| 摘要 |
1. An apparatus for monitoring electric resistance welding operations, particularly electric resistance spot welding operations, by a detection of the changes of parameters, namely, current and/or voltage, in dependence on time, comprising detectors (11 to 14) for detecting the instantaneous values of the parameters and a microprocessor (15) which from the instantaneous values of the parameters, which instantaneous values have been converted by at least one A/D converter, derives the changes of said parameters in dependence on time and in dependence on the degree of agreement of said change with a desired value generates control signals for indicating and/or control means (29-34), characterized in that the microprocessor (15) is connected to a memory (27), which is adapted to store a multiplicity of individual data, each of which corresponds to an instantaneous voltage or current value and/or to an instantaneous resistance value derived from said two values during a desired progress of a welding operation, and during a welding operation the microprocessor (15) samples at a predetermined cycle frequency a multiplicity of instantaneous actual values via the A/D converter (21) from peak value-detectors (11 to 14) for the parameters, which detectors are resettable by the microprocessor, the microprocessor associates the actual value data with the stored data which corresponds to a desired progress of the welding operation and compares said actual and stored data in a comparator stage and in dependence on the degree of agreement generates the control signals for the indicating and/or control means (29 to 34). |
