Rs232 - Controlling instruments

[orrca2112]

I need to write commands to an instrument using rs232. I just need to control the temperature of a temperature chamber.

http://www.testequity.com/documents/chambers/Modbus_Packet.pdf
the link above shows an example of the kind of packets I need to send.

I need some help writing binary commands to the instrument.

this is what I want to do: use a proc to merely change the temp of the chamber

proc change_temp {temp} {
# send packet to change temperature
}

Can anyone help me with code for writing to the device?
I know how to configure the serial port, I just don't know how to send the command for writing to the instrument.

[Nuno João]

orrca2112 wrote:

I need to write commands to an instrument using rs232. I just need to
control the temperature of a temperature chamber.
...

Take a look at the help file for TCL's "binary" commmand.