Detcon FP-524D-HRT - Manual (Page 28)

Model FP-524D-HRT
FP-524D-HRT Instruction Manual Rev. 0.1 Page 24 of 48
NOTE: For FP-524D sensors that have the HRT Bridge Interface installed, an active fault will
cause the mA output to drop to 1mA to signify a sensor fault.
NOTE: Refer to the Troubleshooting Guide, Section 6, for guidance on fault conditions.
Zero Fault
If the sensor drifts below –10% LEL, the “Zero Fault” will be declared. A “Zero Fault” will cause a “Fault
Detected” message to scroll once a minute on the transmitter display and drop the 4-20mA output to 0mA.
The sensor should be considered “Out-of-Service” until a successful AutoZero calibration is performed.
Range Fault – AutoSpan
If the sensor fails the minimum signal change criteria during AutoSpan sequence (Section 3.4), the “Range
Fault” will be declared. A “Range Fault” will cause a “Fault Detected” message to scroll once a minute on the
sensor display and drop the 4-20mA output to 0mA. The sensor should be considered “Out-of-Service” until a
successful AutoSpan calibration is performed.
Stability Fault - AutoSpan
If the sensor fails the signal stability criteria during AutoSpan sequence (Section 3.4), the “Stability Fault” will
be declared. A “Stability Fault” will cause a “Fault Detected” message to scroll once a minute on the sensor
display and drop the mA output to 0mA.
The sensor should be considered as “Out-of-Service” until a
successful AutoSpan calibration is performed.
Clearing Fault - AutoSpan
If the sensor fails the signal stability criteria during AutoSpan sequence (Section 3.4), the “Clearing Fault” will
be declared. A “Clearing Fault” will cause a “Fault Detected” message to scroll once a minute on the sensor
display and drop the mA output to 0mA.
The sensor should be considered as “Out-of-Service” until a
successful AutoSpan calibration is performed.
Sensor Current Fault
If the current through the sensor bridge (See Figure 3) drifts outside the range of 200mA ± 50mA, a “Sensor
Current Fault” will be declared. A “Sensor Current Fault” will cause a “Fault Detected” message to scroll
once a minute on the transmitter display. If a Sensor Current Fault occurs, the 4-20mA signal will be set at
0mA until the fault condition is resolved.
Sensor Voltage Fault
If the voltage across the sensor bridge (See Figure 3) is greater than 3.5VDC or less than 1.8VDC, a “Sensor
Voltage Fault” will be declared. A “Sensor Voltage Fault” will cause a “Fault Detected” message to scroll
once a minute on the transmitter display. If a Sensor Voltage Fault occurs, the 4-20mA signal will be set at
0mA until the fault condition is resolved.
Processor Fault
If the detector has any unrecoverable run-time errors, a “Processor Fault” is declared. A “Processor Fault”
will cause a “Fault Detected” message to scroll once a minute on the sensor display. If a Processor Fault
occurs, the 4-20mA signal will be set at 0mA until the fault condition is resolved.