| 摘要 |
The present invention relates to air-conditioning control, more particularly to a ventilation system well suited for industrial applications, such as for air freshening of intensive livestock farms. The ventilation system comprises a master controller connected by communication links to slave controllers that regulate the operation of individual fan units. The master controller transmits to the slave controllers temperature or rotational speed set points calculated to maintain within the premises desired environmental conditions. The slave controllers enforce the set point (either temperature or rotational speed) by varying the magnitude of the voltage impressed across the excitation winding of the electric motor that drives the fan. At least one slave controller is provided with a temperature sensor allowing the slave controller to modulate the speed of the fan according to the local temperature. This feature is useful in situations when the master controller is no longer capable of sending valid set point data to the slave controller, either due to a malfunction of the master controller or because the communication link is interrupted. The local temperature sensor can also be used as backup to the main temperature sensor of the master controller. Should the main temperature sensor fail, the master controller reads the temperature remotely, over the communication link and this data is used to continue generating set points data that is transmitted to the slave controllers.
|
