Micromod MOD: 30MLTraining Manual - Manual (Page 17)

2 MOD 30ML Operation Lab 2
2.1 Foreword
MOD 30ML can perform complex continuous control as well as discrete control. The
Sequencer block in the MOD 30ML can be used for executing complex batch and
sequencing control. Custom displays can be built for information and operation of the
advanced control.
2.2 Objectives
In this lab we will download a batch control strategy from the memory module to the
MOD 30ML controller and run the batch from the custom displays.
Control of a batch reactor includes sequential and continuous elements, and tight control
of the reaction temperature. Ideally, only one device is used to perform both types of
control, with a common local display interface providing complete process information.
The following demonstration will show:
• integration of automatic sequential and continuous control
• front panel display of sequence steps
• cascade control
• front panel recipe selection and entry of recipe data
• manual control of sequence steps through front panel
2.2.1 The Control System
The batch reaction is conducted according to a definite time-temperature cycle. The next
figure illustrates a typical cycle of many industrial processes.
Reactants are added to the reactor at room temperature; the reaction mass is heated to
reaction temperature; the reaction is carried out to form products; the batch is cooled; and
the reactor is emptied. Total batch time in reactors used in the manufacture of PVC or
polystyrene, for example, is approximately fourteen to eighteen hours. The progression of
the batch cycle is controlled by the sequence operation. It may sometimes be necessary
for the operators to pause, stop, or manually advance the cycle to another step.
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