User manual

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 2000 Multimeter is then addressed to talk, the response message is sent
from the Output Queue to the computer.
Multiple response messages
If you send more than one query command in the same program message (see the para-
graph entitled, “Multiple Command Messages”), the multiple response messages for all the
queries is sent to the computer when the Model 2000 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 com
-
mands:
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 Model 2000 what to send to the computer.
The following two steps must always be performed to send information from the instru-
ment other computer:
1. Send the appropriate query command(s) in a program message.
2. Address the Model 2000 to talk.
Rule 2. The complete response message must be received by the computer before an-
other program message can be sent to the Model 2000.
2000-900 (J - Aug 2010) BOOK.fm Page 38 Wednesday, October 12, 2011 12:29 PM