TGS2442 Datasheet, PDF (18/25 Pages) List of Unclassifed Manufacturers – Detection of Carbon Monoxide

CALIBRATION OF TGS2442
Figure 1 - Basic circuit (including trouble detection)
Figure 2 - Calibration & temperature compensation
Legend of Circuit Diagrams
S-In
H-In
R-In
8-bit A/D input port
8-bit A/D input port
8-bit A/D input port
(Each of these ports acquires data at preset timing.)
RL1
RL2
Pulse
Temp
Calb
open drain output port
open drain output port
open drain output port
open drain output port
open drain output port
Revised 04/01
Circuit voltage (Vc) across the sensor is applied when RL1 or RL2
ports give the Low (L) output signal at preset timing.
V1 and V2 are acquired during the last half of the 5msec VC pulse
(the first half of the VC pulse is considered as the transient period).
V5 is acquired during heater OFF, and V6 is acquired during heater
ON pulse.
RA = closest value to Rs at calibrated CO concentration
RB = 300kΩ
RC = 10kΩ
RD = 20kΩ
VRadj = 100kΩ
Thermistor: R (25˚C) = 15kΩ, B constant = 4200
3