CALIBRATE DEVICE: HPRT
0 ADJ: 0.0
10 ADJ: 0.0
CAL DATE: 05-21-96
SER NUM: A38123
For the 2561 HTPRT module the list of parameters includes
0_ADJ
and
10_ADJ
as described above. The list also includes the calibration date (CAL
DATE) parameter, used to record the date the module was calibrated, and the
SER NUM parameter, used to record the serial number of the module.
8.4.3
Calibration Procedure
Calibration requires adjustment of the
0_ADJ
, and
10_ADJ
parameters at two
specific input resistances. If the resistances used are approximately 0
Ω
and
10
Ω
respectively the adjustments are independent and the procedure is simple.
Either channel can be used for calibration. Set the conversion type to R(
Ω
) to
display resistance (see Section 5.2.1.1 ). The accuracy required of the resis-
tance standards is 1/4 of the instrument accuracy: that is ±0.000025
Ω
at 0
Ω
and
±0.00012
Ω
(12 ppm) at 10
Ω
. The recommended procedure is as follows:
1.
Connect a 0
Ω
resistor to the input and measure its resistance. If a short-
ing wire is used, the wire should run from the inside black terminal to
the inside red terminal to the outside red terminal then back across to the
outside black terminal. Note the average error in the measurement. Ad-
just the 0_ADJ parameter by subtracting the measured error. For exam-
ple, if the input is exactly 0.0
Ω
and readout shows –0.211m
Ω
, 0_ADJ
should be adjusted by adding 0.000211 to it.
2.
Connect a 10
Ω
resistor (12 ppm accuracy) to the input and measure its
resistance. Note the average error in the measurement. Adjust the
10_ADJ
parameter by subtracting the measured error. For example, if the
input is exactly 10.0
Ω
and the readout shows 10.02955
Ω
,
10_ADJ
should be adjusted by subtracting 0.02955 from it.
3.
Record the date with the calibration date parameter.
4.
Verify the accuracy at 0
Ω
, 1
Ω
or 25
Ω
, 10
Ω
, and 25
Ω
. Verify the accu-
racy of both channels with selected resistances. The accuracy must be
within the short-term accuracy given in the specifications.
123
8 2561 HTPRT Module
Calibration
