Data Structure

Depending on which level of zone management is applied, zone data, group data or system data will be used for saving the status and settings of control.

Zone Data structure is essential structure which contain all information for a zone. It is highly recommended to save zone data as retain variable for power safe. It has five sub structures:

• Internal status: status which is used internally in the function block, e.g. control state, group and zone index
• Machine status: machine specific status, e.g. PID parameters calculated from AutoTune.
• Process status: process specific status, e.g. actual temperature, status word, error word, duty cycle.
• Machine set values: machine specific set values, e.g. PID parameters, HighHigh and LowLow temperature limits
• Process set values: process specific values, e.g. control word, set point, High and Low limits.
• All status can only be read whereas all set values can be read and written by the user.

For group level, there is group data which contains the status of the group (e.g. control state of the whole group) and the control value of the group (e.g. enable / disable process of the zones in the group).

For system level, there is system data which contains the status of the system (e.g. control state of the whole system) and the control value of the system (e.g. enable / disable process of the zones in the system).