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Grain-Watch
Grain-Watch

Grain-Watch® Fan Relay Unit

Combined with the Outdoor Temperature Sensor GW-rHS01 and the PC Software, the Grain-Watch® PLCK-USB Fan Relay is used for automatic silo aeration. When the trip levels for relative air humidity, air temperature and grain temperature set in the software are triggered, the GW-PLCK-USB Fan Relay starts silo aeration automatically. The unit is available with 4, 10, and 26 relay outputs. The GW-PLCK-USB Fan Relay connects to the PC via two USB ports.

Fan Control

When aerating silo bins, knowing the grain temperature, air temperature and relative air humidity are vital. Blowing air that is warmer than the stored grain into the silo means raising the grain's moisture content and temperature, and diminishing its commercial value.

  Grain Temperature in Celsius
Cooling Air Temperature in Celsius
  -6°C -4°C -2°C ±0°C 2°C 4°C 6°C 8°C 10°C 12°C 14°C 16°C 18°C 20°C 22°C 24°C 26°C 28°C 30°C
-8°C 88 - - - - - - - - - - - - - - - - - -
-6°C 75 88 - - - - - - - - - - - - - - - - -
-4°C 64 75 88 - - - - - - - - - - - - - - - -
-2°C 54 64 75 87 - - - - - - - - - - - - - - -
0°C 46 54 64 75 87 - - - - - - - - - - - - - -
2°C 40 46 55 65 75 86 98 - - - - - - - - - - - -
4°C 35 41 48 57 66 75 86 97 - - - - - - - - - - -
6°C 31 36 43 50 58 66 75 85 97 - - - - - - - - - -
8°C 27 32 37 44 51 58 66 75 85 97 - - - - - - - - -
10°C 24 28 33 38 45 51 58 66 75 85 97 - - - - - - - -
12°C 21 25 29 34 38 45 51 58 66 75 85 95 - - - - - - -
14°C 19 22 26 30 35 40 46 52 58 66 75 85 95 - - - - - -
16°C 17 19 23 27 31 35 40 46 52 59 66 75 85 95 - - - - -
18°C 15 17 20 24 27 31 36 41 46 52 59 66 75 84 95 - - - -
20°C 13 15 18 21 24 28 32 36 41 46 53 59 67 75 84 95 - - -
22°C 12 14 16 19 22 25 28 32 36 41 47 53 60 67 75 84 94 - -
24°C 10 12 14 17 19 22 25 29 32 37 42 47 53 60 67 75 84 94 -
26°C 9 11 13 15 17 20 23 26 29 33 37 42 47 53 60 67 75 84 93
28°C 8 10 11 13 15 18 20 23 26 30 33 38 42 48 55 60 67 75 84
  Source: Lantmännen, “Safe Grain Storage,” 2007

Use the data table as follows:

If the point of intersection between the Cooling Air Temperature and the Grain Temperature coincides on a blank field in the data table, there is no risk of raising the grain's moisture content. If the point of intersection coincides on a field with a numeric value, the relative air humidity must be lower than that value to avoid raising the grain moisture content. The data table indicates air humidity in percent RF%.

Download the table as Pdf
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