R3132 Series Spectrum Analyzer Operation Manual
4.2.4 Responses to Interface Messages
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4.2.4
Responses to Interface Messages
The IEEE Standard 488.1-1978 defines how the spectrum analyzer responds to interface messages. The
responses are described in this section.
For information on how to send interface messages to the spectrum analyzer, refer to the instruction man-
ual of the controller you are using.
(1)
Interface Clear (IFC)
The IFC message is transmitted directly to the spectrum analyzer through a signal line. The message
allows the spectrum analyzer to stop the operation of the GPIB bus. Although all input/output oper-
ation is stopped, the input/output buffer is not cleared. Note that the DCL is used to clear the buffer.
(2)
Remote Enable (REN)
The REN message is transmitted directly to the spectrum analyzer through a signal line. If the spec-
trum analyzer is specified as a listener when the message is true, the spectrum analyzer is in remote
mode. The spectrum analyzer remains in remote mode until the GTL message is received, REN
becomes false, or you press the LOCAL key.
When the spectrum analyzer is in local mode, it ignores all received data, and key inputs (except for
LOCAL key input) and when the spectrum analyzer is in LOCAL LOCKOUT mode, it ignores all
key input.
(3)
Serial Polling Enable (SPE)
When the spectrum analyzer is receiving a message from an external device, it is in serial polling
mode. If the spectrum analyzer is specified as a talker in this mode, it sends status bytes instead of
normal messages. The spectrum analyzer remains in the serial polling mode until the SPD (Serial
Polling Disable) message or the IFC message is received.
When the spectrum analyzer sends an SRQ (Service Request) message to the controller, bit 6 (RQS
bit) of the response data is set to 1 (true). When the spectrum analyzer has finished sending this mes-
sage, the RQS bit reverts to 0 (false). The SRQ message is sent directly through a signal line.
(4)
Device Clear (DCL)
When the spectrum analyzer receives a DCL message, it performs the following actions:
•
Clears the input and output buffers.
•
Resets syntax analysis, execution control, and response data generation.
•
Cancels all commands that prevent the remote command from being executed next.
•
Cancels commands that are paused to wait for other parameters.
When the spectrum analyzer receives the DCL message, it does not do the following:
•
Changes data set or stored in the spectrum analyzer.
•
Interrupt front panel operation.
•
Modify or interrupt any spectrum analyzer operations being executed.
•
Change any status bytes other than MAV (MAV becomes 0 when the output buffer is cleared).