306 lines
12 KiB
Markdown
306 lines
12 KiB
Markdown
# 控 - 控制框架
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工业生产中控制逻辑的复杂程度千变万化，往往需要具体行业专业人员完成专门的设计，从而提高了行业的技术壁垒，严重阻碍了工业领域的自动化和智能化升级。
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XiUOS 应用程序框架中的“控”子框架从“控制需求”本身出发，同时面向专业用户和非专业用户，通过对“控制需求”本身和复杂的工业控制流程进行深入分析，通过软件定义的方式，提出以“控制元”为核心的“控”制流程。具体地，本设计通过解耦复杂的工业控制流程，将工业生产中的各种复制工业控制流程分解为各种类型的“控制元”命令，这些“控制元”的命令以软件API的形式交互给用户使用，从而屏蔽了以 PLC 为中心的各种控制器的巨大差异，形成了方便易用的接口，降低了专业的技术壁垒，加速了工业领域的智能化升级。
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## 1. XiUOS“控”制框架的关键数据结构定义和解析
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```c
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struct xs_PlcAbility {
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const char name[XS_NAME_MAX]; /* name of the PLC ability instance */
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enum xs_PlcCtlType type; /* type of control the plcable to excute, such as HSC or PID control */
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char address[XS_PLC_ADDRESS_MAX]; /* The address for this function in the PLC*/
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struct xs_PlcDevice *pdev; /* corresponding PLC device */
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struct XS_DOUBLE_LINKLIST_NODE link;/* link list node */
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};
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```
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name成员是一个可读的名字，用于唯一标识一个xs_PlcAbility结构。
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type成员表示该xs_PlcAbility可控制的类型，用一个枚举变量表示：
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```c
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enum xs_PlcCtlType {
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XS_PLC_CONTROL_TYPE_HSC = 0, /* high-speed counter */
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XS_PLC_CONTROL_TYPE_PID , /* proportional,integral,derivative */
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XS_PLC_CONTROL_TYPE_PHASING , /* phasing control*/
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/* ...... */
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XS_PLC_CONTROL_TYPE_END,
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};
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```
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由于 PLC 里控制指令执行都是向数据模块DB写数据,需要知道该函数功能对应的数据块地址，这个用address标识。pdev成员表示该xs_PlcAbility所属的xs_PlcDevice结构，其具体定义在下文给出。 最后，在系统中不同控制类型的xs_PlcAbility被分别组织成不同的双链表，如高速计数器xs_PlcAbility链表、PID控制xs_PlcAbility链表等，使用的链表节点即为link成员。
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```c
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struct xs_PlcDevice {
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const char name[XS_NAME_MAX]; /* name of the device */
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struct xs_PlcInfo info; /* PLC info, such as vendor name and model name */
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struct xs_PlcOps ops; /* filesystem-like APIs for data transferring */
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struct xs_PlcInterface interface; /* protocls used for transferring data from program to PLC */
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structXS_DOUBLE_LINKLIST_NODE link; /* link list node */
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};
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```
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name成员记录 PLC 设备在系统中的名字，用于唯一标识一个xs_PlcDevice结构。
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```c
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struct xs_PlcInfo {
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uint32_t ability;
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const char *vendor;
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const char *product_model;
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};
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```
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info成员记录 PLC 设备的一些属性信息，包括 PLC 的能力ability、厂家名vendor与型号product_model，其中ability用一个位图表示该 PLC 设备可以控制进行的操作：
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```c
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#define XS_PLC_ABILITY_HSC ((uint32_t)(1 << XS_CONTROL_TYPE_HSC))
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#define XS_PLC_ABILITY_PID ((uint32_t)(1 << XS_CONTROL_TYPE_PID))
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#define XS_PLC_ABILITY_Phasing ((uint32_t)(1 << XS_CONTROL_TYPE_PHASING))
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/* ...... */
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```
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ops成员包含统一的、类似文件系统的API，用于和 PLC 设备通信，进行实际的数据读写和对 PLC 设备实现控制功能。在使用一个 PLC 设备前后需要打开（open）/关闭（close）该 PLC，实际为建立和关闭连接；read、write分别用与从 PLC 接收数据与向 PLC 发送数据，ioctl用于向 PLC 设备发送控制指令：
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```c
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structxs_PlcOps {
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int (*open)(struct xs_PlcDevice *pdev);
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void (*close)(struct xs_PlcDevice*pdev);
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int (*read)(struct xs_PlcDevice*pdev, void *buf, size_tlen);
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int (*write)(struct xs_PlcDevice*pdev, constvoid *buf, size_tlen);
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int (*ioctl)(struct xs_PlcDevice*pdev, intcmd, void *arg);
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};
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```
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interface成员表示用于与 PLC 进行通信时所用到的协议：
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```c
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struct xs_PlcInterface {
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enum xs_plc_protocol protocol;
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enum xs_plc_transport transport;
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};
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```
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xs_plc_protocol和xs_plc_transport是两个枚举类型，标识 PLC 设备和自研的两种终端之间用到的通讯协议，其定义如下：
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```c
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enum xs_plc_protocol{
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AB_ETH = 0,
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ADS_AMS,
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BACnet_IP,
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DeltaV,
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DF1,
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EtherNet_IP,
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Firmata,
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KNXnet_IP,
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Modbus,
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OPC_UA,
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S7,
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Simulated,
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};
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enum xs_plc_transport{
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TCP = 0,
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UDP,
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Serial,
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Raw_Socket,
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PCAP_Replay,
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};
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```
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:::tip
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注意两者间有对应关系而不是随意组合，如S7(STEP 7)只能采用TCP协议，而Modbus支持tcp/serial/raw socket/pcap replay，可以定义一个函数检查类型：
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xs_PlcProtocolCheck(struct xs_PlcDevice*);
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:::
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最后，系统中所有注册过的 PLC 设备被组织成一个双链表，即link成员。
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## 2.XiUOS PLC 控制框架驱动开发
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以HSC高速计数器为例。控制框架针对每个具体的控制类型将xs_PlcAbility进行扩充，采用类似面向对象的手段添加其他必要成员，如：
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```c
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struct xs_PlcAbilityHsc {
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struct xs_PlcAbility parent;/* inherit from xs_PlcAbility*/
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uint32_t (*write)(struct xs_PlcAbilityHsc *abl, void* param);
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void (*read)(struct xs_PlcAbilityHsc *abl, void* param)
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};
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```
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实现xs_PlcOps中的数据通信API，具体实现细节取决于 PLC 型号，无法实现的API可以置为NULL：
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```c
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structxs_PlcOpshsc_example_ops = {
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.open = hsc_example_open;
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.close = hsc_example_close;
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.read = hsc_example_read;
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.write = hsc_example_write;
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.ioctl = hsc_example_ioctl;
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};
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```
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实现xs_PlcAbilityHsc中的write和read接口，该接口用于向 PLC 的HSC模块发送控制参数和读取返回参数。在实现过程中可以使用xs_PlcOps中的接口与 PLC 进行通信。
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其中param为一个void类型指针，由于要写入的命令参数和要读取的返回参数往往不止一个，可以根据不同的控制类型定义不同的数据读写结构体，最后使用结构体指针进行强制类型转换即可。例如对于HSC：
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定义数据写入结构体：
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```c
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struct hsc_write{
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char id[id_max]; /* id_max is to identify the max HSC ctrl instruction of HSC */
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int cmd; /* HSC control type */
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};
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```
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其中id用来标识HSC，cmd表示要发送的具体指令，具体的指令可以用一个枚举类型来表示：
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```c
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enum HscCmdSubType{
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EnHsc = 0, /* enable HSC */
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EnCapture, /* enable the function of capturing the inputs */
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EnSync, /* enable the function of synchronous inputs */
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EnHSCRESET,
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En_CTRL_UPTODOWN ,
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... ...
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};
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```
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同理，其他的类型
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```c
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enum PIDcmdSubType{
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ENHsc = 0,
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EN_XS_PLC_CONTROL_TYPE_PID_COMPACT,
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XS_PLC_CONTROL_TYPE_PID_3STEP , /* valve of motor-driven */
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... ...
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};
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enum PHASEcmdSubType{
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ENPhase = 0,
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XS_PLC_CONTROL_TYPE_PHASING_MC_HALT,
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XS_PLC_CONTROL_TYPE_PHASING_MC_HALT_MOVE_ABSOLUTE,
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... ...
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}
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```
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定义数据输出结构体：
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```c
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struct hsc_read{
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uint32_t value; /* the main value you want to get, depends on the cmd */
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bool done; /* indicate whether the SFB has been done */
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bool busy; /* indicate whether the function is busy */
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bool error; /* indicate whether there is error */
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};
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```
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value是指定返回的变量值，与结构体hsc_write发送的指令cmd类型有关，down/busy/error是一些状态指示位。
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如我们要使用write函数向 PLC 发送HSC类型的控制指令：
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```c
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struct hsc_write write_example;
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```
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struct xs_PlcAbilityHsc hsc_example进行必要的初始化后，用强制类型转换作为参数传递给write函数：
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```c
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hsc_example ->write(&hsc_example,(struct hsc_write*)&write_example);
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```
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最后，将 PLC 设备添加到 PLC 框架。分别填充xs_PlcDevice与对应物理量的xs_PlcAbility结构（高速计数器即为xs_PlcAbilityHsc)，并依次使用xs_PlcDeviceRegister和xs_PlcAbilityRegister函数将其注册到 PLC 框架：
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```c
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int xs_PlcDeviceRegister (struct xs_PlcDeviceRegister *pdev);
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int xs_PlcAbilityRegister (struct xs_PlcAbilityRegister *abl);
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extern struct xs_PlcOps plc_example_ops;
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extern uint32_t plc_example_write(struct xs_PlcAbilityHsc *abl, void *param);
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extern void plc_example_read(struct xs_PlcAbilityHsc *abl, void *param);
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/* declare xs_PlcDevice and xs_PlcAbilityHsc objects */
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struct xs_PlcDevice hsc_example_pdev;
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struct xs_PlcAbilityHsc hsc_example_abl;
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void register_example_plc()
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{
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/* initialize and register the xs_PlcDevice object */
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memset(&hsc_example_pdev, 0, sizeof(xs_PlcDevice));
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hsc_example_pdev.name = "plc1";
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hsc_example_pdev.info.ability |= XS_PLC_ABILITY_HSC;
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hsc_example_pdev.info.vendor = "Siemens";
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hsc_example_pdev.info.product_model = "yyy";
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hsc_example_pdev.ops = &hsc_example_ops;
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hsc_example_pdev.interface.xs_plc_protocol = S7;
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hsc_example_pdev.interface.xs_plc_transport = TCP;
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xs_PlcDeviceRegister(&hsc_example_pdev);
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/* initialize and register the xs_PlcAbility of hsc object */
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memset(&hsc_example_abl, 0, sizeof(xs_PlcAbilityHsc));
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hsc_example_abl.parent.name = "hsc_1";
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hsc_example_abl.parent.type = XS_PLC_TYPE_HSC;
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hsc_example_abl.parent.pdev = &hsc_example_pdev;
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hsc_example_abl.read = hsc_example_read;
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hsc_example_abl.write = hsc_example_write;
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xs_PlcAbilityRegister((struct xs_PlcAbility *)&hsc_example_abl);
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/* initialize and register otherxs_PlcAbilityobject */
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memset(&other_example_abl, 0, sizeof(xs_PlcAbilityOther));
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... ...
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}
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```
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## 3. XiUOS PLC 控制框架的使用示例
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PLC 控制应用开发者使用 PLC 控制框架提供的API操作 PLC，PLC 的API可以分为通用API与控制类型特有API。通用API用于 PLC 的获取、打开与关闭，控制类型特有API用于不同种类 PLC 的不同控制指令。以具有HSC高速计时器功能的 PLC 为例：
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```c
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/* generic API: find a plcability instance by its name */
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struct xs_PlcAbility *xs_PlcAbilityFind(const char *name);
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/* generic API: open/close a plc ability instance */
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int xs_PlcAbilityOpen(struct xs_PlcAbility *abl);
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void xs_PlcAbilityClose(struct xs_PlcAbility *abl);
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/* HSC API: send control parameter to PLC and read HSC condition*/
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uint32_t xs_PlcHscWrite(struct xs_PlcAbilityHsc *abl, void *param);
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void xs_PlcHscRead(struct xs_PlcAbilityHsc *abl, void *param);
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```
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在发送命令和获取数据前，需要先获取并打开要使用的 PLC；PLC 打开后可以随时对 PLC 发送指令和对其数据进行读取；使用完毕后，须关闭 PLC。完整的使用过程示例如下：
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```c
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int main(int argc, char *argv[])
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{
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int ret;
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structxs_PlcAbility *abl;
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structxs_PlcAbilityHsc *hsc_abl;
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/* get the Plc hsc ability instance */
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abl = xs_PlcAbilityFind("hsc_1");
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XS_ASSERT(abl->type == XS_PLC_CONTROL_TYPE_HSC);
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/* open the Plc hscability instance */
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hsc_abl = (struct xs_PlcAbilityHsc*)abl;
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ret = xs_PlcAbilityOpen(abl);
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XS_ASSERT(ret == XS_EOK);
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/* initialize the write and read data structure */
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structhsc_write write1={
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.id = "xxx";
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.cmd = EnHsc;
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};
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struct hsc_read read1;
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/* send control param to the HSC, just for demonstration */
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xs_PlcHscWrite(hsc_abl,write1);
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/* read data from hsc, just for demonstration */
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xs_PlcHscRead(hsc_abl,read1);
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if(!read1.error)
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xs_kprintf("Read data from PLC HSC is \n", read1.value);
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else
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xs_kprintf("Read data from PLC HSC wrong!\n")
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xs_PlcAbilityClose(abl);
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return 0;
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}
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```
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