Riken Keiki GD-3EC, Техническое руководство

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10. Product Specifications 10-3 Detection target gases for individual detection principles
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10-3-4 Hot-wire semiconductor type
Sensor
model
Gas name
Gas
symbol
F.S. 1 digit
First
Alarm
setpoint
Second
Alarm
setpoint
Calibration
gas
Operating
temperature
range
Operating
humidity
range
Years of
warranty
SHF-8601 Methane CH
4
5,000 ppm 25 ppm 2,000 ppm 4,000 ppm CH
4
−30 °C - 70 °C
20 %RH -
95 %RH*
(no
condensation)
3 years
SHF-8601
Carbon
monoxide
CO 1,000 ppm 10 ppm 250 ppm 500 ppm CO 0 °C - 70 °C
SHF-8602 Isobutane i-C
4
H
10
2,000 ppm 10 ppm 500 ppm 1,000 ppm i-C
4
H
10
−30 °C - 70 °C
SHF-8603 Hydrogen H
2
2,000 ppm 10 ppm 500 ppm 1,000 ppm H
2
−30 °C - 70 °C
*Absolute humidity not exceeding 46 g/m
3
(equivalent to 37 °C, 95 %RH)
NOTE
 The sensor characteristics may deteriorate significantly if silicone gases (organic silicone gases), halogen
gases, sulfide gases, or acid gases are present.

A silicone removal filter and activated carbon filter are available as options.

Prepare the calibration gas to suit the humidity of the environment in which it will be used.
 When calibrating, allow the product to warm up for a period of time corresponding to the length of time
turned off in clean air before performing zero calibration and span adjustment. For information on
appropriate warmup times, refer to the <Hot-wire semiconductor type sensor warmup times> table below.

The reading may change even for combustible gases other than the detection target gas.
 The reading may change even for ambient fluctuations (e.g., temperature and humidity) in the installation
location.
 The reading may fall as the oxygen concentration decreases.

Interference may occur if gases with high thermal conductivity, such as high-concentration CO
2
, Ar, or He,
are present as the base gas.
 In detecting gases with low vapor pressure by the suction method, the gas may form a mist when drawn
in from the high-temperature side and detected at the low-temperature side, possibly forming
condensation inside the sensor or causing clogging due to sintering. Keep vapor pressure in mind during
use.
 Perform maintenance if a warning appears while the life assessment or self-diagnostic function is active.
 Use the combustible gas sensor adapter when calibrating. Calibration accuracy may be reduced without
the combustible gas sensor adapter.
 Reading accuracy may be reduced if temperature fluctuations exceed ±20 °C with respect to ambient
temperature following zero calibration or span calibration. If this occurs, repeat zero calibration or span
adjustment.

Readings may fluctuate if the product is subjected to strong external impact or vibration. If this occurs,
perform zero calibration and span adjustment.
 The zero point may fluctuate if the sensor comes into contact with high-concentration gas continuously
for extended periods. If this occurs, perform zero calibration and span adjustment.

Readings may fall in environments where gas is continuously present.
 The calibration value may become offset if gas is detected at levels exceeding the F.S. value. Enabling
the sensor protection function will help reduce these effects if there is any possibility of exposure to gas at
levels exceeding the F.S. value. However, if the sensor protection function is enabled, detection is not
possible after the F.S. value has been exceeded until it is reset, as the power to the sensor is cut off.
Reset from the sensor protection state in an environment with clean air.
If the sensor protection state has been used for extended periods (one day or longer), warm up for a
period of time corresponding to the sensor protection period. (Enabling the sensor protection function
also enables the over locking function.)
 The sensor may be hot during replacement. Be careful to avoid burns when replacing the sensor. If the
sensor is hot, turn off the power and wait for it to cool.

Depending on the conditions and length of time for which the power was turned off, the reading may
change when the power is turned on, even after the warmup time (three minutes) has elapsed. If this
occurs, wait until the reading returns to zero.
 Regardless of the detection target gas, the warranty period for SHF sensors is 3 years.