Phase Block Components

You can use a provided AVEVA Batch Management template to assist in phase block structuring. The phase block code consists of six sections, as shown in the following diagram.

The diagram shows the components in a distinct order. We recommend this order for sequential processing control systems. For control systems that are capable of parallel processing, the flow of information can be different.

Phase Control

This section of the phase block manipulates the phase control bits needed to operate the phase logic. AVEVA Batch Management System enables the appropriate control word within the control system associated with a particular phase block. The phase logic must be written to interpret this word and resolve the individual control bits of the word to the start, restart, hold, abort, and reset commands.

We recommend that the phase logic reset the control word so that the next requested function can be recognized. Thus, the control bits are essentially one time only commands.

You must include this section for every Automatic and Semi-Automatic phase block.

Control Buttons

The section of the phase block that corresponds to the control buttons is constructed similarly to the phase control section. AVEVA Batch Management System enables any defined control buttons in the control system. The control system interprets the control button request and performs the appropriate function.

You can use this section in Automatic, Semi-Automatic, and Manual phases; however, it is optional and depends on the function of the phase.

Interlocks

The interlock section of the phase block defines only the specific interlock conditions associated with that phase block. Each interlock condition is assigned to a discrete memory point and to a tag in the batch control system.

This section appears only if specific interlocks are associated with the phase block.

Alarms

The alarm section handles all error conditions specifically associated with the phase block. All the alarms appropriate to the phase are placed in parallel with each other to engage a single discrete point that is used through the remainder of the phase logic to affect the operation of the block.

This section appears only if alarms are associated with the phase block.

Phase Status

The phase status section includes the logic necessary to place the phase block into any one of the following modes: Ready, Run, Held, Done, Interlocked, and Aborted. Only one of these modes can be enabled at any time. When all of the status control logic has been evaluated, the results are transferred to the phase block status word that is monitored by AVEVA Batch Management System.

You must include this section for every Automatic and Semi-Automatic phase block.

Functional Logic

The remainder of the phase block writes the logic that performs the required process or transfer action. This section varies in size and complexity depending on the phase block operation and contains the computational, comparison, and timing functions required by the phase block.

This section also includes code that is associated with any formula parameters that may be assigned to the phase block, as well as logic necessary to energize process outputs.