SQA_ChillerSeq
The sequencer macro “SQA_ChillerSeq” is a general-purpose module. It can be used to sequence up to 3 loads. In combination with the sequencer add-on module „SQB_ChillerSeqAddOn“, the number of outputs can be extended up to 12 loads. The loads can be chillers, pumps, fans, or even complete cooling towers. The sequence order can be changed based on one of the following conditions:
- time rotation
- load rotation (first ON first OFF)
- run-time rotation
Along with the sequencer add-on macro „SQB_ChillerSeqAddOn“ up to 12 loads can be sequenced. Display values provide information about the:
- next to start load
- next to stop load
- cumulated runtime of the loads
- actual sequence order of the loads

Fig. 1. Sequencing Loads
Features
- 4 rotation modes:
- No rotation
- fixed time rotation
- load rotation
- runtime rotation
- Operator sequence overwrite
- Adjustable delays for increasing and decreasing number of loads
- Failure change-over, with adjustable change-over delay time
- During rotation, loads can be overlapped or have a gap in between
- Load control input “Req_Loads” may be the type of:
- absolut: 0 to N quantity
- floating: + or - quantity
- modulating: percent signal
- Load status monitoring and alarming
- Multistage/enum outputs to control 2-stage fans or complete cooling towers