Fluke PM6681 Notation Habit in Command Syntax, Syntax of Response Messages, Responses, Example

Introduction to SCPI

Notation Habit in Command Syntax

To clarify the difference between short and longform, the shortform in a syntax specification is shown in upper case let- ters and the remaining part of the longform in lower case letters.

;

< R e s p o n s M e s s a g e U n it >

Fig 3-9Syntax of a Terminated

Response Message.

Notice however, that this does not specify the use of upper and lower case charac- ters in the message that you actually sent. Upper and lower case letters, as used in syntax specifications, are only a notation convention to ease the distinction be- tween long and shortform.

￿Syntax of Response Messages

The response of a SCPI instrument to a query (response message unit) consists of one or more parameters (data elements) as the following syntax diagram shows. There is no header returned.

,

< P a r a m e t e

The response message terminator (rmt) is always NL^END, where:

NL^END is <new line> code (equal to <line feed> code = ASCII 10 decimal) sent concurrently with the END message. The END message is sent by asserting the EOI line of the GPIB bus.

Responses:

A SCPI instrument always sends its re- sponse data in shortform and in capitals.

Example:

You program an instrument with the fol- lowing command:

SEND→ :ROSCillator:SOURce￿EX-
r >	Ternal

Figure 3-8Syntax of a Response Message Unit.

If there are multiple queries in a program message, the instrument groups the multi- ple response message units together in one response message according to the following syntax:

Then you send the following query to the instrument:

SEND→ :ROSCillator:SOURce?

The instrument will return:

READ← EXT

response in shortform and in capitals.

Program and Response Messages 3-9