| 摘要 |
PURPOSE: A protection circuit for a relay of a plc board is provided to reduce costs for replacing frequent PLC board while increasing a processing effect. CONSTITUTION: A relay protection circuit of a correction facility for a control PLC board includes a relay(40), a PLC board(1), and an auxiliary relay(50). The relay operates a solenoid valve(30) to run a correction facility for the rolled product. The PLC board comprises a control unit(2) turning on the relay. The auxiliary relay is connected in parallel to the relay of the PLC board.
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