초록 ▼

A microprocessor based system monitors and controls a transport refrigeration system having a two speed compressor coupled to a condenser and an evaporator and further having two speed condenser and evaporator fans, a refrigerant modulating valve, and heater means to cool or heat a served space. A k

A microprocessor based system monitors and controls a transport refrigeration system having a two speed compressor coupled to a condenser and an evaporator and further having two speed condenser and evaporator fans, a refrigerant modulating valve, and heater means to cool or heat a served space. A keypad is provided for operator entry of the temperature setpoint and for display selections. Return air and discharge air temperature sensors provide signals to the microprocessor for temperature control. The microprocessor is programmed to sequence or control the compressor, the fans, the modulating valve and the heater means for temperature control in accordance with one of four stored algorithms. One of the temperature sensors is used for control, and if it is detected to have failed automatic switchover is made to use of the other temperature sensor for temperature control. Various input signals from the refrigeration system and from the microprocessor hardware are processed by the microprocessor to provide a data log and data for display and to detect system faults for fault history storage and for protective control action.

대표청구항 ▼

A control system for operating a transport refrigeration system having a motor driven compressor coupled to a condenser and an evaporator coil and further having heater means so as to cool or heat a served space, said system comprising: temperature sensing means for sensing temperature in the served

A control system for operating a transport refrigeration system having a motor driven compressor coupled to a condenser and an evaporator coil and further having heater means so as to cool or heat a served space, said system comprising: temperature sensing means for sensing temperature in the served space; a microprocessor for monitoring and controlling said transport refrigeration system; means for coupling said temperature sensing means to said microprocessor; means for generating and coupling to said microprocessor an operator selected space temperature setpoint; means for comparing said operator selected set point with the temperature sensed by said temperature sensing means to provide a difference error; operating controls for the compressor motor and the heater means to provide the cooling and heating needed for space temperature control; means for coupling said operating controls to said microprocessor; an algorithm which defines in accordance with a set of rules the operating states of said operating controls; sequence/control operating means for operating said microprocessor to sequence or control said operating controls in accordance with said algorithm to produce a level of heat transfer to or from the served space on the basis of a level of said difference error between the setpoint and sensed space temperatures; means for detecting a status of predetermined refrigerant system parameters, and for coupling corresponding digital and/or analog input status signals to said microprocessor; means for operating said microprocessor to generate a sequential list of coded system faults corresponding to said system parameters and internally generated parameters detected to be in a fault status; means for operating said microprocessor to trigger a shutdown of the refrigeration system when any fault included in a predetermined set of system faults is detected to have occurred; nonvolatile read/write memory means for storing predetermined data including system fault data in said sequential list; means for controlling the storage of the system fault data in said sequential list in said nonvolatile read/write memory means so that at least a predetermined number of latest system faults are stored; means for operating said microprocessor to display the codes of the system faults stored in said sequential list in response to an input command so that the involvement of specific system parameters in any fault history is made available for maintenance management purposes.