User`s guide

9
4.10 Using the Agilent E-series power sensors
The E-series power sensors (E4412A and E4413A)
can only be used with EPM series power meters
and cannot be used with the 437B or 438A power
meters. However, the E-series sensors can be used
with the EPM series power meters in 437B and
438A language mode. Due to the fact that the
E-series sensors have calibration factors stored
in sensor EEPROM, the sensor calibration factor
and reference calibration factor commands are
no longer valid. Sending these commands will
cause a syntax error as detailed below.
• Status register bit 2 will be set (entry error)
• Status message entry error field will be set to 50
(calibration factor out of range/ignored)
• Status message entry error field will be set to 91
(invalid GPIB code)
It is possible to use an E-series sensor in place
of an 8480 series sensor. However, it is worth being
aware of the functional differences between the
two families, particularly regarding calibration
factors. Two common methods for holding 8480
series sensor calibration data are described below.
• In 437B language mode only, the sensor calibra-
tion data can be held within one of the power
meter’s sensor calibration tables. In this case the
data has previously been entered into a specific
table and the calibration table selected using the
SE command. Prior to making a measurement,
the frequency at which the measurement is being
made is sent to the power meter using the FR
command. The power meter interpolates the cal
factor from the sensor cal table. In applications
of this nature, the E-series sensor can be directly
substituted in place of the 8480 series sensor
as the calibration data held within the E-series
sensor EEPROM effectively becomes the selected
table. The SE command is now redundant and
will cause an entry error.
• The 8480 sensor calibration data can be held
on a host computer. Prior to making a measure-
ment, the frequency at which the measurement
is to be made is used by the host software to
derive the correct calibration factor. This cali-
bration factor is sent to the power meter using
the KB command. In this application, the host
software will require modifications if an 8480
sensor is to be replaced with an E-series sensor.
Provided no system corrections are included in
the calibration factor, then these modifications
should be straightforward. For example, send
the frequency to the power meter rather than
the calibration factor. If system corrections need
to be included, then the section on Frequency
Dependent Offsets (FDO) in the Agilent EPM
series power meter’s Programming Guide should
be referred to (for EPM series power meter
firmware revision 1.02 and 2.02 onwards).