LG LCWW, Operation & Maintenance Manual, Page: 109 / 119

109
8. TROUBLESHOOTING
ENGLISH
Temperature sensor(PT-100) problem
Temperature sensor(PT-100)
A
B
b
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 84.27
Ω
(-40°C) and
153.58
Ω
(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 100.00
Ω
, 10°C at 103.90
Ω
, and
28°C at 110.9
Ω
. 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
) Temp(°C) Rt (
Ω
) Temp(°C) Rt (
Ω
) Temp(°C) Rt (
Ω
)
-200 18.52 20 107.79 240 90.47 450 264.18
-190 22.83 30 111.67 250 194.1 460 267.56
-180 27.1 40 115.54 260 197.71 470 270.93
-170 31.34 50 119.4 270 201.31 480 274.29
-160 35.54 60 123.24 280 204.9 490 277.64
-150 39.72 70 127.08 290 208.48 500 280.98
-140 43.88 80 130.9 300 212.05 510 284.3
-130 48 90 134.71 310 215.61 520 287.62
-120 52.11 100 138.51 320 219.15 530 290.92
-110 56.19 110 142.29 330 222.68 540 294.21
-100 60.26 120 146.07 340 226.21 550 297.49
-90 64.3 130 149.83 350 229.72 560 300.75
-80 68.33 140 153.58 360 233.21 570 304.01
-70 72.33 150 157.33 370 236.7 580 307.25
-60 76.33 160 161.05 380 240.18 590 310.49
-50 80.31 170 164.77 390 243.64 600 313.71
-40 84.27 180 168.48 400 247.09 610 316.92
-30 88.22 190 172.17 410 250.53 620 320.12
-20 92.16 200 175.86 420 253.96 630 323.3
-10 96.09 210 179.53 430 257.38 640 326.48
0 100 220 183.19 440 260.78 650 329.64
10 103.9 230 186.84
Table 16 PT-100 Temperature Table