Monitoring System Operation

Monitoring System Operation

In this case, the bit or bits that satisfy the service-request condition remain in the true state until the status byte is interrogated by the system-level, serial-poll command SPOLL, or until the system-level CLEAR command is executed. These commands clear the status byte so that all the bits in the byte once again re￿ect the current state of the analyzer until another service request occurs. In this way, the process begins again.

Service-Request Mask The service-request mode is enabled and controlled by the request-service- condition command, RQS. It de￿nes a service-request mask which speci￿es which of the status-byte bits may generate a service request. Below, RQS speci￿es the ERROR-PRESENT and COMMAND-COMPLETE states (bits 5 and 4) for service requests.

Example Enable service requests for an ERROR-PRESENT condition.

OUTPUT 723;"RQS 48;" Selects bit 5 and 32 to enable service- request mode for ERROR-PRESENT.

Once RQS is executed, the analyzer requests service by setting the SRQ line true when any of the enabled conditions become true.

Optical Spectrum-Analyzer Status-Byte Register

Bit Number

Decimal Equivalent

Analyzer State

 

 

 

Description

 

 

 

 

 

 

 

7

128

 

Unused

 

 

 

6

64

RQS

Set

when

any

selected

service condition is met.

5

32

ERROR-PRESENT

Set

when

error

register

contains an error.

416 COMMAND-COMPLETE Set at completion of command execution.

3

8

 

Unused

 

 

 

 

 

2

4

END-OF-SWEEP

Set at completion of sweep .

 

 

 

1

2

MESSAGE

Set when

messages

appear, such as the

uncalibrated or

 

 

 

corrected

prompts,

\UNCAL"

or

\USERCAL."

0

 

TRIGGER-ARMED

Set when

analyzer

is ready

to

receive a

sweep trigger .

1

 

 

 

 

 

 

 

 

 

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