5-8
Relative, mX+b, m/X+b, and log
Model 6487 Reference Manual
C) :DATA? and :DATA:LATest?
The INITiate command must be sent to trigger the measurements and calculations. The
number of calculations depend on how many measurements the instrument is programmed
to perform.
If the instrument is programmed to perform a finite number of measurements, the :DATA?
command will return all the CALC1 readings after the last reading is taken. The
:DATA:LATest? command will only return the last (latest) CALC1 reading.
If the instrument is programmed to perform an infinite number of measurements (arm
count or trigger count set to infinite), you cannot use the :DATA? command to return
CALC1 readings. However, you can use the :DATA:LATest? command to return the last
CALC1 reading after aborting the measurement process. After sending the INITiate com-
mand to start the measurement process, use the ABORt command to abort the measure-
ment process, then use :DATA:LATest? to return the last CALC1 reading.
Programming example — mX+b
This command sequence performs a single mX+b calculation, using “X” as the units des-
ignator, and displays the result on the computer CRT:
*RST
'Restore RST defaults.
CALC:FORM MXB
'Select mX+b calculation.
CALC:KMAT:MMF 2e-3
'Set scale factor (M) to 2e-3.
CALC:KMAT:MBF 5e-4
'Set offset (B) to 5e-4.
CALC:KMAT:MUN ‘X’
'Select X as units.
CALC:STAT ON
'Enable calculation.
SYST:ZCH OFF
'Disable zero check.
INIT
'Perform one measurement and
'calculate mX+b.
CALC:DATA?
'Request mX+b result.
