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S:\agilent\8920\8920b\PRGGUIDE\BOOK\CHAPTERS\usehpib.fb
Chapter 1, Using GPIB
Getting Started
•Guideline #3. Avoid program hangs.
If the program stops or “hangs up” when trying to ENTER a measured value, it is most
likely that the desired measurement field is not available. There are several reasons
that can happen:
1. The screen where the measurement field is located has not been DISPlayed before
querying the measurement field.
2. The measurement is not turned ON.
3. The squelch control is set too high. If a measurement is turned ON but is not
available due to the Squelch setting, the measurement field contains four dashes
(- - - -). This is a valid state. The Test Set is waiting for a signal of sufficient strength
to unsquelch the receiver before making a measurement. If a measurement field
which is squelched is queried the Test Set will wait indefinitely for the receiver to
unsquelch and return a measured value.
4. The RF Analyzer’s Input Port is set to ANT (antenna) while trying to read TX
power. TX power is not measurable with the Input Port set to ANT. The TX power
measurement field will display four dashes (- - - -) indicating the measurement is
unavailable.
5. The input signal to the Test Set is very unstable causing the Test Set to continuously
autorange. This condition will be apparent if an attempt is made to make the
measurement manually.
6. Trigger mode has been set to single trigger (TRIG:MODE:RETRig SINGle) and a
new measurement cycle has not been triggered before attempting to read the
measured value.
7. The program is attempting to make an FM deviation or AM depth measurement
while in the RX TEST screen. FM or AM measurements are not available in the RX
TEST screen. FM or AM measurements are made from the AF Analyzer screen by
setting the AF Anl In field to FM or AM Demod.