| 摘要 |
A real time remote sensing pressure control system is provided which uses periodically sampled remote sensors to generate a bias signal that modifies the base setpoint of a proportional-integral controller that controls variable speed pumps. This control scheme saves energy by slowing the rotational speed of the variable-speed secondary pumps during periods of light system demand. The system can be provided with more than one zone of system loads (such as chilled or hot water coils) and a remote pressure sensor (gauge or differential) can be provided at each of those zones. In addition, a local pressure sensor (gauge or differential) is provided at the primary and secondary pumps. The process variable signals detected by the remote pressure sensors is communicated by a building automation system or other type of data highway, which inherently delays the real time nature of those sensed signals and only periodically provides an update of those signals. To provide stable control of the variable speed pumps, the local pump controller utilizes the local pressure sensor's signal to control the speed of those pumps in a stable manner, and a bias signal is provided based upon the periodically updated remote signals from the remote pressure sensors of each zone. In a typical multi-zone control system, the zone requiring the greatest pressure change is selected and its signal is used to create the necessary bias signal that is used to control the variable speed pumps. This control scheme can be utilized in booster pressure systems or other pumping systems in which more than one pumping location must supply water or other liquids to remotely located and diverse loads. In an alternate embodiment, a real time remote sensing pressure control system is provided that utilizes more than one water and pumping source at remote locations from one another to supply a common distribution system. This distribution system can either be a non-recirculating system, such as a potable water system, or can be a recirculating system in which some or all of the liquid is to be returned to the source, such as in chemical plants or oil refineries.
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