Keithley 2520, User Manual, Page: 155 / 329

10-16 Remote Operations Model 2520 User’s Manual
Response message terminator (RMT)
Each response is terminated with an LF (Line Feed) and EOI (end or identify). The fol-
lowing example shows how a multiple response message is terminated:
0; 1; 1; 0 <RMT>
Message exchange protocol
Two rules summarize the message exchange protocol:
Rule 1. You must always tell the Model 2520 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. Send the appropriate query command(s) in a program message.
2. Address the Model 2520 to talk.
Rule 2. The complete response message must be received by the computer before another
program message can be sent to the Model 2520.
RS-232 interface operation
NOTE The programmable aspects of RS-232 operation (baud rate, data bits, parity,
and terminator) are configured from the COMMUNICATIONS SETUP menu
accessed with the COMM key.
Sending and receiving data
The RS-232 interface transfers data using 8 data bits, 1 stop bit, and no parity. Make sure
the device you connect to the Model 2520 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, or by sending an RS-232 break condition (holding the transmit
line low for >11 bits). This clears any pending operation, discards any pending output, and
returns a “DCL.”
Baud rate
The baud rate is the rate at which the Model 2520 and the programming terminal commu-
nicate. Choose one these available rates:
• 57600
• 38400
• 19200