Boonton 4530 Peak Power Meter User Manual - Manual (Page 135)

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Boonton Electronics Chapter 4
4530 Series RF Power Meter Remote Operation
4.6 REMOTE SENSOR CALIBRATION
4.6.1 AutoCal (Peak or CW Sensors) - When maximum accuracy is required, an automatic sensor calibration
(AutoCal) should be used. This steps the sensor through a series of calibrated power levels and builds the sensor’s
linearity calibration table for its entire dynamic range. AutoCal is performed using the internal 50 MHz step calibrator
or the optional external 1 GHz step calibrator. The calibration process requires up to 2 minutes to accomplish with CW
and wider dynamic range peak sensors. The simplest way to accomplish this is to program a delay of approximately 2
minutes before reading the result flag from the 4530.
CAL2:INT:AUTOCAL? Calibrate the sensor connected to the SENSOR 2 input using the
internal 50 MHz step calibrator and return a “0” if the calibration
has completed success fully or a “1” if it has not.
{ WAIT 2 MINUTES } Allow sufficient time for the longest anticipated calibration.
{ READ flag } Read the result flag and proceed accordingly.
This method is simple but has a disadvantage. You must anticipate the time required. An incorrect estimate will waste
time or cause an error. A better but more complicated method makes use of the service request capability of the GPIB:
*CLS Clear all status registers.
*ESE 1 Enable the operation complete flag in the Event Status Register.
*SRE 32 Enable the Event Status Register to initiate a request for service
by setting the SRQ line of the GPIB true.
CAL2:INT:AUTOCAL?; *OPC Calibrate the peak sensor connected to the SENSOR 2 input
using the internal 50 MHz step calibrator and return a “0” if the
calibration has completed successfully or a “1” if it has not.
Begin an operation complete sequence.
{ WAIT FOR SRQ } Wait for an SRQ from the power meter over the GPIB bus.
{ SPOLL status byte } Perform Serial Poll sequence to read the instrument’s status byte
and clear the SRQ condition.
{ READ flag } Read the result flag and proceed accordingly.
If other STB or ESR bits are enabled, or if other instruments on the bus are able to set an SRQ, it may be necessary to
further examine the source of the SRQ to be certain that the completion of the calibration procedure is the cause.
4.6.2 Zero and FixedCal (CW Sensors only) - Where maximum accuracy is not necessary, most CW sensors
can be quickly calibrated by zeroing the sensor followed by a single-point FixedCal. Calibration and zeroing is
accomplished using the internal 50 MHz step calibrator or the optional external 1 GHz step calibrator. The zeroing
process requires up to 2 minutes to accomplish and the calibration process takes a few seconds. The simplest way to
accomplish this is to program a delay reading the result flag from the 4530.
CAL1:INT:ZERO? Zero the CW sensor connected to the SENSOR 1 input using
the internal 50 MHz step calibrator and return a “0” if zeroing
has completed successfully or a “1” if it has not.
{ WAIT 2 MINUTES } Allow sufficient time for the longest anticipated calibration.
{ READ flag } Read the result flag and proceed accordingly.
CAL1:INT:FIXED? Calibrate the CW sensor connected to the SENSOR 1 input at a
fixed level using the internal 50 MHz step calibrator and return a
“0” if the calibration has completed successfully or a “1” if it has
not.
{ WAIT 5 SECONDS } Allow sufficient time for the longest anticipated calibration.
{ READ flag } Read the result flag and proceed accordingly.