WA-1100/WA-1600 Wavemeter Operating Manual
3 Remote Communications
08115-M-00 Rev E
3-9
instrument Status Byte
Bit
Bit Value
Condition
5
32
a bit is set in the questionable register (see STATus
subsystem)
3
8
errors are in the error queue (see SYSTem subsystem)
2
4
a bit is set in the event status register
Measurement Instructions
Use the measurement instructions to return a reading to the computer. The four basic
measurement instructions are CONFigure, FETCh, READ, and MEASure. Functions for
these instructions are POWer, ENVironment, WAVelength, WNUMber, and
FREQuency.
A :FETCh will return a reading based on the last complete scan. Using :FETCh, it is
possible to get new measurements at the instrument's scan rate of up to 10 per second on
a WA-1100 and up to 1 per second on a WA-1600. However, if :FETCh queries are
made faster than the instrument's scan rate, it is possible to get the same reading twice.
Old readings are indicated by a bit in the questionable status register.
:MEASure and :READ get a new reading after the next complete scan. :MEASure and
:READ guarantee that each reading returned is a new one. However, because :MEASure
and :READ wait until after the next complete scan before returning a reading,
measurement rates will be about half the instrument's scan rate. If you want to get
multiple measurement types from a single scan (i.e. WAVelength, POWer, etc.), you
should use :READ followed by one or more :FETCh queries.
:MEASure and :READ are actually macros that execute multiple SCPI commands.
:READ is equivalent to:
:ABORt
:INITiate
:FETCh[:<function>]?
and :MEASure is equivalent to:
:ABORt
:CONFigure <function>
:READ?
For the instrument, :MEASure and :READ perform essentially the same function.
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