B&K Precision 4034 - Manual - Manual (Page 38)

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4.5.1 The Input Buffer
The device has a 128-byte long cyclic input buffer. Decoding of remote messages begins as soon as the input
buffer is not empty, that is, as soon as the controller has sent at least one byte to the device. Should the input
buffer be filled up by the controller faster than the device can remove the bytes and decode them, the bus
handshake is not completed until room has been made for more bytes in the buffer. This prevents a fast controller
from overrunning the device with data.
If the user has sent part of a Program Message, but not the Program Message Terminator, and wishes to abort the
message decoding and execution, the Device Clear command may be sent, or front panel operation resumed (in
REMS only).
4.5.2 The Output Queue
The device has a 100-byte long output queue in which it stores response messages for the controller to read. If at
the time a response message is formatted the queue contains previously formatted response messages, such that
there are not enough places in the queue for the new message, the device will put off putting the message in the
queue until there is place for it.
The Status Byte MAV bit, when set, indicates that part or all of a response message is ready to be read.
4.5.3 Response Messages
The device sends a Response Message in response to a valid query. All queries return a single Response Message
Unit, and all query responses are generated at the time the query is parsed.
4.5.4 Coupled Commands
Coupled Commands are either commands whose execution validity depends on the value of other parameters, or
commands whose execution changes the value of another parameter. The execution of commands designated as
being coupled is deferred until all other commands in the same Program Message have been executed. The
coupled commands are then grouped together according to their functionality, and executed as a group. All
parameters of the pulse generator are coupled.
4.6 Instrument Identification
The *IDN? common query is used to read the instrument's identification string. The string returned is something
similar to the following:
B&K, MODEL 4034,0,V0.40
4.7 Instrument Reset
The *RST common command effects an instrument reset to the factory default power up state.