1、第 26卷第 5期2009年 5月null nullnull nullnull nullM echan ical 使用平滑电路以提高所输出的模拟量信号的线性度,使其具有输出一定范围的模拟量的功能, 并拓展了 PLC晶体管开关量输出的功能b研究结果表明, 该方法的使用大大降低了设备成本的投入, 可应用于对模拟量信号分辨率及精度要求不高的场合,具有一定的实用价值b1oM:可编程逻辑控制器;开关量输出; 模拟量输出; PWM脉宽调制;占空比; RC时间常数ms |: TP273null null null nullDS M : BcI|: 1001- 4551( 2009) 05- 0105- 03
2、M e thod of achieving analog value output based on PLC digital outputWANG Zh-im ing(HangzhouEngineCo., Ltd., ChinaNationalHeavyDutyTruck Group, Hangzhou 310015, China)Abstrac t: In order to rea lize the controlling of ana log va lue output by programm able log ic contro ller( PLC) w ith low cost, a
3、m eth-od of PLC dig ital value was put forw ard to rea lize the analog va lue output. U sing the pulse w idth m odu la tion ( PWM ) techno logy,PLC trans istor dig ita l ou tput signa lw as contro lled by contro lling the duty ratio o f the pu lse. By app ly ing smoo th c ircuit, the line-a rity of
4、the output analog signa lw as im pro red. T he functionality o f the PLC transistor d ig ita l output was w idened. The resea rchshow s that the me thod g rea tly reduces the equipm ent cost, and can be practica lly used in cases where ana logue va lue reso lutionand precision are no t h igh ly dem
5、anded.K ey words: programmable log ic contro ller( PLC); dig ita l output; ana logue output; pulse w idth modu lation( PWM ); duty ra tio;RC tim e constant0null 引null 言PLCX$B LC E ZE,+Y Bt “9N , Nb “0/ ?Z, PLC m4,PMW/ LC E , sO q#L |vl b ID( Re feren ces): 1 null . z( PWM )/ null$aC#Z J. ., 1996, 26
6、( 3) : 2- 12. 2 null 9 . o b1BZE J.S t, 1992, 12( 4) : 41- 44. 3 null M itsubish i Electric Co rporation. Fx1s, Fx1n, Fx2n, F x2ncI mM . +, 2001. 4 null null , null. SIMAT IC S7-200 CPU 22X“ PLC zV ( PWM ) P J . S, 2007, 4( 2): 206- 216. 5 null S iem ens. S7-200 VI e “d m M . S iem ens,2004. 6 nullf pa, +k. PLC e J./ , 2008, 37( 1) : 104- 106. 7 null S iem ens. SIM AT IC P rogramm ing w ith STEP7 V5. 3 M anua l M . S iem ens, 2004. I : nullnull107null5 : PLC 71 LC E ZE
