Error Messages; Status Reporting - ILX Lightwave OMM-6810B User Manual

Error Messages

Error messages may appear on either display. These errors are also held for
retrieval via GPIB. The error queue can be read by issuing the "ERR?" command.
This command returns a string containing up to ten error messages from the error
message queue.
If "ERR?" is sent when the error queue is empty an ASCII zero (0) is returned. If
the error queue is active bit #7 in the Status Byte is also set to one (1).
Appendix A contains an explanation of the error messages which may be reported
remotely by the 6810B.

Status Reporting

The status of the OMM-6810B is held within four internal registers. Figure 3.12
illustrates the structure of each register. Each is now described.
Condition:The Condition Register monitors the state of the device. For example, if
the input power is overloading the Measurement Head, bit #0 in the Condition
Register is set. Refer the COND? query in Chapter 4.
Event:The Event Register watches for changes in the device condition. For
example, if the input source is unstable, bit #4 in the Event Register is set. Refer
the EVENT? query in Chapter 4.
Standard Event:The Standard Event Register is defined by the IEEE-488.2
standard and is responsible for monitoring GPIB events such as Operation
Complete and Command Errors. Refer the *ESR? query.
Status Byte:The Status Byte is also defined by the IEEE-488.2 standard. The
status byte contains the summary of the other registers as well as reporting if the
error and message available queues are active. Refer the *STB? query.
Each register has an ENABLE register associated with it. The enable register
works like a mask or filter when updating that register's summary to the Status
Byte. For example, the Condition Register is filtered (logically ANDed) with the
Condition ENABLE Register. If the result is non-zero then Bit #1 in the Status
Byte is set to one. The Enable registers are set via unique GPIB commands.
Figure 3.12 illustrates the status reporting scheme of the 6810B. Each of the
registers may be accessed by a command or query. These commands are shown
near each register diagram in Figure 3.12.
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G P I B / I E E E 4 8 8 . 2 R E M O T E O P E R A T I O N
C H A P T E R
Error Messages
OMM-6810B
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