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Model 8902A
Operation
PROCEDURE
To cause the instrument to run through its internal checks and reset the instrument to its default
state. turn the instrument
o f f ,
then o n again.
To
reset the Measuring Receiver to its default state but bypass the internal power-up checks, select
INSTR PRESET (Blue Key, AUTOMATIC OPERATION), o r issue a device clear command from
a n HP-IB controller.
To initiate the internal power-up checks, select 40.0 SPCL.
HP-IB PROGRAM CODES
INSTR PRESET (Device Clear)
=
IP
SPCL
=
SP
T h e instrument can also be preset using the device clear bus command. (Refer to the Rcmoie section
o n page
3-?5.)
COMMENTS
Setting the Instrument to a Known State.
T h e Instrument Preset feature is a very simple means of setting the instrument to a known state
when writing test procedures involving the Measuring Receiver.
Losing Instrument States with a New Controller Assembly.
After plugging in a new controller Assembly, some or all of the instrument states stored through
power-down may be non-existent. If this information is lost:
a. T h e Recall function reverts to the Instrument Preset state.
b. T h e R F Power measurement will:
(1)
display Error 15, (2) light the UNCAL and RECAL
annunciators, and (3) use the default zero and calibration factors. (The R F power
calibration factors must be re-entered.)
c. T h e calibration factors for Tuned RF Level will be displayed as
O.Oo/o
(using Special
Function 38).
d. AM and FM calibration factors will be 100% when enabled (using Special Fiinction
16
o r
17).
Instrument Preset Clears Pending Require Service Messages.
When
the
instrument is preset, any pending Require Service Message is cleared.
(For
more details,
refer t o Receiving the Clear Message, in Remote Operation.)
CLEAR Key.
T h e HP-IB Clear message should not be confused with the front-panel CLEAR key o r its CL HP-
1B code. T h e HP-IS Clear message presets the instrument. The CLEAR key clears the display and
returns the instrument to its previous state.
Alternative to Turning the Instrument Off and then On.
Lse speciai fiinction 40.0 t o cause the Measuring Receiver t o pass through its internal checks. (Special
function 40.0 is not accessible from the HP-1B.)
3-24 I
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