INPUT FILTERING
In order to control an industrial system, a control unit (analog card, digital card, PLC, etc.) must be aware of the physical variables to be controlled. These physical variables (position, speed, current, etc.) are measured using sensors which usually generate an electrical signal which varies in proportion with the physical variable measured. In industrial applications, the electrical signals received from the sensors by the control unit may contain undesirable information which will overwrite the useful measurement signal and affect the quality of the control function(s) performed. The type and source of this interference can include:
The existence of interference is connected to the quality of the design and construction of the system. However, efforts to improve the technical features of an installation can reduce the level of such interference. It is therefore advisable to set up a function to process the sensor signals in order to reduce and even eliminate interference through the use of "filters". On the M2 tool, these filters are available on the digital and analog inputs.