Message Exchange Protocol; Sending And Receiving Data - Keithley 6430 Instruction Manual

13-16 Remote Operations
Multiple response messages
If you send more than one query command in the same program message (Multiple com-
mand messages), the multiple response messages for all the queries are sent to the computer
when the SourceMeter is addressed to talk. The responses are sent in the order the query com-
mands were sent and are separated by semicolons (;). Items within the same query are sepa-
rated by commas (,). The following example shows the response message for a program
message that contains four single item query commands:
0; 1; 1; 0
Response message terminator (RMT)
Each response is terminated with an LF (Line Feed) and EOI (End Or Identify). The follow-
ing 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 SourceMeter what to send to the computer.
The following two steps must always be performed to send information from the instrument
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 SourceMeter.
RS-232 interface operation
NOTE

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 SourceMeter also uses these settings.
You can break data transmissions by sending a ^C (decimal 3) or ^X (decimal 18) character
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."
Send the appropriate query command(s) in a program message.
Address the SourceMeter to talk.
The programmable aspects of RS-232 operation (baud rate, data bits, parity, and
terminator) are configured from the COMMUNICATION option of the Main Menu.
See Section 1, "Main Menu. "