nestjs S71200 连接 单个地址读写 多个地址读写 断连重连

要在nestjs中实现与S7-1200通信，可以使用node-snap7库。这个库是Snap7库的Node.js绑定，支持与S7-1200通信。

下面是如何使用node-snap7库在nestjs中实现连接、读取和写入单个地址的值：

1.安装node-snap7库

npm install node-snap7

2.在nestjs中创建一个service，并引入node-snap7库：

import { Injectable } from '@nestjs/common';
import * as snap7 from 'node-snap7';

@Injectable()
export class Snap7Service {
  private client: snap7.S7Client;

  constructor() {
    this.client = new snap7.S7Client();
  }

  connect(ip: string, rack: number, slot: number) {
    return new Promise((resolve, reject) => {
      this.client.connectTo(ip, rack, slot, (err) => {
        if (err) {
          reject(err);
        } else {
          resolve();
        }
      });
    });
  }

  readBool(db: number, byte: number, bit: number) {
    return new Promise((resolve, reject) => {
      this.client.readArea(snap7.S7AreaDB, db, byte, 1, snap7.S7Word, (err, data) => {
        if (err) {
          reject(err);
        } else {
          const value = (data[0] & (1 << bit)) !== 0;
          resolve(value);
        }
      });
    });
  }

  writeBool(db: number, byte: number, bit: number, value: boolean) {
    return new Promise((resolve, reject) => {
      const buffer = Buffer.alloc(2);
      buffer.writeInt16BE(value ? (1 << bit) : 0);
      this.client.writeArea(snap7.S7AreaDB, db, byte, buffer.length, snap7.S7Word, buffer, (err) => {
        if (err) {
          reject(err);
        } else {
          resolve();
        }
      });
    });
  }
}

3.在nestjs的controller中使用Snap7Service：

import { Controller, Get, Param } from '@nestjs/common';
import { Snap7Service } from './snap7.service';

@Controller('snap7')
export class Snap7Controller {
  constructor(private readonly snap7Service: Snap7Service) {}

  @Get('connect/:ip/:rack/:slot')
  connect(@Param('ip') ip: string, @Param('rack') rack: number, @Param('slot') slot: number) {
    return this.snap7Service.connect(ip, rack, slot);
  }

  @Get('readBool/:db/:byte/:bit')
  async readBool(@Param('db') db: number, @Param('byte') byte: number, @Param('bit') bit: number) {
    const value = await this.snap7Service.readBool(db, byte, bit);
    return { value };
  }

  @Get('writeBool/:db/:byte/:bit/:value')
  async writeBool(@Param('db') db: number, @Param('byte') byte: number, @Param('bit') bit: number, @Param('value') value: boolean) {
    await this.snap7Service.writeBool(db, byte, bit, value);
    return { success: true };
  }
}

4.在nestjs中使用Snap7Controller来连接、读取和写入单个地址的值：

http://localhost:3000/snap7/connect/192.168.1.100/0/1
http://localhost:3000/snap7/readBool/1/0/0
http://localhost:3000/snap7/writeBool/1/0/0/true

5.在nestjs中读取多个地址的值，可以使用readMultiVars方法：

import { Injectable } from '@nestjs/common';
import * as snap7 from 'node-snap7';

@Injectable()
export class Snap7Service {
  private client: snap7.S7Client;

  constructor() {
    this.client = new snap7.S7Client();
  }

  connect(ip: string, rack: number, slot: number) {
    return new Promise((resolve, reject) => {
      this.client.connectTo(ip, rack, slot, (err) => {
        if (err) {
          reject(err);
        } else {
          resolve();
        }
      });
    });
  }

  readMultiVars(vars: { area: number, dbNumber: number, start: number, amount: number, wordLen: number }[]) {
    return new Promise((resolve, reject) => {
      const items = vars.map((v) => {
        return {
          Area: v.area,
          DBNumber: v.dbNumber,
          Start: v.start,
          Amount: v.amount,
          WordLen: v.wordLen,
        };
      });
      this.client.readMultiVars(items, (err, data) => {
        if (err) {
          reject(err);
        } else {
          const values = data.map((d) => {
            if (d.WordLen === snap7.S7WLBit) {
              return (d.Value[0] & (1 << d.BOffset)) !== 0;
            } else {
              return d.Value;
            }
          });
          resolve(values);
        }
      });
    });
  }
}

6.在nestjs中使用Snap7Controller来读取多个地址的值：

import { Controller, Get } from '@nestjs/common';
import { Snap7Service } from './snap7.service';

@Controller('snap7')
export class Snap7Controller {
  constructor(private readonly snap7Service: Snap7Service) {}

  @Get('readMultiVars')
  async readMultiVars() {
    const vars = [
      { area: snap7.S7AreaDB, dbNumber: 1, start: 0, amount: 1, wordLen: snap7.S7Word },
      { area: snap7.S7AreaDB, dbNumber: 1, start: 2, amount: 2, wordLen: snap7.S7DWord },
      { area: snap7.S7AreaMK, dbNumber: 0, start: 0, amount: 1, wordLen: snap7.S7WLBit },
    ];
    const values = await this.snap7Service.readMultiVars(vars);
    return { values };
  }
}

7.在nestjs中实现断连重连，可以在Snap7Service中添加一个reconnect方法：

import { Injectable } from '@nestjs/common';
import * as snap7 from 'node-snap7';

@Injectable()
export class Snap7Service {
  private client: snap7.S7Client;

  constructor() {
    this.client = new snap7.S7Client();
  }

  connect(ip: string, rack: number, slot: number) {
    return new Promise((resolve, reject) => {
      this.client.connectTo(ip, rack, slot, (err) => {
        if (err) {
          reject(err);
        } else {
          resolve();
        }
      });
    });
  }

  readBool(db: number, byte: number, bit: number) {
    return new Promise((resolve, reject) => {
      this.client.readArea(snap7.S7AreaDB, db, byte, 1, snap7.S7Word, (err, data) => {
        if (err) {
          reject(err);
        } else {
          const value = (data[0] & (1 << bit)) !== 0;
          resolve(value);
        }
      });
    });
  }

  writeBool(db: number, byte: number, bit: number, value: boolean) {
    return new Promise((resolve, reject) => {
      const buffer = Buffer.alloc(2);
      buffer.writeInt16BE(value ? (1 << bit) : 0);
      this.client.writeArea(snap7.S7AreaDB, db, byte, buffer.length, snap7.S7Word, buffer, (err) => {
        if (err) {
          reject(err);
        } else {
          resolve();
        }
      });
    });
  }

  async reconnect() {
    await this.client.disconnect();
    await this.client.connect();
  }
}

8.在nestjs中使用Snap7Controller来断连重连：

import { Controller, Get } from '@nestjs/common';
import { Snap7Service } from './snap7.service';

@Controller('snap7')
export class Snap7Controller {
  constructor(private readonly snap7Service: Snap7Service) {}

  @Get('reconnect')
  async reconnect() {
    await this.snap7Service.reconnect();
    return { success: true };
  }
}