Grain Systems PNEG-1851 - Manual (Page 61)

Chapter 7: The Continuous Flow Drying Process
Inner Temperature Offset — The small temperature offset, used to obtain the pair of temperature
values that are closest to the reference temperature. One value is equal to reference temperature
minus this offset, whereas the other is equal to the reference temperature plus this offset.
Outer Temperature Offset — The large temperature offset, used to obtain the pair of temperature
values that are furthest from the reference temperature. One value is equal to reference temperature
minus this offset, whereas the other is equal to the reference temperature plus this offset.
Reference Speed — The metering roll’s setpoint (or reference) speed. This is the only true speed
parameter that you set; the others are offsets of this value.
Inner Speed Offset — The small speed offset, used to obtain the pair of speed values that are clos-
est to the reference speed. One value is equal to reference speed minus this offset, whereas the
other is equal to the reference speed plus this offset.
Outer Speed Offset — The large speed offset, used to obtain the pair of speed values that are fur-
thest from the reference speed. One value is equal to reference speed minus this offset, whereas the
other is equal to the reference speed plus this offset.
Let’s assume that you enter the following values: a reference temperature (T3) of 90°F; an inner tempera-
ture offset (T2, T4) of 1°F; an outer temperature offset (T1, T5) of 3°F; a reference speed (S3) of 50%; an
inner speed offset (S2, S4) of 5%; an outer speed offset (S1, S5) of 10%.
When the grain’s actual temperature reading is at 90°F (T3), the metering rolls turn at the reference speed
of 50% (S3). If the grain temperature rises to 91°F (T4), the metering roll speed increases to 55% (S4). If
the grain temperature continues to climb to 93°F (T5), the metering roll speed increases to 60% (S5), thus
allowing the grain to exit the drying chamber more rapidly. When the grain temperature drops back below
93°F, the metering roll speed starts to decrease back to the reference speed setpoint.
After You Finish
Now that the control scheme is set, complete the procedure on drying grain in continuous flow mode (see
Drying Grain in Continuous Flow, page 57 ).
Setting the 5-Speed Moisture Scheme in Continuous Flow
To regulate the grain moisture within the dryer by automatically switching between five different metering
roll speeds, you can select the 5-speed moisture scheme when the wet grain’s moisture varies consider-
ably across the grain spread.
Before You Begin
Make sure to select the 5-Speed Moisture control scheme in the Moisture Control Mode window (see
Drying Grain in Continuous Flow, page 57 for details).
What You Should Know
It is recommended to use the 5-speed moisture control scheme if you are operating in full-heat and the
moisture content of the incoming wet grain varies by three percentage points or more across the grain
spread. Due to the inherent delays between drying, cooling, and unloading grain in the dry and cool opera-
tion, and that moisture levels are only monitored at the unload section, this control scheme is not recom-
mended when operating in dry and cool.
To set the 5-speed moisture control scheme in continuous flow:
1. If the dryer is running, press Stop on the control panel.
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