vykonPro-RotationalLoadSequencer

RotationalLoadSequencer provides lead-lag control of from 2 to 10 BooleanWritables based upon a fixed sequence. The number of active loads is determined by the Schedule and Required Loads inputs.

RotationalLoadSequencer is available in the HVAC folder of the vykonPro palette

Setup of the object involves the following properties, as follows:

Properties

Actions

Operation

When the Schedule value changes from false to true, the RLS attempts to start the number of loads specified by the Required Loads value. When a load is started the RLS changes the applicable OutX (where X = A-J) to true and starts a timer using the Feedback Delay value. When the timer expires, the RLS evalutes whether the applicable OutX is true and the matching FeedbackX is true. If the FeedbackX is false the load is considered failed and the RLS attempts to start the next load in the rotation order. If the FeedbackX for a running load changes from true to false after the feedback timer period has expired, the RLS considers the load failed while running and attempts to start the next load in the rotation order.

When the RLS evaluates that a load has failed it sets the alarm status bit for the applicable OutX slot and changes the Load Failed to true. The failed load OutX slot value remains true even though additional loads may be started to compensate for the failed load. A failed load with OutX slot status alarm bit set is not considered to be running even though the physical piece of equipment might be running

If the RLS has started all available loads and the number of running loads (OutX true and status OK, and FeedbackX true) is less than the Required Loads, the Status is set to Fault and the Fault Cause is updated to indicate 'Not enough loads available to start the required number of loads.

When the Schedule value changes from true to false, the RLS stops all of the outputs (changes all OutX slots to false) and clears the alarm status bit from any previously failed loads. This allows the RLS component to attempt to use the previously failed loads when the Schedule changes from false to true subsequently.