@ali-pay/node-red-contrib-s7 v3.3.1

node-red-contrib-s7

A Node-RED node to interact with Siemens S7 PLCs.

This node was created as part of the ST-One project.

更新日志

v3.3.1

• s7-out 节点重构 失败重写 的逻辑

改前：写入数据->读取最新值->判断是否成功->等待间隔时间->重试写入数据
改后：写入数据->等待间隔时间->读取最新值->判断是否成功->重试写入数据

• s7-out 节点重构 async-await 的语法

v3.3.0

• s7-endpoint 节点增加 失败重写 的配置

  注意！
  应与PLC开发人员约定：如果要重置数据，则数据必须至少保留3秒再重置，避免写入数据后立即重置而导致程序认为写入数据失败

  失败重写次数：该参数大于0时，当写入数据失败后，会自动重试写入数据，直至达到该次数限制
  
  失败重写间隔：重试写入数据的时间间隔

• s7-in 节点重构 msg 的输出

  {
    // s7 节点参数
    "_s7": {
      "plc": "7#-8#",                       // plc 名称
      "ip": "172.19.21.70",                 // plc ip
      "status": "在线",                     // plc 状态 [在线/离线]
      "time": "2024-07-26T02:15:38.128Z"    // msg 消息时间
    },
  
    // msg 消息内容
    "payload": { "a":1, "b":2 }
  }

• s7-out 节点重构 msg 的输出

  {
    // s7 节点参数
    "_s7": {
      "plc": "7#-8#",                       // plc 名称
      "ip": "172.19.21.70",                 // plc ip
      "status": "在线",                     // plc 状态 [在线/离线]
      "time": "2024-07-26T02:15:38.128Z"    // msg 消息时间
    },
  
    // msg 消息内容
    "payload": {
      "variable": ["a", "b"],               // 写入的键 msg.variable
      "payload": [1, 2],                    // 写入的值 msg.payload
      "values": { "a":1, "b":2 },           // 写入的键值对
      "newValues": {},                      // plc的最新键值对
      "wrongValues": {},                    // 跟写入值不一致的键值对
      "bingo": false,                       // 是否写入成功 [plc的最新值跟写入值是否一致]
      "error": "Error: Not connected"       // 错误
    }
  }

• s7 所有节点增加 简体中文 的翻译

v3.2.0

• s7-in 节点增加 设备状态 的输出

  {
        "name": "7#-8#",       // plc 名称
        "ip": "172.19.21.70",  // plc ip
        "status": "online"     // plc 状态 online / offline
  }

• s7-out 节点增加 写入结果 的输出

  {
        "error": "Error: Not connected", // 错误
        "variable": ["a", "b"],          // 写入的键 msg.variable
        "payload": [1, 2],               // 写入的值 msg.payload
        "values": { "a":1, "b":2 },      // 写入的键值对
        "newValues": {},                 // plc的最新键值对
        "bingo": false,                  // plc的最新值跟写入值是否一致
        "wrongValues": {}                // 跟写入值不一致的键值对
  }

Install

You can install this node directly from the "Manage Palette" menu in the Node-RED interface.

Alternatively, run the following command in your Node-RED user directory - typically ~/.node-red on Linux or %HOMEPATH%\.nodered on Windows

    npm install node-red-contrib-s7

NodeJS version 10 or greater and Node-RED version 1.0 or greater is required.

Usage

Each connection to a PLC is represented by the S7 Endpoint configuration node. You can configure the PLC's Address, the variables available and their addresses, and the cycle time for reading the variables.

The S7 In node makes the variable's values available in a flow in three different modes:

• Single variable: A single variable can be selected from the configured variables, and a message is sent every cycle, or only when it changes if diff is checked. msg.payload contains the variable's value and msg.topic has the variable's name.
• All variables, one per message: Like the Single variable mode, but for all variables configured. If diff is checked, a message is sent everytime any variable changes. If diff is unchecked, one message is sent for every variable, in every cycle. Care must be taken about the number of messages per second in this mode.
• All variables: In this mode, msg.payload contains an object with all configured variables and their values. If diff is checked, a message is sent if at least one of the variables changes its value.

Variable addressing

The variables and their addresses configured on the S7 Endpoint follow a slightly different scheme than used on Step 7 or TIA Portal. Here are some examples that may guide you on addressing your variables:

• *) Note that strings on the PLC uses 2 extra bytes at start for size/length of the string
• **) Note that javascript's Date are always represented in UTC. Please use other nodes like node-red-contrib-moment to properly handle type conversions

Notes on S7-1200/1500

These newer PLCs offer an "extended" version of the S7 Protocol, while we have only a "basic" version of it.

Therefore, some additional configuration steps on the PLC are necessary:

• "Optimized block access" must be disabled for the DBs we want to access (image)
• In the "Protection" section of the CPU Properties, enable the "Permit access with PUT/GET" checkbox (image)

Notes on Logo! 8

On the newest Logo! 8.FS4 (and possibly 0BA8) Logic modules there is no need to set the Mode to TSAP any more, instead the default Rack/Slot value of 0/2 works just fine.

The following table shows memory areas accessible without additional settings in the controller program:

Note: These memory areas seem to be read-only from outside the controller, as they are directly used by the function blocks listed in "Logo Block" of the table

On the other hand, Logo memory areas VM 0-849 are mutable from outside the controller, but they need to be mapped into the Logo program. Without mapping, data written into these addresses will have no effect on program execution. Used VM addresses in the range mentioned above can be read/written from/into in the Logo program using the "Network" function blocks (in the function block setup use the "Local variable memory (VM)" option to map VMs to the function block).

Some addressing examples:

Bugs and enhancements

Please share your ideas and experiences on the Node-RED forum, or open an issue on the page of the project on GitHub

Support

Community support is offered on a best-effort basis via GitHub Issues. For commercial support, please contact us by sending an e-mail to st-one@st-one.io.

License

Copyright: (c) 2016-2022, ST-One Ltda., Guilherme Francescon Cittolin guilherme@st-one.io

GNU General Public License v3.0+ (see LICENSE or https://www.gnu.org/licenses/gpl-3.0.txt)