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Chapter 2
2-5
HP ESA Status Registers
Using the Analyzer Status Registers
3. Send GPIB commands to enable the bit that monitors the condition
and to enable the summary bits that report the condition to the RQS
bit.
4. Enable the controller to respond to service requests.
When the condition changes, the analyzer sets the RQS bit and the
GPIB SRQ line. The controller is informed of the change as soon as it
occurs. The time the controller would otherwise have used to monitor
the condition can now be used to perform other tasks. Your program
determines how the controller responds to the SRQ.
Generating a Service Request
To use the SRQ method, you must understand how service requests are
generated. Bit 6 of the status byte register is the request service (RQS)
bit. The RQS bit is set whenever something (that it has been configured
to report using
*SRE
) changes. It is cleared when the status byte
register is queried using
*SRE?
(with a serial poll.) It can be queried
without erasing the contents with
*STB?
.
When a register set causes a summary bit in the status byte to change
from 0 to 1, the analyzer can initiate the service request (SRQ) process.
However, the process is only initiated if both of the following conditions
are true:
• The corresponding bit of the service request enable register is also
set to 1.
• The analyzer does not have a service request pending. (A service
request is considered to be pending between the time the analyzer
SRQ process is initiated and the time the controller reads the status
byte register.)
The SRQ process sets the GPIB SRQ line true. It also sets the status
byte request service (RQS) bit to 1. Both actions are necessary to inform
the controller that the analyzer requires service. Setting the SRQ line,
only informs the controller that some device on the bus requires service.
Setting the RQS bit allows the controller to determine which analyzer
requires service.
If your program enables the controller to detect and respond to service
requests, it should instruct the controller to perform a serial poll when
the GPIB SRQ line is set true. Each device on the bus returns the
contents of its status byte register in response to this poll. The device
whose RQS bit is set to 1 is the device that requested service.
Содержание E4401B
Страница 6: ...vi ...
Страница 14: ...xiv Contents ...
Страница 64: ...2 34 Chapter2 HP ESA Status Registers Using the Analyzer Status Registers ...
Страница 65: ...3 1 3 Programming Examples ...
Страница 118: ...3 54 Chapter3 Programming Examples Entering Amplitude Correction Data Close the session viClose viESA viClose defaultRM ...
Страница 151: ...4 1 4 Programming Command Cross References ...
Страница 286: ...5 132 Chapter5 Language Reference UNIT Subsystem ...
Страница 287: ...6 1 6 HP 8590 HP ESA Spectrum Analyzers Programming Conversion Guide ...
Страница 292: ...1 HP 8590 HP ESA Spectrum Analyzers Conversion Guide ...
Страница 368: ...7 1 7 Error Messages ...
Страница 393: ...7 26 Chapter7 Error Messages 201 to 799 Device Specific Errors ...