Maintenance Alarm; Local Display Unit (Ldc) - Process Sensors MCT Series Installation And Operation Manual

9.5 Maintenance Alarm

The MCT sensor may be fitted with an alarm card with a DC solid-state relay that will activate
whenever any of the sensor's internal alarms are triggered. Refer to the Maintenance Section for a
listing of the alarms that will trigger the alarm contact.
9.6 Dirty Window Alarm
All MCT sensors have a software routine that continually monitors the cleanliness of the sensor's
window. This routine may be activated in the Miscellaneous Menu selection. The routine requires that
on initial installation, when the sensor has a clean window, that this clean state be 'learned' by the
software.
During the operation of the sensor, if the sensor's signals drop to below 70% of the 'learned' clean
window signal, and remain at that level for several minutes, then a warning message will be presented
on the Operator Interface and a digital alarm flag will be sent out the serial port. When this message
appears the window should be cleaned and the 'clean' level re-learned. If the feature is not required it
may be switched off in the Miscellaneous Menu.
9.7 Powder Sampler
The MCT sensor may be fitted with a Powder Sampler that allows the sensor to make measurements on
free falling materials inside enclosed ducts. Refer to Appendix II for complete details of the hardware
and software needed for this Powder Sampler.
9.8 Local Display Unit (LDU)
The LDU is an LED display complete with a 'Grab Sample' button that is intended to be located
alongside the production line close to the sensor and the point where samples will be collected from the
line for calibration verification. The LDU connects to the sensor with a standard interconnecting cable
and has a second cable connector for the Hand Held Operator Interface to connect to. Refer to the rear of
the manual for the outline dimension and mounting detail drawing of the LDU.
The LDU presents the sensor's reading together with a display of the calibration channel being used. In
the front of the unit is a push button switch. This switch initiates a short-term average when a sample is
grabbed.
To initiate the average:
Push the button
The display will show AVG
Grab a sample from the product flow
Push the button again
The display will show the average of the sensor readings since the initial button push.
The value will flash indicating that the value is the average.
After 10 seconds the display will revert to the normal live sensor reading.
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