Detcon TP-700 - Manual (Page 19)

Model TP-700
TP-700 Instruction Manual Rev. 3.5 Page 15 of 38
3.4 Calibration Mode (AutoSpan)
Calibration Mode allows for sensor span calibration. Span calibration should be performed on a routine basis
(quarterly minimum) to ensure reliable performance. If a sensor has been exposed to any de-sensitizing gases
or to very high over-range H
2
S levels, then a re-calibration should be considered. Unless otherwise specified,
span adjustment is recommended at 25ppm for the 0-100 and 0-50ppm ranges (and 10ppm for 0-20ppm
range). This function is called “AUTO SPAN”.
Material Requirements:
 Detcon PN 327-000000-000 MicroSafe™ Programming Magnet
 Detcon PN 613-120000-700 700 Series Splash Guard with integral Cal Port and Calibration Wind
Guard (P/N 943-000000-000) -OR-
 Detcon PN 943-000006-132 Threaded Calibration Adapter
 Detcon PN 985-241100-321 In-Line Humidifying Tube
 Detcon PN 942-010112-025 H
2
S Span Gas (recommended) or other suitable span gas source
containing H
2
S gas in air balance. A fixed flow rate of 200-500cc/min is recommended.
Alternate Span Calibration Methods:
The TP-700 Sensor may also be calibrated with the H
2
S glass ampoule technique. Detcon supplies a
cover for use with the industry standard ampoule breaking cup (available from General Monitors) that
has thread adapter to connect to the TP-700. The adapter cover is Detcon P/N 943-000GMI-CAP.
Remove the Detcon Splashguard and connect the adapter cover firmly in place. Attach the ampoule
breaking cup firmly to the cover with ampoule installed and follow the balance of the instructions for
breaking ampoule and executing AutoSpan.
The TP-700 sensor may also be calibrated using a certified H
2
S gas generator product set for the
correct H
2
S gas level and flow rate.
NOTE 1: Before performing AutoSpan Calibration, verify that the AutoSpan level matches
the span calibration gas concentration as described in Section 3.5.3 Set AutoSpan Level.
NOTE 2: The span gas source must have a normal background concentration of 20.9% O2
(H
2
S balanced with Air). Pure Nitrogen background mixtures are not acceptable! Significant
span calibration inaccuracies will result.
NOTE 3: An H
2
S gas concentration of 25ppm is strongly recommended for 0-50 and 0-
100ppm ranges (10ppm span gas for 0-20ppm range). This should be supplied at a controlled
flow rate of 200 to 500cc/min, with 200cc/min being the recommended flow rate.
Other
concentrations can be used if as they fall within allowable levels.
NOTE 4: Span gas bottles contain 0% humidity and this ultra-low humidity condition will
cause inaccurate readings when used to calibrate a sensor.
To prevent this error, Detcon
prescribes the use of a 24” flexible In-Line Humidifying Tube, which adds the relative
humidity to the span gas. The humidifying tube is not necessary when using a gas generating
calibration device that consists of pumped ambient air and an H
2
S generating source.
NOTE 5: The Calibration Wind Guard must be used when the Splashguard Adapter with
integral Cal Port is used. Failure to use the Calibration Wind Guard may result in an inaccurate