KNOWLEDGEBASE
Item #: 1248 |
Created: 4/1/2013
Categories: Power Meter - WT200, Power Meter - WT2030/1030/2533
How do I Retrieve Data From the Instrument Only When it is Updated Using Pre-IEEE488.2 Commands?
Solution:
You can determine whether data was updated by performing a serial poll and referencing the status byte.
Bit 0 of the status byte (D101) changes to 1 when data is updated. When bit 0 changes to 1, bit 6 (D107) also changes to 1.
Also, bit 0 and 6 are reset when a serial poll is performed.
You can judge the data update status by referencing bit 0 and bit 6.
However, even if you suddenly read the status byte and determine that bit 0 and bit 6 are set to 1, this does not indicate at what time the update occurred. Therefore, perform a dummy serial poll, and clear the contents of the extended event register. Then perform repeated serial polls, and confirm the changing of the returned value's bit 0 and bit 6 to 1. Then if you send the "OD" command, the data is not read out until updated.
For details on the status byte, see the following:
Bit 0 of the status byte (D101) changes to 1 when data is updated. When bit 0 changes to 1, bit 6 (D107) also changes to 1.
Also, bit 0 and 6 are reset when a serial poll is performed.
You can judge the data update status by referencing bit 0 and bit 6.
However, even if you suddenly read the status byte and determine that bit 0 and bit 6 are set to 1, this does not indicate at what time the update occurred. Therefore, perform a dummy serial poll, and clear the contents of the extended event register. Then perform repeated serial polls, and confirm the changing of the returned value's bit 0 and bit 6 to 1. Then if you send the "OD" command, the data is not read out until updated.
For details on the status byte, see the following:
- WT1010 Digital Power Meter User's Manual
Page App1-13 - WT1030/1030M Digital Power Meter User's Manual
Page App1-15 - WT2010 Digital Power Meter User's Manual
Page App1-17 - WT2030 Digital Power Meter User's Manual
Page App1-17 - WT110E/WT130 Digital Power Meter User's Manual
Page 11-3 - WT200 Digital Power Meter User's Manual
Page 10-4 - WT210/230M Digital Power Meter User's Manual
Page 10-4
