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How to use the Status Registers
N9340B Programmer's Guide
A program often needs to detect and manage error
conditions or changes in instrument status. The polling
method for you to programmatically access the information
in status registers.
In the polling method, the instrument has a passive role. It
only tells the controller that conditions have changed when
the controller asks the right question. In the SRQ method,
the instrument takes a more active role. It tells the
controller when there has been a condition change without
the controller asking. Either method allows you to monitor
one or more conditions.
The polling method works well if you do not need to know
about changes the moment they occur. To detect a change
using the polling method, the program must repeatedly read
the registers.
To monitor a condition:
— Determine which register contains the bit that reports the
condition.
— Send the unique SCPI query that reads that register.
— Examine the bit to see if the condition has changed.
You can monitor conditions in different ways.
• Check the instrument hardware and firmware status.
Do this by querying the condition registers which
continuously monitor status. These registers represent the
current state of the instrument. Bits in a condition register
are updated in real time. When the condition monitored by a
particular bit becomes true, the bit is set to 1. When the
condition becomes false, the bit is reset to 0.
• Monitor a particular condition (bit).
You can enable a particular bit(s), using the event enable
register. The instrument will then monitor that particular
condition(s). If the bit becomes true (0 to 1 transition) in
the event register, it will stay set until the event register is
cleared. Querying the event register allows you to detect that
Status Registers
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