circuit for operation, the monitoring and fault diagnosis of a single channel air conditioning

摘要

1. Circuit for a single-duct air-conditioning installation of a passenger compartment coach with at least one central air-conditioning device (L), covering the basic heat requirement, for the flow temperature of the heating medium and with a central control device (SLa) and discrete supplementary heaters (N1, N2 ... Nn) for individual setting of the compartment temperature in each compartment, which in each case is controlled as a function of a set value generator S1 ... Sn, provided in each compartment via one control device for each (SA1, SA2 ... SAn), the heater coil (HR) of the central air-conditioning device being cut in and out intermittently by switching means as a function of a command variable for the flow temperature formed in the central control device from the particular duty cycle of the supplementary heaters (N1, N2 ... Nn) of the compartments, characterised by the following features : a. A current transformer (I) in the supply line to the bus bar of the supplementary heaters (N1, N2 ... Nn), b. A multipole change-over switch (U) in the connecting lines between each control device (SA1, SA2, ... SAn) and the associated regulating devices (R1, R2, ... Rn) for the compartment temperature, c. A remotely actuated selector switch (W), the selectable switching contacts of which are in each case connected to one single-throw contact each of the change-over switch (U), in each case one supplementary heater being energisable in turn in cyclical sequence, d. A test pulse generator (P), which emits at certain time intervals pulses for the actuation of the change-over switch (U) and for one passage of the selector switch (W), and one terminal of which generator is connected to the root of the selector switch (W), e. A logic and evaluation element (V) with a comparison device, in which the current value measured in the current transformer (I) in each case is compared in cyclical sequence with a nominal current value of the supplementary heaters stored in the comparison device and, in the event of a noticeable deviation of the measured value from the nominal current value, an error signal is given, which comparison device is in connection with the current transformer (I) and the test pulse generator (P) as well as with the drive mechanism of the selector switch (W), f. One remotely actuated switch (SS1, SS2, ... SSn) each in the connecting line between the control devices (SA1, SA2, ... SAn) for the supplementary heaters and the central control device (SLa), which switches are opened when an error signal is announced in the comparison device.