Model 6517B Electrometer Reference Manual
Section 11: Remote operations
6517B-901-01 Rev. C / August 2015
11-15
Command execution rules:
1. Commands are executed in the order that they are presented in the program message.
2. An invalid command generates an error and, of course, not be executed.
3. Valid commands that precede an invalid command in a multiple command program message is
executed.
4. Valid commands that follow an invalid command in a multiple command program message is
ignored.
Response messages
A response message is the message sent by the instrument to the computer in response to a query
command program message.
Sending a response message
After sending a query command, the response message is placed in the output queue. When the
Model 6517B is then addressed to talk, the response message is sent from the output queue to the
computer.
Multiple response messages
GPIB: If you send more than one query command in the same program message (see
Multiple
command messages
(on page 11-14)), the multiple response message for all the queries is sent to
the computer when the Model 6517B is addressed to talk. The responses are sent in the order that
the query commands were sent and are separated by semicolons (;). Items within the same query are
separated by commas (,). The following example shows the response message for a program
message that contains four single item query commands:
0; 1; 1; 0
RS-232 Interface: Instead of commas, a
<CR>
,
<LF>
separates each response from multiple queries
in the same program message.
Response Message Terminator (RMT)
Each response message is terminated with an
LF
(line feed) and
EOI
(end or identify). The following
example shows how a multiple response message is terminated:
0; 1; 1; 0 <RMT>
Message exchange protocol
The message exchange protocol can be summarized by the two following rules:
Rule 1. You must always tell the Model 6517B what to send to the computer.
The following two steps must always be performed, in this order, to send information from the
instrument to the computer:
1. Send the appropriate query commands in a program message.
2. Address the Model 6517B to talk.
Rule 2. The complete response message must be received by the computer before another program
message can be sent to the Model 6517B.
