粗略看了下，SERCOS是一款运动控制总线，多用于多轴同步应用，主要控制对象为驱动器、控制器，I/O和PLC，支持I/O通讯；它无法与传送传感器信息、电机启动器、启停变频器或者传送异步信息的现场总线相竞争。

SERCOS因为其置于驱动器中的使能轴、插补、register等轴控功能使得其适用于分布式控制，因此，运动控制器能专注于运动控制。在运行中，控制器根据先前的参数值，进行闭环控制和插补计算，发送位置值给驱动器。SERCOS总线也集成了极限开关、按钮和传感器。

SERCOS总线在一个伺服系统中计算所有轴的位置值，并同步发送给所有轴。

SERCOS I 使用ASIC，通讯速率2 and 4 Mbit/sec，SERCOS II使用ASIC，通讯速率2/4/8/16 Mbit/sec，向下兼容SERCOS I，SERCOS I 和II 采用主从模式的光纤环网，可以有多个环，每个环最大为254台设备。

SERCOS-III为工业以太网通讯，采用一对双绞线，同样也支持光纤通讯。

The SERCOS interface allows drive and control manufacturers to create intelligent digital drives with vastly improved capabilities and flexibility. A single drive can be designed to handle multiple motors, such as permanent magnet servomotors, high horsepower induction servomotors (vector drives) and linear motors, with the configuration set-up parametrically.

Types of products used on SERCOS include:

 AC and DC servo positioning drives 
 Spindle and main drives 
 Stepper indexer/drives 
 Vector drives 
 Linear motor drives 
 Inverters/variable frequency drives 
 Multi-axis motion controllers 
 I/O modules 
 PLC interfaces 
 Numerical controls 
 Electrohydraulic valves and positioning systems 

The SERCOS interface provides the flexibility of configuring multi-vendor control systems with plug and play interoperability. Designers are not limited to products from one manufacturer, but are free to choose the best-in-breed to solve their individual motion and I/O control problems.

The SERCOS interface reduces system cost, eliminates many types of noise problems and helps machine designers get motion control systems up and running quickly.

Even more importantly, the SERCOS interface has facilitated great advances in machine productivity. End users have realized incredible timesaving advantages with SERCOS on their machines -- faster delivery, faster installation, faster setup, faster product changeover, and faster production speeds.

 
The SERCOS interface is a foundation for building distributed multi-axis control systems for a myriad of applications. Distributed control improves machine flexibility by moving processing power and decision making from the CNC or motion control down into the drives and sensors. These devices then become intelligent building blocks that can easily be added to a machine or production line without major changes in hardware and software.

The SERCOS interface is well suited for distributed control because it places axis-dependent control functions, such as loop closures, interpolation, and registration, in the drives, not in the motion controller. Thus, motion controllers can concentrate on motion control profiles and tool paths independent of the axes. In operation, the control issues a position command to the drive, which then closes its own loops and micro-interpolates its trajectory, based on previously downloaded parameters. The SERCOS interface also integrates input/output functions such as limit switches, pushbuttons and various sensors.