Detcon FP-624D - Manual (Page 31)

Model FP-624D
FP-624D Instruction Manual Rev. 1.2 Page 27 of 42
The fault relay can be configured as either latching or non-latching. In non-latching mode, the relay is
deactivated as soon as the fault condition is cleared. In latching mode, the relay remains active even after the
fault condition has cleared. Once activated, the relay can only be deactivated by swiping a magnetic
programming tool above the PGM1 or PGM2 mark on the FP-624D face plate.
The menu item appears as: “Fault Settings”
From the “Fault Settings” text scroll, hold the programming magnet over PGM1 or PGM2 until the “▼”
prompt appears and continue to hold the magnet in place for an additional 3-4 seconds. The display will scroll
“Set Latching”, and then switch to “Yes” or “No”.
“No” indicates the relay is non-latching and “Yes”
indicates the relay is latching. Swipe the magnet momentarily over PGM2 or PGM1 until the correct value is
displayed. Hold the magnet over PGM2 for three seconds to save the setting.
The display will scroll “Set Energized”, and then switch to “Yes” or “No”. “No” indicates the relay is
normally non-energized and “Yes” indicates the relay is normally energized. Swipe the magnet momentarily
over PGM2 or PGM1 until the correct value is displayed. Hold the magnet over PGM2 for three seconds to
save the setting.
Move to another menu item by executing a momentary hold, or, return to Normal Operation via automatic
timeout of about 15 seconds (the display will scroll “Fault Settings” 4 times and then return to Normal
Operation).
3.6 Program Features
Detcon FP-624D 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. The Modbus concentration register will report the measured concentration (up to full scale +
10%).
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. The “In Calibration” bit in the
Modbus fault register is set while the sensor is in calibration mode.
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 and a Modbus register. 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.