AUTOMATIC IMBIBITION CONTROL SYSTEM:

The fibre percentage in sugar cane varies from variety to variety, field to field and from period to period hence it becomes very difficult to keep track of precious Sugar lost in the
bagasse if imbibed water is insufficient, on the other hand if over imbibed the Boiler and Boiling House efficiency reduces and it is almost impossible to monitor this manually.

Control Philosophy:

It is a common belief that the best solution for Automatic Imbibition Control is to monitor last Mill Juice Brix. Brix is the percentage of solid matter in a solution indicated by any densimetric
method, and is analogous to the electrical conductivity of that solution. But in case of Cane Juice, this electrical conductivity also varies due to several other factors because Sugar Cane is
harvested from different fields with a variety of soils of different chemical compositions which vary the electrical characteristics of Cane Juice and hence corrupt the true Brix reading.

To avoid these erratic & erroneous signals, we co-relate Brix to load on last but one Mill and its Top Roller Lift and then compare it with the water flow to derive a control signal.

Here the load on the mill is represented by its chest presssure in case of steam turbine, currenti n case of DC motor or hydraulic pressure in case of hydraulic drive, which represents the
instantaneous crushing rate.

Both signals are fed to the Fuzzy Logic PID Controller where they are internally summed up, the resultant is treated as a remote set variable and is compared with the instantaeous flow rate,
control valve position and the set factor (in terms of % water on cane which can be set/changed by the user). The result of this comparison is termed as the error which is continually
rectified by the PID Controller by imparting corrective signal on the Control Valve.