电流输出型横河变送器的输出范围常用的有0~20mA及4~20mA两种,电流变送器输出小电流及大电流时,分别代表电流变送器所标定的小及大额定输出值。以0~100A的电流变送器为例,对于输出0~20mA的变送器0mA电流对应输入0A值,输出4~20mA的变送器4mA电流对应输入0A值,两类传感器的20mA电流都对应100A值。对于输出0~20mA的变送器,在电路设计上我们只需选择合适的降压电阻,在A/D转换器输入接口直接将电阻上的0-5V或0-10v电压转换为数字信号即可,电路调试及数据处理都比较简单。对于输出4~20mA的横河变送器,电路调试及数据处理上都比较麻烦。但这种变送器能够在变送器线路不通时,短路时或损坏时通过能否检测到正常范围内的电流(正常时小值也有4mA),来判断电路是否出现故障,变送器是否损坏,因此得到更为广泛普遍的使用。由于4~20mA变送器输出4mA时,在取样电阻上的电压不等于0,直接经模拟数字转换电路转换后的数字里也不为0,单片机无法直接利用,一般的处理方法是通过硬件电路将4mA在取样电阻上产生的电压降消除,,进行A/D转换。http://www.wuhandekema.com/武汉德科蒙过程控制有限公司027-88062221传真:027-88068180。LED">ABSolute;top:0;border:0;width:undefinedpx;height:undefinedpx;" frameborder="0" src="https://googleads.g.doubleclick.net/pagead/ads?client=ca-pub-6745515041074118&ouTPUt=html&adk=1812271804&adf=3279755396&plat=1%3A32776%2C2%3A32776%2C8%3A134217728%2C9%3A134250504%2C16%3A8388608%2C17%3A32%2C24%3A32%2C25%3A32%2C30%3A1081344%2C32%3A32&format=0x0&url=https%3A%2F%2Fwww.bizrobot.com%2Fcompany_bloginfo.php%3Fact%3D1&ea=0&flash=28.0.0&pra=5&wgl=1&dt=1623223511181&bpp=12&bdt=81&idt=168&shv=r20210607&cbv=%2Fr20190131&ptt=9&saldr=aa&cookie=ID%3Df208fc56032ec04a-222ab57211c400ce%3AT%3D1602655468%3ART%3D1602655468%3AS%3DALNI_MZ90KP_NdNDKAtfzA4A4RaK0MMehQ&nras=1&correlator=3772520790409&frm=23&ife=1&pv=2&ga_vid=1303892192.1623223511&ga_sid=1623223511&ga_hid=1061479357&ga_fc=0&nhd=1&u_tz=480&u_his=8&u_java=0&u_h=1080&u_w=1920&u_ah=1030&u_aw=1920&u_cd=24&u_nplug=11&u_nmime=26&adx=-12245933&ady=-12245933&biw=1259&bih=816&isw=730&ish=360&ifk=2699508910&scr_x=0&scr_y=0&eid=42530671%2C31060030&oid=3&pvsid=3607051062222185&pem=596&ref=https%3A%2F%2Fwww.bizrobot.com%2Fcompany_bloginfo.php%3Fadd_suc%3D1&eae=2&fc=1920&brdim=684%2C142%2C684%2C142%2C1920%2C0%2C1259%2C816%2C730%2C360&vis=1&rsz=%7C%7Cs%7C&abl=NS&fu=32772&bc=29&ifi=1&uci=1.zc3t79rie442&dtd=202" marginwidth="0" marginheight="0" vspace="0" hspace="0" allowtransparency="true" scrolling="no" allowfullscreen="true" data-google-container-id="1.zc3t79rie442" data-load-complete="true"> |