"different devices with same address"

[tony.olivieri]

Labview(or myself) is having difficulties communicating with two different instruments that apparently send and receive similar commands, Both instruments are from Agilent Tech, One is a power meter modual (81635A), the second is an Agilent tunable laser(8164A), they need a physical distance between them. When I connect them via GPIB cables they register as one device on a single GPIB address, so when a simple "IDN?" query is done both device respond resulting in a message "HHEEWWLLEETTTT--PPAACCKKAARRDD.....".  so for example, if I was to send a "turn laser on" command, it will send to both laser and power meter, and of course I receive and error due to the fact that the power meter modual will not be able to comply.

Each device operates perfectly when connected alone,  The driver is the same for both devices(HP816XX). How do I tell Labview that there are two different instruments connected and therefore set them with two different GPIB address's?

Any help or hints would be appreciated, 

Thank you,

[Dennis_Knutson]

I'm confused. According to this, the 81635A is a module that you plug into a mainframe such as a 8164A.

[tony.olivieri]

Yes it is, the 81635A can be plugging into the 8164A, however my power meter module is plugged into a stand alone power meter(8163A), that is some distance from the laser source. Regadless I did actually stumble apon the solution.

I "assumed" the GPIB address's were designated to instruments by MAX. But as I discovered today that the GPIB address's are actually designated by the instruments themselves, Whomever used this power meter module before me set the GPIB address coincidently to be the same as my laser source. Now I just need to figure out to generate a Logarithmic trend-line equation to best describe my data....  

But thank you for effort to understand my little problem.