Det-Tronics THZ HART Combustible Gas Transmitter - Manual (Page 4)

CONFIGURATION USING HART COMMUNICATION
The DEC-THZ gas detector is shipped from the facto-
ry pre-configured. If it is necessary to change any
HART configurations, the following items are required:
1. 275 handheld HART communicator with the
Device Descriptor (DD) software.
— OR —
2. THZ configuration software loaded into a
Windows based PC and a HART modem (as man-
ufactured by SMAR Research Corp., Model HI311
HART Serial Interface).
Using either of these HART communication devices, it
is possible to change the HART configuration param-
eters of the DEC-THZ gas detector. Contact Detector
Electronics for copies of the DEC-THZ configuration
program.
CAUTION
Changing certain HART configuration parameters
such as input/output range and custom response
curve data will result in improper operation of the
DEC-THZ gas detector.
CALIBRATION
CALIBRATION RECOMMENDATIONS
When to Perform Calibration
• When a new system is initially put into service.
• When the sensor is replaced.
• Periodically to verify proper sensor performance —
typically at 90 day intervals, however, this frequency
is dependent upon the requirements of each appli-
cation. Refer to Table 1 for the recommended cali-
bration frequency for DEC sensors.
Calibration Gas Sources
For optimum performance, only use Det-Tronics cali-
bration gases.
For toxic gas sensor calibration, the calibration gas
type must match the sensor cell type. The calibration
gas concentration should be one half of the full scale
measurement range of the sensor in use.
For oxygen sensor calibration, normal ambient air
may be used for span calibration if it is known to be
clean and not depleted of O2 (21% vol.).
Compressed clean air is available from Det-Tronics if
required. It is not necessary to utilize an O2 free gas
such as compressed nitrogen to calibrate the O2 sen-
sor zero level. An electronic zero switch is provided
within the C7065E sensor housing for this function.
Refer to the O2 sensor instruction manual for details.
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Table 1—Recommended Frequency of Calibration for DEC Sensors
Req = Required
Opt = Optional
NR = Not Recommended
Sensor Type After 1 Hour Warm-up After 24 Hours After 1 Week Every 90 Days
H2S Req Opt Opt Opt
Chlorine Req Req NR Req
Oxygen Req Opt Opt Opt
Carbon Monoxide Req Opt Opt Opt
Nitrogen Dioxide Req Opt Opt Opt
Sulfur Dioxide Req Opt Opt Opt