Controller for cutting machine

Claim 1

A controller for a cutting machine comprising: a machining power extracting means for extracting a machining power related to a machining from consumed power of the cutting machine, said machining power extracting means comprises a cyclic noise removing circuit for removing cyclic noise components from the consumed power, a smoothing circuit for smoothing the output values of said cyclic noise removing circuit, a no-load power extracting circuit for extracting no-load power from the output values of said cyclic noise removing circuit and said smoothing circuit, and machining power computing circuits for subtracting the output of said no-load power extracting circuit from the output values of said cyclic noise removing circuit and said smoothing circuit; a detection range setting means, connected to said machine power extracting means, for setting a detection range for the machining power thus extracted; an integration means, connected to said machining power extracting unit, for integrating the output value of said machining power extracting means within the detection range thus set; a maximum value detecting means, connected to said machine power extracting means, for detecting the maximum value of the output values of said machining power extracting means within said detection range; and a judging means for comparing an input signal with a variable comparative reference value and producing a control signal if said input signal exceeds said comparative reference value, said judging means having an input which is selectively connectable to said machining power extracting means, integration means and maximum value detecting means.