Temperature regulating system for air conditioning or heating plants, preferably in railway vehicles

A temperature-regulating system for an air conditioning or heating plant which includes

• a programmable digital processing unit which includes at least one input and at least one output, and
• a value-measuring unit which includes at least one temperature sensor, a capacitor, a switching element, a switching means and a reference voltage-generating means, each temperature sensor being connected to a capacitor so as to charge the capacitor by a current proportional to the measured temperature, the switching element being connected to the output of the digital processing unit and to the capacitor so as to cause the capacitor to discharge at a rate determined by the digital processing unit, the switching means including an output connected to the input of the digital processing unit and two inputs, the capacitor being connected to one input of the switching means and the other input of switching means being connected to the reference voltage-generating means, the digital processing unit acting via the switching element to discharge the capacitor and also repeatedly checking the output of the switching means for a signal change, the number of such checks commencing from the beginning of measurement to a change in the signal representing digital values corresponding to the measured temperature, the switching means changing its output signal when the capacitor voltage reaches the reference voltage.