger available in my case.

Or do you have a better idea to implement a kind of software trigger than the parallel instrument readout described above?

---

http://forums.ni.com/t5/Instrument-Control-GPIB-Serial/same-command-to-multiple-instruments/m-p/3621...

[jmsS]

---

nyc wrote:

http://forums.ni.com/t5/Instrument-Control-GPIB-Serial/same-command-to-multiple-instruments/m-p/3621...

---

Thanks, but I hardly understand anything of that thread - only that it is about GPIB low-level commands. Does this really apply to my case of VISA Ehternet communication?

[nyc_(is_out_of_here)]

---

@jmsS wrote:

---

nyc wrote:

http://forums.ni.com/t5/Instrument-Control-GPIB-Serial/same-command-to-multiple-instruments/m-p/3621...

---

Thanks, but I hardly understand anything of that thread - only that it is about GPIB low-level commands. Does this really apply to my case of VISA Ehternet communication?

---

Did you read the post by Makoto in the thread?