The S0 interfaces are in the classes A and B divided.
Class A is for long transmission paths and a voltage of up to 27 V DC defined. Class B is for short transmission paths and a voltage of up to 15 V DC defined. The counter pulse must be at least 30ms long.
At the binary inputs BE/S and the universal interface US/U there are limits, they have to be observed indispensable!
Must not undercut the minimum counter pulse width of 50 ms.
A fast pulse sequence < 50 milliseconds is not recognized by the binary inputs or evaluated.
The frequency of maximum 5 Hz should not be exceeded also.
Please check the technical specifications for the S0 interface of the respective manufacturer.