| 摘要 |
<p>A digital welder control system for controlling a portable gun welder of the type used in the automotive industry on an assembly line. An 8 bit microprocessor is the main control element of the system. The known cycle time of the microprocessor is used to generate a real time delay which in turn is used to generate a digital phase shift heat control. RAM locations in the microprocessor are used to store medium constants of the welding sequence which were previously stored, in prior art controls, in the position of tap switches or thumbwheel switches. The controller provides diagnostics for six common problems often encountered by welder control systems such as override timeout, half cycling, transformer temperature rises, a low water flow, a shorted SCR, and a change in the heat settings. The controller also provides a maintenance interval counter and compensator control having a four-step stepper. The stepper control is used to automatically increase the weld heat after a preset number of welds to compensate for electrode mushrooming. The controller also checks the setting of address and data thumbwheels to prevent incorrect entries into the welding sequence. The controller also permits entry of data only into RAM locations which are used in the normal sequence of the welder. The controller also utilizes serial communication between a sequence module used to program the microprocessor and the microprocessor to economize on the number of drivers and receivers required and to reduce the power requirements of the controller.</p> |
