Panasonic CU-PW9DKE Service Manual page 23

8.5 Air Quality Sensor Control
Resistance of air quality sensor: Rs(air)=10k ~50k ( The worse the air quality, the smaller the resistance.)
Basic Operation
Detecting and indicating of the air quality will not stop during the operation of the air conditioner.
The power of the air quality sensor is always on during the operation of the air conditioner. When the air
conditioner stops (The air conditioner is on standby.), the air conditioner will provide power to the air quality
sensor intermittently (It will be on for 3 minutes after each 109 minutes.) for the purpose of air quality detecting.
Within 2 minutes after the air conditioner starts to operate, the air quality sensor is in the process of preheating
and the air quality indicator is red.
Resistance Reference
Detecting of air quality( During the operation of the air conditioner)
(a) The measuring period is 20 minutes; The air conditioner will measure the resistance (Rs) of the air quality
sensor once each 2 seconds and record the data. The maximum Rs within the 20 minutes will be selected as
Rs(MAX) for this measuring period.
(b) Suppose the current Rs(MAX) as MAX and the resistance reference of the previous measuring period is as
MAXR1.; If MAX>MAXR1, the resistance reference of the current measuring period is MAXR=MAX; If
MAX<MAXR1, MAXR=MAXR1;
(c) Within 2 minutes after the power of the air quality sensor is turned on, the resistance reference of this
measuring period is the maximum resistance of the sensor during this period.
Maximum of Rs
MAXR1 of previous
measuring period
Updating of MAXR
The following conditions should be fulfilled
(d)
The initial MAXR after the preheating of the air quality sensor when the air conditioner is turned on:
The air conditioner will compare the maximum value of the current measuring period (MAX) with the
resistance reference 109 minutes before ( MAXR0) and select the bigger one as the current resistance
(e)
reference(MAXR).
When the air conditioner determines the air quality is getting worse: Air quality level 1
MAXR will not be updated; When the air quality gets better (air quality level 0), Rs detected at this time will be
(f)
MAX and MAXR.
The air conditioner will not detect the air quality during deicing operation. The indication prior to the deicing
operation will be held during the deicing operation.
20minutes
MAX1
MAX0
MAX1 MAX0 MAX0
MAX1 MAX0 MAX1
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CS-PW9DKE / CU-PW9DKE / CS-PW12DKE / CU-PW12DKE
20minutes
MAX2
MAX1
MAX2 MAX1 MAX1
MAX2 MAX1 MAX2
20minutes
MAX3
MAX2
MAX3 MAX2 MAX2
MAX3 MAX2 MAX3
Air quality level 2,