Ametek Land 4750-PM, User Manual

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5 - 13 User Guide
Particulate Measurement System 4750-PM
5.6.2 Self-check LED
The Self-check LED is used to indicate a sensor check fail (see item 3, Fig.
3-2). The 4750-PM has manually activated sensor performance checks.
During normal operation, if the Self-Check LED turns RED, the Purge Air Flow
check has detected that the purge air flow has stopped or is insufficient.
Connection Description
GREEN (solid) Sensor checks PASS
GREEN (flashing) Sensor checks RUNNING
RED (solid) A sensor check has failed (Relay 1 activates).
5.6.3 Viewing Sensor Check Results
For information on initiating sensor checks manually from the sensor refer
to Section 5.2.9. Refer to the Standard or Engineering menu maps (Sections
5.2 and 5.3 respectively).
1) If required, select the
DUST menu, then press RIGHT repeatedly to
display each self-check and the current reading (see table below for
details).
2) Press RIGHT to return to the main menu or press LEFT to return to the
previous setting.
Sensor Check Reading Displayed
ZERO Zero test result
SPAN Span (or Upscale) test result
FLOW Purge air flow test result (if available)
5.7 Auditing the Sensor
The Manual Audit Unit (MAU) is a standalone unit that is used to audit the
instrument to ensure operational performance. The MAU is a single-value,
compact audit kit or block. The audit unit filter is calibrated to yield a
different instrument response; the value is labelled on the front of the MAU.
The MAU is attached to the sensor body opening (see Fig. 5-4) to check
the optical path and measure the instrument’s response to a stable scatter
source.
5.7.1 High-Range Audit Value Units
Audit units with a high-range audit value (ACCAUD-XXX-1-300) are marked
with a label (see Fig. 5-3). If an audit unit has been calibrated for a high-
range setting, ensure that the LPUR (laser power) setting is set to ‘ON’
before commencing the audit check.
NOTE
Laser power may already be set to ‘ON’ for normal operation.
Therefore, when the audit check is complete, always return LPUR
to its initial setting (see Section 5.4.4 for details).