3-7
IM 701310-17E
Overview of the GP-IB Interface
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App
Index
Multi-Line Messages
Eight data lines are used to transmit multi-line messages. The messages are classified
as follows:
•
Address Commands
These commands are valid when the instrument is designated as a listener or as a
talker. The following five types are available.
Commands that are valid on an instrument that is designated as a listener
• GTL (Go To Local)
• SDC (Selected Device Clear)
• PPC (Parallel Poll Configure)
• GET (Group Execute Trigger)
Commands that are valid on an instrument that is designated as a talker
• TCT (Take Control)
•
Universal commands
These commands are valid on all instruments regardless of the listener and talker
designations. The following five types are available.
• LLO (Local Lockout)
• DCL (Device Clear)
• PPU (Parallel Poll Unconfigure)
• SPE (Serial Poll Enable)
• SPD (Serial Poll Disable)
In addition, listener address, talker address, and secondary commands are also
considered interface messags.
Interface messages
Uni-line
messages
Address
commands
Universal
commands
*IFC
*REN
*GTL
*SDC
*LLO
*DCL
*SPE
*SPD
Listener
address
Talker
address
Secondary
commands
Multi-line messages
PPC
GET
TCT
IDY
PPU
Interface messages that DL9000 supports are indicated with
∗
marks.
Note
The Differences between SDC and DCL
In multi-line messages, SDC messages are those that require talker or listener designation and
DCL messages are those that do not require the designation. Therefore, SDC messages are
directed at a particular instrument while DCL messages are directed at all instruments on the
bus.
3.6 Responses to Interface Messages
