当报警时间超出一定时间段时，同时再执行急停指令，此为二级动作。
d.打滑；信号发出后，执行打滑声光报警指令, 再执行急停指令。
e.超速：信号发出后，执行超速声光报警和急停指令。 f.断带：信号发出后，执行断带声光报警和急停指令。 g.纵撕：信号发出后，执行纵撕声光报警和急停指令。
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附录
翻译部分
英文原文
Design and Implementation of
PLC-Based Monitoring Control System for Induction Motor
Maria G. Ioannides, Senior Member, IEEE
Abstract—The implementation of a monitoring and control system for the induction motor based on programmable logic controller(PLC) technology is described. Also, the implementation of the with the
results obtained from tests on induction motor performance is provided. The PLC correlates the operational parameters to the speed requested by the user and monitors the system during normal operation and under trip conditions. Tests of the induction motor system driven by inverter and controlled by PLC prove a speed regulation as compared to a conventional V f control system. The efficiency of PLC control is increased at industrial control of electric drives.
Index
Terms—Computer-controlled
systems,
computerized
monitoring, electric drives, induction motors, motion control, programmable logic controllers (PLCs), variable-frequency drives, voltage control.
I. INTRODUCTION
Since technology for motion control of electric drives became available, the use of programmable logic controllers (PLCs) with power electronics in electric machines applications introduced in the manufacturing automation [1], [2].This use offers advantages such as lower voltage drop when turned on and the ability to control motors and other equipment with a virtually unity power factor [3]. Many factories use PLCs in automation processes to diminish production cost and to increase quality and reliability [4]–[9]. Other applications include machine tools with improved precision computerized numerical control (CNC) due to the use of PLCs [10].To obtain accurate industrial electric drive systems, it is necessary to use PLCs interfaced with power converters, personal computers, and other electric equipment [11]–[13]. Nevertheless, this makes the equipment more sophisticated, complex,