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Model 2790 SourceMeter Switch System Reference Manual
Message exchange protocol
Two rules summarize the message exchange protocol:
Rule 1. You must always tell the Model 2790 what to send to the computer.
The following two steps must always be performed to send information from the instru-
ment to the computer:
1.
2.
Rule 2. The complete response message must be received by the computer before another
program message can be sent to the Model 2790.
RS-232 interface operation
Sending and receiving data
The RS-232 interface transfers data using eight data bits, one stop bit, and no parity. Make
sure the controller you connect to the multimeter also uses these settings.
You can break data transmissions by sending a ^C (decimal 3) or ^X (decimal 18) charac-
ter string to the instrument. This clears any pending operation and discards any pending
output.
You can break an RS-232 transmission of buffer readings by pressing LOCAL and then
EXIT. The next command to send buffer data (i.e., TRACe:DATA?) will start at the begin-
ning, rather than where the transmission was halted.
Baud rate
The baud rate is the rate at which the Model 2790 multimeter and the programming termi-
nal communicate. Choose from these available rates:
•
•
•
•
•
•
•
The factory selected baud rate is 9600.
When you choose a baud rate, make sure that the programming terminal that you are con-
necting to the Model 2790 can support the baud rate you selected. Both the multimeter and
the other device must be configured for the same baud rate.
Send the appropriate query command(s) in a program message.
Address the Model 2790 to talk.
19.2k
9600
4800
2400
1200
600
300
10-17
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