Datasheet

Revised 08/12
12
TECHNICAL INFORMATION FOR TGS3870
0.1
1
10
0 1 2 3 4 5 6 7 8
Methane 1000ppm
Methane 3000ppm
Methane 9000ppm
Rs/Ro
Time (days)
test
8 hours after test
0.01
0.1
1
10
0 1 2 3 4 5 6 7 8
CO 100ppm
CO 300ppm
CO 900ppm
Rs/Ro
Time (days)
test
8 hours after test
Figure 15b - Temperature cycle test effects on CO sensing
(Ro = Rs in 100ppm of CO at Day=0, VH =0.2)
3-5 Temperature cycle test
In accordance with UL2034, Sec. 41.1(e)-Stability Test,
test samples were exposed to ten cycles (<1 hour and
> 15 minutes) of temperature from 0˚C and 100%RH
to 49˚C and 40%RH. As the two test measurements
taken 8 hours after the conclusion of the test period
demonstrate, sensors subjected to this test show
negligible inuence on CO and methane sensing by
temperature extremes.
4. Cautions
4-1 Situations which must be avoided
1) Exposure to silicone vapors
If silicone vapors adsorb onto the sensor’s surface, the
sensing material will be coated, irreversibly inhibiting
sensitivity. Avoid exposure where silicone adhesives,
hair grooming materials, or silicone rubber/putty
may be present.
2) Highly corrosive environment
High density exposure to corrosive materials such
as H2S, SOx, Cl2, HCl, etc. for extended periods may
cause corrosion or breakage of the lead wires or
heater material.
3) Contamination by alkaline metals
Sensor drift may occur when the sensor is contam-
inated by alkaline metals, especially salt water spray.
4) Contact with water
Sensor drift may occur due to soaking or splashing
the sensor with water.
5) Freezing
If water freezes on the sensing surface, the sensing
material would crack, altering characteristics.
6) Application of excessive voltage
If higher than specied voltage is applied to the
sensor or the heater, lead wires and/or the heater may
be damaged or sensor characteristics may drift, even
if no physical damage or breakage occurs.
7) Operation in zero/low oxygen environment
TGS sensors require the presence of around 21%
(ambient) oxygen in their operating environment in
order to function properly and to exhibit characteristics
described in Figaro’s product literature. TGS sensors
cannot properly operate in a zero or low oxygen
Figure 15a - Temperature cycle test effects on
methane sensing
(Ro = Rs in 3000ppm of CH4 at Day=0, VH =0.9)
Rs/Ro Rs/Ro