Reivindicaciones

1. A system for acquiring digital data in synchronous sequential circuits controlled by a signal with period T, characterized by comprising the following elements: - a capturing module that reads input data with a period T; - a memory module that stores the input data read by the capturing module; - a controller module that requests input data readings from the memory module and receives the input data stored by the memory module corresponding to the period before the request of the reading; 2. The system according to claim 1, wherein the capturing module further comprises an activation circuit that disables the capturing module when it is not necessary to acquire input data. 3. The system according to claim 2, wherein the activation circuit comprises an optocoupled system in the reverse direction. 4. The system according to any of the preceding claims, wherein the memory module is a latch. 5. The system according to any of the preceding claims, which further comprises a synchronization module that generates the synchronization signal that controls the circuit and further generates an activation signal for the capturing module and a memory signal for the memory module. 6. The system according to any of the preceding claims, wherein the capturing module comprises a galvanically isolated circuit. 7. The system according to any of the preceding claims, wherein the elements comprise polarization currents equal to or greater than 10 mA. 8. The system according to any of the preceding claims, which further comprises a control board of an air-conditioning system. 9. A method for acquiring digital data in synchronous sequential circuits controlled by a synchronization signal with period T, characterized in that it comprises the steps of: a) receiving a first input data in the capturing module, in a first synchronization cycle; b) transmitting the first item of input data from the capturing module to a memory module; c) requesting from the memory module, in a second synchronization cycle, an input-data reading, by means of a controller module; d) providing the first item of data to the controller module from the memory module; e) receiving a second input data in the capturing module, in the second synchronization cycle; f) transmitting the second item of input data from the capturing module to the memory module; g) replacing the first stored item of data by the second item of data in the memory module. 10. The method according to claim 9, which further comprises enabling the capturing module to receive input data with a period T according to the synchronization signal. 11. The method according to any of the preceding claims 9-10, which further comprises enabling the capturing module when no reading is necessary. 12. The method according to any of the preceding claims 9-11, wherein the steps a) - g) are cyclically repeated according to a period T, such that in the memory module there is always an item of data available to be read by the controller module. 13. The method according to any of the preceding claims 9-12, wherein transmitting an item of data from the capturing module to the memory module comprises polarizing an optocoupler inserted in the capturing module when receiving an input signal and, subsequently, transmitting its state to a latch in the memory module. 14. The method according to any of the preceding claims 9-13, wherein receiving a first and a second item of input data in the capturing module further comprises previously transmitting an activation signal from the synchronization module to the capturing module. 15. The method according to any of the preceding claims 9-14, wherein transmitting data to the memory module further comprises previously receiving a memory signal in the memory module sent from the synchronization module.