How To Use Register; The Condition Polling Method - Keysight N1911A Programming Manual

1 Power Meter Remote Operation

How to Use Register

There are two methods to access the information in status groups:
– the polling method, or
– the service request (SRQ) method. (GPIB mode only)
Use the polling method when:
– your language/development environment does not support SRQ interrupts.
– you want to write a simple, single purpose program and do not want to add the
Use the SRQ method when you:
– need time critical notification of changes.
– are monitoring more than one device which supports SRQ interrupts.
– need to have the controller do something else while it is waiting.
– cannot afford the performance penalty inherent to polling.

The Condition Polling Method

In this polling method, the power meter has a passive role. It only informs the
controller that conditions have changed when the controller asks. When you
monitor a condition with the polling method, you must:
1 Determine which register contains the bit that monitors the condition.
2 Send the unique query that reads that register.
3 Examine the bit to see if the condition has changed.
The polling method works well if you do not need to know about the changes the
moment they occur. The SRQ method is more effective if you must know
immediately when a condition changes. Detecting an immediate change in a
condition using the polling method requires your program to continuously read
the registers at very short intervals. This is not particularly efficient and there is a
possibility that an event may be missed.
For example on measurement polling, refer to
76
complexity of setting an SRQ handler.
N1911A/1912A P-Series Power Meters Programming Guide
Figure B-B-1 on page B-2.