Teledyne 700 IR Series Instruction Manual page 36

700 IR Series
INFRARED GAS DETECTOR FOR COMBUSTIBLE AND CO
2
GASES
USER MANUAL
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 as a RS-485 Modbus
register bit. 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.
3.6.2 Fault Diagnostic/Fail-Safe Features
Fail-Safe/Fault Supervision
OLCT 700/710 IR detectors are designed for Fail-Safe operation. If any of the diagnostic faults
listed below are active, the display will scroll the message "Fault Detected" every 30 seconds
during normal operation. At any time while the "Fault Detected" message is active, swipe the
magnet over PGM1 or PGM2 to display the active fault(s). All active faults will then be reported
sequentially.
Most fault conditions result in failed operation of the detector and in those cases the 4-20mA
signal is dropped to the universal fault level of 0mA. These include Zero Fault, AutoSpan
Calibration Faults, Sensor Fault, Processor Fault, Memory Fault, Loop Fault, and Input Voltage
Fault. The 0mA fault level 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 1: Refer to the Troubleshooting Guide in section 6 for guidance on fault conditions.
Zero Fault
If the detector 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 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 detector should be considered "Out-of-Service" until a successful
AutoZero calibration is performed.
Range Fault – AutoSpan
If the detector fails the minimum signal change criteria during AutoSpan sequence (Section 0) the
"Range Fault" will be declared. A "Range Fault" will cause a "Fault Detected" message to scroll
once a minute on the 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 detector should
be considered "Out-of-Service" until a successful AutoSpan calibration is performed.
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NP700IRIMEN
Revision E.0