Initial Adjustments; On Stack Zero And Span Calibration - Emerson OPM 3000 Instruction Manual

OPM 3000

INITIAL ADJUSTMENTS

On Stack Zero and Span
Calibration
3-4
The following equipment adjustments must be made prior to operation of the
OPM 3000.
NOTE
The instrument has been calibrated at the factory to specifications received
from the customer. When the flange to flange dimensions are exactly as cited,
the initial adjustments required are minimal.
NOTE
For detailed information on using the zero jig, refer to Section 5: Zero Jig and
Neutral Density Filter.
Before adjusting the OPM 3000 verify the following conditions:
• The boiler or process is shut down and a clear stack condition exists
(if not, use the optional OPM 3000 test flange kit.)
• Power is disconnected whenever removing or replacing the transceiver
housing.
• The transceiver and retro reflector lenses are clean.
• The beam alignment procedure has been completed.
Use the following steps to perform the zero and span calibrations.
Proceed only with a clear stack condition.
1. Remove the transceiver cover by removing the screw below the target
viewing window and pulling the housing straight back until it clears the
optical plate.
2. Connect a multimeter to measure the 4-20 mA signal from the
transceiver to the control unit. Use terminals 8 (+) and 9 (-) on the
transceiver terminal board (TB) (Figure 2-9). Connect the multimeter in
series with the signal wiring or remove both signal wires and place the
mutimeter across terminals 8 (+) and 9 (-).
NOTE
Allow opacity readings to stabilize before proceeding to the next step. Wait
one minute for maximum accuracy.
3. Adjust PT-1 (zero) (Figure 3-3) on the R/M signal processor board
slowly clockwise several turns until the 4-20 mA signal decreases to
10 mA.
4. Slowly turn the PT-1 (zero) counterclockwise until the 4-20 mA signal
increases to 20 mA (zero % opacity).
Instruction Manual
IM-105-3000, Rev 2.0
November 2008