Rosemount P300, Installation And Operation Manual

Page: 41 / 48

A-5
Appendix A: Calibration
Electrical Calibration Test
Procedure To check the Model P300 validator’s electrical calibration:
Voltmeter 1. Turn on the validator.
2. Connect the validator test leads between the common (black) and
V (red) test sockets. Connect the leads to a stable voltage source.
3. Connect the test equipment voltmeter across the voltage source
(parallel to the validator).
4. Set the voltage source to zero. Record the voltages read on the
validator and the test validator. If the test validator shows zero
and the validator indicates a small offset, zero the validator by
holding down the
V
key while pressing the
ZERO
key.
5. Apply test voltages of 0 V, 12.5 V, 25 V, and 50 V, as measured on
the test equipment. Record the corresponding validator voltage
reading for each applied voltage.
6. Calculate the percentage error of the calibrator’s voltage reading
against the applied test voltage.
7. Verify that the calculated values are within the accuracy limits
stated in Pressure Specification and Ranges. on page 5-1.
Current
1. Turn on the validator.
2. Connect the validator test leads between the common (black) and
I (red) test sockets. Connect the validator in series with a test
milliammeter to a variable current source.
3. Set the current source to zero. Record the current reading on the
validator and the test validator. If the test validator shows zero
and the validator indicates a small offset current, zero the
validator by holding down the
I
key while pressing the
ZERO
key.
4. Apply test currents of zero, 20 mA, 40 mA, and 55 mA, as
measured on the test equipment. Record the corresponding
validator current reading for each applied current.
5. Calculate the percentage error of the validator’s current reading
against the applied test current.
6. Verify that the calculated values are within the accuracy limits
stated in Electrical Specifications on page 5-1.
Electrical Calibration
Adjustment Procedure The electrical calibration routines require the entry of two signals for
both the voltage- and the current-measuring circuits. Calibration data
for each measurement channel are not overwritten until both
calibration parameters have been entered and accepted.
To abort a calibration run without updating the existing calibration
data, turn the validator off before completion of the calibration
procedure. Alternatively, complete the calibration procedure and reply
NO
to the
ACCEPT CAL
? prompt given at the end of the procedure.
Calibrating Current Range To perform calibration of the current measurement channel:
1. Connect the validator test leads to the common (black) and the V
(red) test sockets. Connect the validator terminals parallel to a
calibrated digital voltmeter, preferably of greater accuracy than
the validator.
2. Enter the
VOLTAGE CALIBRATION
menu by pressing and holding the
V
key while turning the validator on. The validator now briefly
indicates
VOLTAGE CAL
before prompting for a password to allow
entry into the voltage calibration routine:
ENTER PIN
: 000
.
3. Enter a valid calibration PIN (Setting the PIN on page 3-3).
See Safety Messages on page A-1 for complete warning information.