A problem on serial communication with an instrument

[Jiwei]

I tried to control the Agilent 34970A, the data acquisition/switch unit, through RS232 interface.
I connect the computer and instrument with the RS232 cable, then start the instrument, then start
the computer, but there is no RMT or ADDR displayed on the instrument display screen.
I programmed a VI: "VISA configure serial port"-->"VISA Write(The command is "*RST")"-->"VISA Close".
There is no respond after running it.
Then I wrote another program: "Serial Port Init"-->"Serial Port Write"-->"Close Serial Driver"
A RMT will display on the instrument screen after "Serial Write" execution, and no other respond.
(When I connect the instrument to another computer, start instrument, then start the computer,

there will be a RMT on the instrument display screen).

I am sure that the instrument is good, and is set to RS232 interface, the cable is right(verified),
and the parameter such as baud rate is the same as the computer. (I am using LabVIEW 6.1)


Can anyone give me an explain about my problem? Thank you!"

[Nick_Storton]

Hi Jiwei,

Make sure that the instrument and serial port set up match on:

1: Number Start / Stop Bits.
2: Number Data Bits.
3: Parity.
4: Baud Rate.
5: Flow Control.

Hope this helps,

Nick

[Dennis_Knutson]

In your other post about the identical problem, I asked if you are using the driver available for the instrument. Its now obvious that you're not. Download it from here and save yourself a lot of trouble. The first problem I see is that you're not adding a terminator to the command. This is required for serial communication and is explained in the instrument's programming manual. The driver will do this.

Message Edited by Support on 01-23-2007 02:59 PM