GasSens
Gas Detection System
Section 5 - A11-10 Br2 Sensor/Transmitter
O & M Manual
Revision E, 10/15
5 - 5
CALIBRATION
Sensor/transmitters are factory calibrated for the operating range specified on the order, with the
calibrated range shown on the calibration tag attached inside the lid of the transmitter enclosure. For
critical applications, sensor/transmitters should be calibrated every 3-6 months. When used primarily for
high level leak detection, yearly calibration is probably sufficient. Keep in mind that the best calibration
sources are generally ±10% accurate, and that a sensor/transmitter will normally change sensitivity by less
than 25% over 12 months time.
Calibration of a bromine sensor/transmitter requires a digital volt meter (DVM), a source of
calibration gas (usually an electrochemical chlorine generator) and a calibration adapter for the sensor.
ATI can provide calibration equipment on a rental basis for users who cannot justify the purchase of
calibration equipment. Bromine standards for calibration are not available, but chlorine standards can be
used because a bromine sensor will respond to chlorine on a 1:1 basis. Compressed gas cylinder chlorine
standards are available but should be used with caution. Low concentrations of chlorine have not proven to
be stable in a cylinder over extended periods of time.
NOTE: If alarm relays at the receiver are connected to devices that should not be activated during
calibration, place the receiver into 'alarm inhibit' as described in the Section 2 of this
manual prior to calibrating the sensor/transmitter.
If a sensor/transmitter is equipped with a generator, the generator must be removed prior to
calibration. The generator will unscrew from the sensor. It is not necessary to disconnect the generator
electrical connection from the transmitter circuit board. Once the generator is removed, the calibration
adapter can be attached to the sensor. The calibration adapter slides on to the end of the sensor, and is
connected to the gas source using flexible tubing. The chlorine generator used to calibrate a bromine
sensor is supplied with special tubing to connect to the calibration adapter.
No other type of tubing may
be used
.
Prior to calibration, remove the cover from the sensor/transmitter enclosure and connect a DVM to
the test points shown in Figure 5-2 on the next page. The test points will provide a 0-1.00 VDC signal
proportional to transmitter range. For a standard 0-2 PPM bromine unit, 0 PPM is 0.00 volts and 2.00 PPM
is 1.00 volts.
