DH Instruments MOLBOX ANALOG CIRCUIT, User Manual

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MFC SWITCHBOX USER’S MANUAL
© 1997-2002 DH Instruments, Inc. Page 4
2.3 RECALIBRATE
A recalibration determines new calibration coefficients for the set, measure and sense lines based on the
supplied multimeter readings. To perform a recalibration, choose either a Voltage or Current mode
Recalibration from the Test Menu (see Section 3.6). The software will set 5 and 0.5 V or 20 and 5 mA
depending on the type of calibration selected. After each set point the multimeter readings must be
entered when prompted in the same manner as a calibration check, except it will do it twice. The first
time the software will calculate new adders and multipliers and write them to molbox1. The second time,
the software is attempting to verify that the new calibration was successful. Therefore, the second set of
data input by the user should be within the molbox specification. Once the calibration passes, the save
calibration option displays (see Section 3.1). If for some reason the calibration fails, the original
calibration values are restored.
While the calibration is running it is not necessary to do anything except wait for the software to inform
you when to input information or if there is a problem. To stop any calibration early just press ESC. If
early, the original calibration values are written back to the molbox.
There is a file named (molbox serial number (+_mA)).cfg that resides in the installation directory of the
Analog program. The file name will have ‘_mA’ after the serial number for current (mA) configuration files
only. In this file the current, previous, former and initial molbox calibration values and their dates are
maintained. In this case former refers to the value prior to previous.
Data for this file is used to restore previous calibration values in order to maintain metrological continuity
(see Section 3.6). At the beginning and end of each calibration, the molbox calibration values are
compared to the file data. If they do not match the file is updated. See Section 5.4 for an example .cfg file.