Manual

HAPTER

Overview

WM-RCM-E Rev D ISSUED: February 2005

Whenever you expect a response from the oscilloscope, you must have the control program instruct the GPIB

or LAN interface to read from the oscilloscope. If the controller sends another program message without

reading the response to the previous one, the response message in the output buffer of the oscilloscope will be

discarded. The oscilloscope keeps to stricter rules for response messages than for acceptance of program

messages. While you can send program messages from the controller in uppercase or lowercase characters,

response messages are always returned in uppercase. Program messages may contain extraneous spaces or tabs

(white space), but response messages will not. And while program messages may contain a mixture of short and

long command or query headers, response messages always use short headers by default.

However, you can use the command COMM_HEADER to force the oscilloscope to use long headers, or none

at all. If the response header is omitted, the response transfer time will be minimized. But the response will not

be able to be sent back to the oscilloscope. Suffix units are also suppressed in the response. An advantage of

headerless operation is the ease with which programs can use the data, because they do not have to find and

remove the headers. But C1:PAVA? ALL will return a string like this - AMPL,292.3E-3,OK,DLY,-2.333E-

6,OK,FALL,95.121E-9,OK,MEAN,66E-6,OK,PER,332.8E-9,OK,PKPK,308E-3,OK,RISE,92.346E-

9,OK,RMS,106.1E-3,OK,SDEV,106.1E-3,OK,WID,166.3E-9,OK, even with CHDR OFF, because only the

header is removed. All other alphabetic information is always transmitted.

If you were to set the trigger slope of Channel 1 to negative, the query C1:TRSL? might yield the following

responses:

C1:TRIG_SLOPE NEG header format: long

C1:TRSL NEG header format: short

NEG header format: off

: Waveforms you obtain from the

oscilloscope using the query WAVEFORM?

are a special kind of response message.

Control their exact format by using the

COMM_FORMAT and COMM_ORDER

commands.

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