ICS ELECTRONICS 4809A, Инструкция по эксплуатации

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A1.2 IEEE 488.2 STANDARD
A1.2.1 IEEE 488.2 Message Formats
The IEEE 488.2 Standard was established in 1987 to standardize message
protocols, status reporting and define a set of common commands for use
on the IEEE 488 bus. IEEE 488.2 devices are supposed to receive mes-
sages in a more flexible manner than they send. A message sent from GPIB
controller to GPIB device is called: PROGRAM MESSAGE. A message
sent from device to controller is called: RESPONSE MESSAGE. As part
of the protocol standardization the following rules were generated:
(;) Semicolons are used to separate messages.
(:) Colons are used to separate command words.
(,) Commas are used to separate data fields.
<nl> Line feed and/or EOI on last character terminates a
'program message'. Line feed (ASCII 10) and EOI
terminates a RESPONSE MESSAGE.
(*) Asterisk defines a 488.2 common command.
(?) Ends a query where a reply is expected.
A1.2.2 IEEE 488.2 Reporting Structure
With IEEE 488.2, status reporting was enhanced from the simple serial
poll response byte in IEEE 488.1 to the multiple register concept shown in
Figure A-3. The IEEE 488.2 Standard standardized the bit assignments in
the Status Byte Register, added eight more bits of information in the Event
Status Register and introduced the concept of summary bits reporting to
the Status Byte Register. The Status and Event registers have enabling
registers that can control the generation of their summary reporting bits and
ultimately SRQ generation. Each 488.2 device must implement a Status
Byte Register, a Standard Event Status Register and an Output Message
Queue as a minimum status reporting structure. A device may include
any number of additional condition registers, event registers and enabling
registers providing they follow the model shown in Figure A-3.
A1.2.3 IEEE 488.2 Common Commands
The IEEE 488.2 Standard also mandated a list of required and optional Com-
mon Commands that all 488.2 devices could support. All of the Common