can read but cann't write by VISA

[byz]

I use “Instrument I/O assistant” in LabVIEW 8.5 in window XP to control (communicate) with Vue-MVseries Laser Diode controller.

Now I am able to read the laser diode temperature by entering cmd “adlt” through “Query and Parse”. However, I can only read number (for example 2134) in “String” formate instead of “Number” formate. I also got problem to express the read string with a “text inds”, when I run my labVIEW program, it appears: “Syntax error: i0.00000”, in stead of the number.

In addition, I also get problem to command the laser current by enter a number through “write”. When I click “run this step” for writing a number to the controller, there isn’t any error sign appears. However, the laser current was always 0, the current wasn’t been controlled. As I checked, there isn't any thing wrong with the laser set.

Could you please tell me how to resolve the two problems. It is more important for me to be able to control the laser current.

Thank you.

[Dennis_Knutson]

You obviously can write to the instrument because you say you can issue the command to get the reading. Are you sending anything else besides the numeric when trying to control the current? It is next to impossible to generate an error on a write so the fact that you don't have an error is meaningless.

You have not provided any code, the manual for the instrument, or even the communication type.