METHOD AND DEVICE FOR FOLLOWING UP WELD LINE

PURPOSE:To perform exact follow-up of a weld line with the exact reference value obtd. by detecting welding current of a number of times meeting welding conditions and making a reference value. CONSTITUTION:The welding current value detected in the process of oscillation is calculated and stored. The calculation of various quantities is accomplished with some times of oscillating period and the number of said times is determined by the welding current, the diameter of a welding wire, the kind of shielding gas and welding attitude and is stored in the form of a table into an ROM. The data set in the control panel of a welding device and the data relating to th welding attitude set by a robot R are taken in and are selected by collating with the talble. If it is judged that the calculation of the varuous qnantities for the purpose of making a reference value is accomplished by the selected number of times, the average value is calculated and is determined as a reference value and is stored. An execution mode is then started. When the execution mode is started, the various quantities for determining the controlled variable are calculated and are compared with the reference value obtd. in the sample value. If there is a deviation between the same, such deviation is determined as the controlled variable.