PFEA113-65控制器,PFEA113-65配置手册
PFEA113的Profibus DP通信3.13.1关于Profibus-DP的一般数据PFEA113中Profibus DP通信的目的是提供高速上级系统和PFEA113之间的通信链路。Profibus-DP是一种多点通信协议，旨在将PLC连接到传感器（DP指“分布式外围设备”）。物理接口为RS 485（双线电缆）。最大传输速率为12 Mbit/s。该协议基于主从原则。PFEA113是从机。
PFEA113-65控制器现场总线主机一直轮询从机，这意味着轮询以固定的时间间隔进行当PFEA113没有新数据可用时。每个从机的地址范围为0到125。Profibus需要消息格式、通信参数和错误代码在所谓的类型文件（也称为GSD文件）中提供了从文件的个数（见附录a.8）Profibus DP-PFEA113的GSD文件）。该文件随后存储在Profibus主机中。启动时，Profibus主设备验证具有给定类型文件的从设备确实可用在公共汽车上。3.13.2主从通信主设备和从设备通过输出缓冲器和输入缓冲器进行通信。主机读取输入缓冲区，并在每个扫描周期向输出缓冲区写入一次现场总线。从机轮询输出缓冲区并更新输入缓冲区中的值。短线路高达1500 kbit/s<6.6 m。如果您使用的是12 Mbits/s，则应避免使用短截线。如果使用EN 50 170规定的线路A，总线端接电阻组合如图3-23所示，以确保线路上有定义的空闲状态电势。EN 50170中规定总线为A型线。应避免使用B型线。介质的物理性质如表3-3和表3-4所示。Profibus DP Communication with PFEA113
3.13.1 General Data about Profibus DP
The purpose of the Profibus DP communication in PFEA113 is to provide a high speed
communication link between superior systems and the PFEA113.
Profibus DP is a multidrop communication protocol intended to connect PLCs to sensors (DP
means “Distributed Peripherals”).
The physical interface is RS 485 (two wire cable).
The maximum transfer rate is 12 Mbit/s.
The protocol is based on a master-slave principle. The PFEA113 is a slave. A Profibus master
polls the slaves all the time, that means the polling is going on with a fixed time interval even
when no new data is available from the PFEA113.
Each slave has an address in the range 0 to 125.
Profibus requires that the message format, communication parameters and error codes
of slaves are made available in a so called type file, also known as GSD file (See Appendix A.8
Profibus DP - GSD File for PFEA113). This file is then stored in the Profibus Master.
At start-up the Profibus Master verifies that the Slave with the given type file is indeed available
on the bus.
3.13.2 Master-slave Communication
The Master and the slave communicate via an output buffer and an input buffer.
The master reads the input buffer and writes to the output buffer once every scan cycle for
Profibus.
The slave polls the output buffer and updates values in the input buffer.Stub lines up to 1500 kbit/s < 6.6 m.
If you are using 12 Mbits/s you should avoid stub lines.
If you are using line A as specified by EN 50 170, the bus terminating resistance combination
is as shown in Figure 3-23, so that a defined idle state potential is ensured on the line.
The bus line is specified in EN 50170 as line type A. Line type B should be avoided.
The physical properties of the media are shown in Table 3-3 and Table 3-4.
