LG RCWW Operation & Maintenance Manual page 109

Temperature sensor(PT-100) problem
Release the temperature sensor connection from the controller and convert the tester to resistance measurement
mode and measure the resistance between A and B, b. The resistance should be between 84.27Ω(-40°C) and
153.58Ω(140°C). (If you check from PT-100 temperature table, you can find the value corresponding to the actual
temperature.)
If the resistance value is outside the measurement boundary, connection is wrong or the sensor is damaged. After
connecting resistance generator(Decade resistance box) to the controller, check whether the temperatures displayed
on the controller change according to the changes of the resistance value; 0°C at 100.00Ω, 10°C at 103.90Ω, and
28°C at 110.9Ω. If normal values are not displayed on the screen, check whether the sensor is set correctly.
If the sensor value does not change when the resistance value is changed, check the main power of the main board
again. If the power is normal and there is no sensor input value, Master or Slave board needs to be replaced.
Temp(°C) Rt (Ω)
-200 18.52
-190 22.83
-180 27.1
-170 31.34
-160 35.54
-150 39.72
-140 43.88
-130 48
-120 52.11
-110 56.19
-100 60.26
-90 64.3
-80 68.33
-70 72.33
-60 76.33
-50 80.31
-40 84.27
-30 88.22
-20 92.16
-10 96.09
0 100
10 103.9
Temp(°C) Rt (Ω)
20 107.79
30 111.67
40 115.54
50 119.4
60 123.24
70 127.08
80 130.9
90 134.71
100 138.51
110 142.29
120 146.07
130 149.83
140 153.58
150 157.33
160 161.05
170 164.77
180 168.48
190 172.17
200 175.86
210 179.53
220 183.19
230 186.84
Table 16 PT-100 Temperature Table
A
B
b
Temperature sensor(PT-100)
Temp(°C) Rt (Ω)
240 90.47
250 194.1
260 197.71
270 201.31
280 204.9
290 208.48
300 212.05
310 215.61
320 219.15
330 222.68
340 226.21
350 229.72
360 233.21
370 236.7
380 240.18
390 243.64
400 247.09
410 250.53
420 253.96
430 257.38
440 260.78
8. TROUBLESHOOTING
109
Temp(°C) Rt (Ω)
450 264.18
460 267.56
470 270.93
480 274.29
490 277.64
500 280.98
510 284.3
520 287.62
530 290.92
540 294.21
550 297.49
560 300.75
570 304.01
580 307.25
590 310.49
600 313.71
610 316.92
620 320.12
630 323.3
640 326.48
650 329.64