Agilent Technologies 4288A, Руководство по программированию

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Appendix C 249
Status Reporting System
General Status Register Model
C
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Event register
The event register reflects the corresponding condition of the 4288A (e.g., occurrence of an
event) as a bit status. These bits continuously monitor changes in the 4288A’s state and
change the bit status when the condition (e.g., change bit status to “1” if a specific event
occurs) for each bit is met. You cannot change the bit status by issuing a GPIB command.
The Agilent 4288A has the following event registers:
• Standard Event Status Register (see Table C-2 for details.)
• Operation Status Event Register (see Table C-3 for details.)
Enable register
Setting the enable register allows you to specify event register bits that can set “1” to the
summary bit of the status byte register when an event occurs. The register bits work as
mask bits; setting “1” to an enable register will enable a corresponding bit in the event
register.
For example, when you want to set “1” as the summary bit in the status byte register by a
specific register condition, set the corresponding enable register to “1.”
Status byte register
If the enabled event register is set to “1,” a corresponding bit of the status byte register is
also set to “1.” This register also indicates the output queue and SRQ status.
The value of the status byte register can be read by using the
*STB?
command on
page 128 or the serial poll (SPOLL statement in HTBasic) from the controller. The
*STB?
command sets the analyzer to remote mode. On the other hand, the SPOLL statement in
HTBasic reads the status byte register value directly without the instrument being set to
remote. Therefore, you can continue to operate the front panel keys while a controller is
reading the status byte register.
Reading the status byte register by using the
*STB?
command does not affect the contents
of the status byte register. However, reading it with the SPOLL statement of HTBasic will
clear the RQS bit in the status byte register.
Setting the service request enable register using the
*SRE
command on page 127 can
generate a service request synchronously with the status byte register.