Emerson Net Safety SC311, Reference Manual

Page: 16 / 36

Reference Manual Installation
MAN-0091, Revision 8 June 2016
Installation 9
2.7 Calibration
The Net Safety SC311 sensor should be powered up for at least twenty-four (24 hours) prior to
completing the first calibration.
Calibration of the infrared sensor must be completed with the target gas for the application and the gas
the SC311 is programmed for. The calibration gas can be either air or nitrogen balanced.
Calibration of the SC311 should be completed every twelve (12) months. In environments where the
sensor may be routinely exposed to gas concentrations or airborne contaminants, the sensor should be
verified or calibrated on a more frequent basis. The SC311 sensor must be calibrated with calibration
gas at temperatures between -15°C and +45°C (+5°F and 113°F) to meet its accuracy specification.
Since external factors can affect the SC311 sensor’s ability to properly detect gas, it is highly
recommended that quarterly inspections and bump tests be completed to ensure proper operation of
the gas detection system.
If accessories are used on the SC311, calibrations must be completed with these accessories in place.
There are specific steps to be followed when calibrating with a Millennium II Transmitter. Refer to the
appropriate transmitter manual that the sensor is connected to for calibration procedures. These steps
should be followed if accurate results are to be obtained.
2.7.1 Gas curves
Infrared gas sensors need to be set up for the target gas in the particular application. The SC311 has a
number of primary gases available as shown in
Table 2-2 . When connected to a Millennium II
transmitter, these gas curves can be selected through the main display and need to be selected prior to
performing a calibration. For Millennium II Basic transmitters, DIP switches corresponding to the target
gas need to be set. Refer to
3.4 for more information.