CALIBRATION
Calibration of the AP5103 is accomplished by the conventional shunt technique, using an internally
installed calibration resistor, or via the "dead-weight" method.
Calibration Resistor. If a fixed resistor is shunted across one arm of a strain gage bridge, it
produces an unbalance equivalent to that of a particular value of mechanical input. If this Equivalent
Input value is accurately known, it can be used as a reference point for shunt calibration of the
system. Upon completion of installation of the transducer and its associated cabling, the user can:
1.
Perform an overall dead weight calibration using a precisely known
value of mechanical input. The calibration can then be transferred to the
installed calibration resistor for convenience in subsequent checking.
2.
Replace the installed calibration resistor with one (or an equivalent
resistance value) supplied by the transducer manufacturer to achieve a
precisely known Equivalent Input allowing the instrument sensitivity to
be adjusted correctly.
3.
Determine the Equivalent Input value for the installed calibration resis-
tor, knowing the transducer sensitivity, and adjust the instrument sen-
sitivity accordingly.
A one percent, 59-kilohm calibration resistor is installed in the AP5103 at the factory. The installed
resistor can usually be used even though the transducer calibration data mentions some other
resistance value. In Section 4 of this manual, the techniques described above are demonstrated. If,
however, the installed value of calibration resistor is not appropriate for the transducer and
measurement range to be used, the 59-kilohm resistor should be replaced at this time. The
calibration resistor is mounted on terminals located internally to the AP5103 conditioner's printed-
circuit board. It can be accessed by removing the instrument case (Fig. 5).
Note: A variety of DC Load Cells and Slip Ring Torque Transducers are supplied
with the appropriate calibration resistor integral to the transducer. When this type
of transducer is used it will be necessary to place a short across the 59-kilohm
resistor internal to the instrument. The transducer calibration resistor can be appropri-
ately connected to the AP5103 calibration circuit via the transducer cabling. Refer to
cabling diragam section of this manual in the area of CAL SENSE.
This section contains the instructions for calibrating the AP5103. Included is a functional description
of the instrument front-panel (see Figure 2). To perform calibration, proceed as follows with the
sensor or calibration standard connected.
A.
Turn power ON to the AP5103 DC Power input terminal (11 to 28 Vdc input)
The front-panel indicator should light green to indicate the application of
dc power. Allow 10 minutes of warmup for stabilization of transducer
characteristics. Set the Coarse Zero and Span controls label marked position.
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