Land 4500 MKII Premier, Operation And Maintenance Manual

Page: 67 / 139

Model 4500 Premier Dust and Opacity Monitor
67
B3-3 Re-calibration
It is recommended that every three years a genuine clear stack calibration of the instrument is performed.
The Re-calibration command is used in performing this operation. Re-calibration is also required if a
calibration audit shows the instrument to be outside of acceptable limits. Please ensure that all optical
surfaces are clean and the optical path is not obstructed before performing any calibration. Re-calibration
must be carried out by a Land Service Engineer or other competent person. If the flange to flange path
length is altered (i.e. due to relocation of the instrument) contact Land customer services for instrument
pathlength setup advice.
Re-calibration should be carried out under clear stack conditions or in a
laboratory with the Transceiver set to the correct flange-to-flange path length .
1. Press and hold the Maintenance key for 3 seconds until the red LED illuminates.
2. Enter the password using the
↑
and
↓
keys, then press the ‘ENTER’ (
↵
) key. The default password
is 10.
3. Select the Calibration: menu with the
↑
or
↓
keys from the main menu.
4. Press the 'ENTER' (
↵ ↵↵
↵↵
) key. Scroll with the
↑
or
↓
keys until 'Re-calibrate' is displayed.
5. Press the 'ENTER' (
↵ ↵↵ ↵↵
) key. The display will show 'Clear path'. Ensure the measuring path
between the Transceiver and Retro-Reflector is clear of any obstruction.
6. When the measurement path is clear press the 'ENTER' (
↵ ↵↵
↵↵
) key again. The display will show
'Settling' while the clear path measurement is in progress, when complete the display will show
'100% point'.
7. Block the beam (
if the instrument is mounted on the stack, then the simplest method for
blocking the beam is to undo the two quick release clamps on the Transceiver and swing the
unit open).
8. Press the 'ENTER' (
↵ ↵↵ ↵↵
) key when ready. The instrument will automatically continue and calculate
the zero and span calibration check points. The display will indicate the progress of the re-
calibration sequence. Once the re-calibration is complete, the Model 4500 Premier will exit to
the 'Re-calibration' menu.
9. Unblock the beam on completion of the operation.
10. The Model 4500 Premier is now correctly calibrated. The M203 Clear Stack Simulator option
(if used) requires re-calibration immediately after re-calibration of the instrument.
11. Press and hold the Maintenance key for 1 second until the red LED switches off. The instrument
is now is normal ‘RUN’ mode.
Do not attempt to move the zero point reflector by hand. The precision gearbox will be irreparably
damaged. See section B3-1 for identification.
IMPORTANT: Whenever the Land Service Department is contacted regarding problems with an instrument, please
have available information on the instrument type and serial number . This will enable the department to respond
more accurately and efficiently.