Communicating with two SR830 Lock-in instruments using one GPIB-USB interface

[AJN]

Hey All, 

I need to talk to two SR830 Lock-in instruments at the same time. They both seem to have the same GPIB Primary address. Hence i am unable to communicate with them using a single USB-GPIB cable. The lokckins are connected with individual GPIB cables. 

Is there a way to talk to them simultaneously. Please let me know. 

Thank you. 

[Albert.Geven]

Why talk to them at the same time?

You probably want to arm them in the same mood and then trigger them to execute the measurement at the same time. Afterwards reading both measurements.

But you need to set the addresses different to connect them to one bus.

[AJN]

I need to collect the first ans second harmonic at the same time.  Thus i need to talk to them at the same. Can we execute the measurments as you mentioned. If so how would we do it?

[Albert.Geven]

As I said. Give them separate addresses and use Group Execute Trigger for triggering at the same time.

GPIB is a bus with command lines and one combination is reserved for triggering intruments that are prepared to be triggered.

Your assumption that you need them to be at the same address is simply wrong.

[AJN]

No i do not have to use them at the same address absoulutely not!!!

I do not know how to change the address. The instruments do not show up in the NI-Max under Devices  as i am using a USB to GPIB 488.0 To connect to all the instrument. 

I can see the instruments on the VISA INteractive control. Can you tell me how can i change the address in this condition.

[Albert.Geven]

You can change the address on the SR830 itself. It should be in te manual. You probably have them at the default addres now and in the first pages of the manual they tell how the GPIB address can be changed inside the instrument by the frontpanel. You cannot do this from the PC side. It has to be done on the instrument itself.