Detcon TP-700 - Manual (Page 26)

Model TP-700
TP-700 Instruction Manual Rev. 3.5 Page 22 of 38
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 “Restore Defaults” 4 times and then return to Normal
Operation).
Following the execution of “Restore Defaults”, the TP-700 will revert to its factory default settings. The
default settings are:
 Serial ID = 01. The Serial ID must be set appropriately by the operator (3.5.5).
NOTE: The following must be performed in order before the sensor can be placed in operation.
 Range = 100ppm. Range must be set appropriately by the operator (3.5.4).
 AutoSpan Level = 25ppm. AutoSpan level must be set appropriately by the operator (3.5.3).
 Heater Power: Heater Power settings are lost and “Set Heater Power” (3.5.6) must be performed before
“AutoSpan”.
 AutoSpan: AutoSpan Settings are lost and a successful “AutoSpan” must be performed before placing the
Sensor into operation (3.4).
3.6 Program Features
Detcon TP-700 H
2
S 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 ITM display will continuously flash the full-scale
reading (20, 50, 100ppm, 200ppm). 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 AutoSpan calibration, the 4-20mA output signal is taken to 2.0mA and the in-
calibration Modbus™ Status Register bit 14 is set. This alerts the user that the ITM is not in an active
measurement mode. This feature also allows the user to log the 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 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. After 180 days, an AutoSpan Fault will be declared.
3.6.2 Fault Diagnostic/Failsafe Features