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Chapter 8 Advanced Programming
GPIB (IEEE-488.2) Overview - Functional Elements
Functional Elements - Syntax and Nomenclature
In order to establish programming consistency among different manufacturers’ devices, IEEE-488.2 has
defined a set of rules governing message headers, mnemonics, separators, data types and terminators.
The following overview, which is very similar to the RS-232 counter part in the previous section, will
familiarize the programmer with the fundamentals of these rules. As seen below, the rules for command
and query messages are much more flexible than their precise response message counterparts.
<PROGRAM MESSAGE UNIT> - This is the basic message, and represents an operation to be per-
formed by the device. As an example, if you wanted to create a sinewave with 5 cycles in the currently
selected waveform, the appropriate <PROGRAM MESSAGE UNIT> would be:
WVFM:SINE 5,0
Notice that a colon (ASCII 3A) is used to separate the <program mnemonic> WVFM from SINE . For
query responses the similarly structured <RESPONSE MESSAGE UNIT> is used. A complete list of
<PROGRAM MESSAGE UNITS> and <RESPONSE MESSAGE UNITS> for the 2411B, with
definitions, mnemonics, and limitations is given in chapter 7.
General rules:
1. <program mnemonic> shall have maximum length of 12 characters.
2. “:” is used to separate <program mnemonics>, and when preceding a
<PROGRAM MESSAGE UNIT>, it indicates that the following <program mnemonic> is at
the root level.
<PROGRAM MESSAGE UNIT>
1. <program mnemonic> can be either upper or lower case alpha.
2. <white space> is only allowed at the end of the header, or next to a “,” or a “;”. (See note on
<white space> below.)
<RESPONSE MESSAGE UNIT>
1. <program mnemonic> shall contain upper case alpha only.
2. No <white space> allowed in message.
Note: <white space> is defined as a length of 1 or more of <white space characters>. A <white space
character> is a single ASCII byte in the range of 00-09, 0B-20 Hex.
<PROGRAM MESSAGE> - This is a series of <PROGRAM MESSAGE UNITS> sent to the device in
a single string. For example, to set the waveform to 1) a sinewave output with a zero degree starting
phase, 2) burst mode, 3) a burst of 5, and 4) an amplitude of 2.5V, you would send the following
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