摘要
PLC所使用的通讯协议一般而言实属大同小异,故文中所提及之基本通讯命令解说与实作,其它厂牌或机种之PLC亦可适用。此外目前多数的工业控制设备或装置,诸如:温度控制器、电子磅秤、变频器等大都支持Modus通讯协议,其数据格式包含:地址、命令码、数据与检查码(CRC-16)等,与PLC通讯协议大同小异,故本文将有助于读者对于PC、PLC与工控设备或装置间的通讯联机、讯息传输、数据交换及系统整合,有一基本的认知与了解。
Communication protocol of PLC in general is almost the same, so this article mentioned in basic communication command interpretation and implementation, other brands or models of PLC can also apply, in addition, most of the existing industrial control equipment or devices, such as temperature controller, electronic scales, inverter and other general support for Modus communication protocol, the data format includes： address, command code, data and checksum （CRC-16）, etc., it is similar with PLC communication protocol. So this article will help the readers have a basic awareness and understanding to the PC, online communication between PLC and industrial control equipments or devices, message transmission, data exchange and system integration.
关键词
PLC
通讯
VB
编程
PLC
Communications
VB
Programming
