Troubleshooting Calibration Adjustments - ABB AV1 Operating Instructions Manual

CALIBRATION

TROUBLESHOOTING CALIBRATION ADJUSTMENTS

Tools Required:
CAUTION
TROUBLESHOOTING CALIBRATION ADJUSTMENTS
4 - 8
The I/P converter of the Type AV2 positioner comes from the fac-
tory completely calibrated. Use the following procedures only
when operating difficulties occur. The corrective action column
of Table 6-1 indicates when to use the troubleshooting calibration.
The purpose of this procedure is to adjust the I/P converter so that
a four to 20-milliamp input signal will produce a 20.7 to 103.4-kilo-
pascal (3.0 to 15.0-pounds per square inch gage) signal. Use the
following procedure to adjust the I/P converter. The supply air
must be connected to the positioner for this procedure.
Digital voltmeter.
•
Calibrated 0 to 30-psig instrument gage.
•
Small screwdriver.
•
Current source.
•
Do not exceed the maximum supply pressure of 1034 kilo-
pascals (150 pounds per square inch gage). Exceeding this
pressure could cause equipment damage.
1. Connect the calibrated zero to 30-psig instrument gage or
other accurate pressure measuring device to the I port to monitor
the signal pressure during calibration.
2. Turn on the supply air to the positioner.
3. Provide a four-mA signal to the I/P converter and observe the
output pressure. If the pressure equals 20.7 kPa (3.0 psig) go to
Step 5. If the pressure does not equal 20.7 kPa (3.0 psig) go to
Step 4.
4. Adjust the zero screw (→0←) on the bottom of the I/P con-
verter (Fig. 4-7) until the output pressure equals 20.7 kPa (3.0
psig). Clockwise rotation increases pressure.
5. Apply a 20-mA signal to the I/P converter and observe the out-
put pressure. If the pressure equals 103.4 kPa (15.0 psig) go to
Step 7. If the pressure does not equal 103.4 kPa (15.0 psig) go to
Step 6.
6. Adjust the span screw (⏐↔⏐ ) on the bottom of the I/P con-
verter (Fig. 4-7) until the output pressure equals 103.4 kPa (15.0
psig). Clockwise rotation increases pressure.
7. Repeat Steps 3 through 6 until the 20.7 kPa (3.0 psig) and
103.4 kPa (15.0 psig) outputs are attained with four and 20-mA
signal inputs.