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an appropriate IEEE 488.1 command, or by cycling the device power.
4.3 Interface Function Subsets
The following interface function subsets are implemented in the MODEL 4076 and 4079:
SH1, AH1, T6, L4, SR1, RL1, PP0, DC1, DT1, E2, C0
4.4 Device Address
The GPIB address of the device may be set to any value from 0 to 31. The address may be changed from the front
panel, using the numeric keypad or the rotary encoder, or via the GPIB itself using the command:
:SYSTem:COMMunicate:GPIB:ADDRess
Setting the device to address 31 puts it in the 'off-bus' state. In this state it will not respond to messages on the
GPIB. If the device is in the REMS when set to address 31, an internal 'return-to-local' command will be given,
setting the device to the LOCS. If the device is in the RWLS, the 'return-to-local' command is ignored, and the
device remains in the RWLS. The only way to then re-establish communication with the device over the GPIB is
to cycle the power, and to then change the address to that required from the front panel.
4.5 Message Exchange Protocol
The device decodes messages using the Message Exchange Protocol (MEP) defined in IEEE 488.2. The following
functions implemented in the MEP must be considered:
4.5.1 The Input Buffer
The device has a 256-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 he 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
