PWM隔离转换模块在西门子1200PLC上的应用

Application of PWM Isolation Conversion Module in Siemens 1200PLC

西门子1200PLC在控制模拟量设备时,需要加装西门子模拟量输出模块,但西门子模拟量输出模块点位少、价格高,为了不使用西门子模拟量输出模块,就能实现模拟量输出功能,针对PWM隔离转换模块在西门子1200PLC上的应用进行了试验研究。通过研究发现,PWM模块使用便捷、价格低廉、运行稳定,并能有效保护PLC回路,配合PWM转换隔离模块的西门子1200PLC最多可输出四路4~20 mA模拟量信号。依据PWM原理,利用西门子1200晶体管型PLC自带的PWM功能,通过Q点端子输出不同的脉宽信号,信号通过PWM隔离转换模块转换成4~20 mA模拟量信号,转换后的4~20 mA信号在恒流量给定的工业控制、恒压供水工业控制以及简单的调速、调压等控制中得到了较好的应用,且价廉性优。

When Siemens 1200 PLC controls analog equipment, it is necessary to install Siemens analog output module. However, Siemens analog output module has fewer points and high price. In order to achieve analog output function without using Siemens analog output module, the application of PWM isolation conversion module on Siemens 1200 PLC is studied experimentally. Through the research, it is found that the PWM module is convenient to use, low cost, stable operation, and can effectively protect the PLC circuit. Siemens 1200 PLC with PWM conversion isolation module can output four channels of 4~20 mA analog signals at most. According to the principle of PWM, the PWM function of Siemens 1200 transistor PLC is used to output different pulse width signals through the Q-point terminal. The signal is converted into 4~20 mA analog signal through the PWM isolation conversion module. The converted 4~20 mA signal has been better applied in constant flow given industrial control, constant pressure water supply industrial control, simple speed regulation and voltage regulation control, and it is inexpensive.