Reducing engineering efforts by using control strategies in Batch Control

Introduction

The Batch Control module allows the simple creation of receipes, even large recipes with a lot phases, whilst still keeping an overview. However, keeping the number of phases low can help you save time and effort, not only for creating the zenon project, but also for developing the PLC program. With control strategies, which were introduced in zenon 7.11, you can reduce the number of phases without losing any of the flexibility of your Batch Control solution.

The benefits of using Control Strategies

In your project you might have some phases which are quite similar. Let’s use the phases “heat”, “cool” and “keep temperature” as an example. They have quite a few things in common:

  • Value tags: even though they might have different values, some of the value tags are common.
  • Return tags: the same actual values might be of interest for all phases.
  • Status tags (command and return): every phase needs to be synchronized with the corresponding PLC program (equipment control).
  • Conditions and Reactions: such as the status tags; these are used to synchronize the phase with the PLC program. They are equal in all original phases.

Control Strategies in Batch Control

The goal of control strategies is to create and maintain the common properties only once, while allowing the modification of properties which distinguish the original phases independently.

How to use Control Strategies

If you decide to use control strategies, you will first need some kind of “master” phase which includes all the tags and reactions of the original phases – we will use the example “temp control”. Then activate the control strategies property of the phase. Now you can create control strategies as sub-elements of the phase and link the required value tags to them. All return tags, reactions and conditions will automatically be applied to each control strategies.

Summary

Control strategies allow you to reduce the number of phases in your zenon project and the number of programs in the PLC. This will reduce the workload when you initially create the project and also when you need to make changes later on. As a consequence, control strategies will help you to avoid errors.

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