Problems connecting to 2 different USB devices

[c.zink]

Hi,

I am trying to initialize 2 different powermeters, but for the second device the connection always fails.

The interesting part is, that if each powermeter is initialize separately the connection works without problems.
I also tried for each type to connect 2 powermeters of the same type without problems.

Here are some facts about the powermeter
- Ophir NOVA 2 using the official (but old) version of LabView VIs
  it has the VISA address: USB0::0x0BD3::0x0333::NI-VISA-50003::RAW
  This device connects always without problems

- ThorLabs PM100USB using also the official LabView VIs

  it has the VISA address: USB0::0x1313::0x8072::P2001716::INSTR

  If I try to connect to this device after the connection to the Ophir is established. The VI of the ThorLabs powermeter

  gets stuck when the VISA address is send the first time to a standard VISA WRITE VI as part of the ThorLabs init VI.

  This VISA WRITE VI is marked as running and only resolves if the Ophir powermeter is disconnected.

I would appreciate every hint on how to solve this problem!

Greets

Christof

[JohannesM]

Hi,

The visa Vis are multithreading enabled. You should be able to connect to several devices at once. Are there any resources or VIs shared between those drivers?

I unfortunately have no access to the ThorLab Driver, but I recommend using the simplest case of communication with the device, ergo open specified resourse with open VISA, read single value (maybe in a loop) and close the connection. Do that for two devices.

Does the error occur?
If not, there is very little I can do, you should contact the programmer of ThorLab.