Detcon FP-700 - Manual (Page 29)

Model FP-700
FP-700 Instruction Manual Rev. 3.0 Page 25 of 40
is not employed for a Temperature Fault and AutoSpan Reminder Fault. For all diagnostic faults, the
associated RS-485 Modbus™ fault register will be flagged to alert the user digitally.
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 ITM display and drop the 4-20mA output to 0mA. The
Modbus™ fault register bit for Zero Fault will be set and will not clear until the fault condition has been
cleared.
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 (Section 3.4.2) change criteria during AutoSpan sequence, the “Range
Fault” will be declared. A “Range Fault” will cause a “Fault Detected” message to scroll once a minute on the
ITM display and drop the 4-20mA output to 0mA. The Modbus™ fault register bit for Range Fault will be set
and will not clear until the fault condition has been cleared. 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 (Section 3.4.2) during AutoSpan sequence, the “Stability Fault”
will be declared. A “Stability Fault” will cause a “Fault Detected” message to scroll once a minute on the ITM
display and drop the mA output to 0mA. The Modbus™ fault register bit for Stability Fault will be set and
will not clear until the fault condition has been cleared. The sensor should be considered as “Out-of-Service”
until a successful AutoSpan calibration is performed.
Clearing Fault - AutoSpan
If the sensor fails the clearing criteria (Section 3.4.2) during AutoSpan sequence, the “Clearing Fault” will be
declared. A “Clearing Fault” will cause a “Fault Detected” message to scroll once a minute on the ITM
display and drop the milliamp output to 0mA. The Modbus™ fault register bit for Clearing Fault will be set
and will not clear until the fault condition has been cleared. The sensor should be considered as “Out-of-
Service” until a successful AutoSpan calibration is performed.
Sensor Fault
If either the active or reference detector should fail and become electrically open or the sensor was missing, a
“Sensor Fault” will be declared. A “Sensor Fault” will cause a “Fault Detected” message to scroll once a
minute on the ITM display. The Modbus™ fault register bit for Sensor Fault will be set and will not clear
until the fault condition has been cleared. If a Sensor 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 ITM display. The Modbus™ fault
register bit for Processor Fault will be set and will not clear until the fault condition has been cleared. If a
Processor Fault occurs, the 4-20mA signal will be set at 0mA until the fault condition is resolved.
Memory Fault
If the detector has a failure in saving new data to memory, a “Memory Fault” is declared. A “Memory Fault”
will cause the “Fault Detected” message to scroll once a minute on the ITM display. The Modbus™ fault