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Honeywell CRIR-E1 User Guide
Table 4 - Termination - I/O Options Dedicated to the CRIR E1 (continued)
PIN NUMBER PIN FUNCTION DESCRIPTION ELECTRONIC SPECIFICATION
5bCAL_in
/CAL
Digital input forcing background or zero
calibration
Background calibration: When closed for
minimum 4 s, maximum 8 s, bCAL
(background calibration) assuming 400
ppm CO2exposure.
Zero calibration: when closed for
minimum 16 s CAL (zero calibration)
assuming 0 ppm CO2
exposure
Absolute maximum voltage range1
Internal pull down to GND resistor
Input low level1
Input high level1
No internal protection, pulled up to VDD2
at processor reset (power up and power
down)
GND to VDD + 0.5 V
120 k
GND to 0.75 V
2.3 V to VDD + 0.3 V
6PWM
PWM output congured as digital output
used fordirect reading by customer’s
microcontroller or to provide analog
output.
Normal concentration range
PWM cycle time
Beginning of each cycle
End of each cycle
Relationship between CO2concentration
(ppm) and PWM output
PWM resolution
Absolute maximum voltage range1
Internal pull down to GND resistor
Output low level1
Output high level1
No internal protection, pulled down at pro-
cessor reset (power up and power down)
400 ppm to 2000 ppm
1004 ms ± 5%
high level output, 2 ms
low level output, 2 ms
C(CO2) = 2000 x (TH - 2) / (TH + TL - 4)
TH: time (ms) of high level output in a cycle
TL: time (ms) of low level output in a cycle
0.5 ms ± 4%
GND to VDD + 0.5 V
120 k
0.4 VDC maximum at 8 mA sink
2.4 VDC minimum at 8 mA source
7Alarm_OC
Open collector output for alarm indication
Absolute maximum voltage range1
Internal pull up to G+ resistor
Maximum sink current1
Saturation voltage1
no internal protection, pulled up to G+
at processor reset (power up and power
down)
GND to 5 V + 0.5 V
10 k
100 mA
2.3 V to Vin + 0.3 V
1 The specied parameter relies on the subcontractor's specication and is not tested by Honeywell.
CALIBRATION
With the ABC function on, the sensor readings, which may have drifted due to mishandling during
transportation and/or installation, may gradually be recalibrated to the correct numbers. However, in
case the user cannot wait for several cycles of ABC to run, the two quick manual calibrations given in
5.1 and 5.2 may be performed.