Automatic round trip control circuit

.If the equipment needs to automatically run back and forth within the set stroke, the automatic back-and-forth control
circuit as shown in Figure 3-26 can be used. Automatic reciprocating control circuits are widely used in machine tool control circuits such as milling machines, grinders, lathes, hammering machines , etc.
Stoppers 1 and 2 are installed on the workbench , and the machine tool bed is equipped with travel switches SQi, SQ2, SQ3, and SQ4. Among them, s03 and SQ4 are used as
limit protection. When SQi or SQ2 fails, SQ3 and SQ4 can enable The workbench comes to a stop (at the extreme position). Due to the function of SQi and SQ2, the motor can be automatically switched forward and reverse, so that the workbench can automatically move back and forth
within the range of SQi and SQz .