Detcon FP-524D-HRT - Manual (Page 27)

Model FP-524D-HRT
FP-524D-HRT Instruction Manual Rev. 0.1 Page 23 of 48
NOTE: The following must be performed in order before the sensor can be placed back into
operation.
 AutoSpan Level = 50 %LEL. AutoSpan level must be set appropriately by the operator (Section 3.5.2).
 Gas Factor = 1.0. The Gas Factor must be set appropriately by the operator (Section 3.5.3).
 Cal Factor = 1.0. The Cal Factor must be set appropriately by the operator (Section 3.5.4).
 AutoZero: AutoZero Settings are lost and user must perform new AutoZero (Section 3.4.1).
 AutoSpan: AutoSpan Settings are lost and user must perform new AutoSpan (Section 3.4.2).
3.6 Program Features
Detcon FP-524D-HRT combustible gas sensors incorporate a comprehensive set of diagnostic features to
achieve Fail-Safe Operation. These Operational features and Failsafe Diagnostic features are detailed below.
3.6.1 Operational Features
Over-Range
When gas greater than the full-scale range is detected, the sensor display will continuously flash the full-scale
reading of 100. This designates an over-range condition. The 4-20mA signal will report a 22mA output
during this time.
In-Calibration Status
When the sensor is engaged in AutoZero or AutoSpan calibration, the 4-20mA output signal is taken to
2.0mA. This alerts the user that the sensor is not in an active measurement mode. This feature also allows the
user to log the AutoZero and AutoSpan events via their master control system.
Sensor Life
Sensor Life is calculated after each AutoSpan calibration and is reported as an indicator of remaining service
life. It is reported in the “View Sensor Status” menu. Sensor Life is reported on a scale of 0-100%. When
Sensor Life falls below 25%, the sensor cell should be replaced within a reasonable maintenance schedule.
Last AutoSpan Date
This reports the number of days that have elapsed since the last successful AutoSpan. This is reported in the
View Sensor Status menu. After 180 days, an AutoSpan Fault will be declared.
3.6.2 Fault Diagnostic/Failsafe Features
Fail-Safe/Fault Supervision
Model FP-524D-HRT MicroSafe™ sensors are designed for Fail-Safe operation. If any of the diagnostic
faults listed below are active, the sensor display will scroll the message “Fault Detected” every 60 seconds
during normal operation. At any time during “Fault Detected” mode, holding the programming magnet over
PGM1 or PGM2 for 1 second will display the active fault(s). All active faults are reported sequentially.
Most fault conditions result in failed operation of the sensor. In these cases the 4-20mA signal is dropped to
the universal fault level of 0mA. These include the AutoZero and AutoSpan Calibration faults, Sensor Faults,
Processor Fault, Memory Fault, Loop Fault, and Input Voltage Fault. (The 0mA fault level is not employed
for a Temperature Fault, or during Calibration.)