Model TP-700
TP-700 Instruction Manual Rev. 4.1 Page 17 of 42
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
balanced with Air). Pure Nitrogen background mixtures are not acceptable! Significant span
calibration inaccuracies will result.
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.
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