Agilent Technologies EPM-P Series Programming Manual page 260

CALibration Subsystem
CALibration[1]|2:RCALibration <boolean>
Error Messages
When CAL[1]|2:RCAL is ON and the sensor currently connected to the
appropriate channel (A or B) has not been zeroed and calibrated, then any
SCPI command which would normally return a measurement result (for
example, FETC?, READ?, MEAS? etc) will not return a result but will
generate the error -230, "Data corrupt or stale; Please zero and Cal."
Once the sensor has been zeroed and calibrated the commands which
return measurement results will function normally.
EPM-P Series Power Meters Programming Guide 4-11
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