C#与三菱FX2NPLC的RS232接口通讯(Write)

Write的逻辑与上文Read设置相同，如有不清楚的请看上文C#与三菱FX2NPLC的RS232接口通讯(Read),本文用于说明Write的功能

1. Write数据命令格式

02H 31H 起始地址 写入长度N 数据1.....数据N 03H 校验1 校验2

02H 代表命令开始

31H 代表写入命令

03H代表命令结束

起始地址计算方法:

 

 ex: 读D123,D124两个点的数据

D123对应地址计算方法为：

123*2=246

246对应十六进制为F6H

Address=F6H+1000H=10F6H

故实际地址未 31H 30H 46H 36H

加入需要读取D123，D124两个地址,因为D的长度为2,所以读取长度应该为2*2=4

故长度为 30H 34H

校验计算方法为:

02H后到03H为止(包含03H)相加,然后取最后两位得到校验数据

如02H 31H 31H 30H 46H 36H 30H 34H 数据1 数据2 03H 校验1 校验2

命令每个数据由4个字节组成，格式为L1L2H1H2

假设数据1为124(D)数据2为35(D)

数据1 124(D)=7C(H)=007C(C)

命令为 37H 43H 30H 30H

数据2 35(D)=23(H)=0023(H)

命令为32H 33H 30H 30H

故实际命令如下

02H 31H 31H 30H 46H 36H 30H 34H 37H 43H 30H 30H 32H 33H 30H 30H 03H 校验1 校验2

校验位=

31H+31H+30H+46H+36H+30H+34H+37H+43H+30H+30H+32H+33H+30H+30H+03H=314H

校验1=31H 校验2=34H

最终命令

02H 31H 31H 30H 46H 36H 30H 34H 30H 30H 37H 43H 30H 30H 32H 33H 03H 31H 34H

写入成功后收到如下回复

 

查看实际数据

 

正确写入

C#代码为(配置等信息,请看上文Read部分,本文只展示写入数据部分源代码)

 string[] datas = txtWriteData.Text.Split(',');

            int length = Convert.ToInt32(txtLength.Text);

            if (datas.Length < length)

            {

                MessageBox.Show("写入数据长度与操作长度不匹配,请重新操作");

                return;

            }

            int[] wdatas = datas.Select(t => Convert.ToInt32(t)).ToArray();

            byte[] buffers = new byte[length * 4 + 11];

            buffers[0] = 0x02;

            buffers[1] = 0x31;//30读,31写

            if (txtStartAddress.Text.StartsWith("D"))

            {

                int addSou = Convert.ToInt32(txtStartAddress.Text.Substring(1));

                if (addSou > 9999 || addSou < 0)

                {

                    MessageBox.Show("地址范围为0-9999");

                    return;

                }

                addSou *= 2;

                int addBase = 4096;//1000H对应10进制为4096

                int startAdd = addBase + addSou;

                string strAdd = startAdd.ToString("x8").TrimStart('0').ToUpper().PadLeft(4, '0');

                buffers[2] = Convert.ToByte(strAdd[0]);

                buffers[3] = Convert.ToByte(strAdd[1]);

                buffers[4] = Convert.ToByte(strAdd[2]);

                buffers[5] = Convert.ToByte(strAdd[3]);

            }

            string strLen = (length * 2).ToString("x8").TrimStart('0').ToUpper().PadLeft(2, '0');

            buffers[6] = Convert.ToByte(strLen[0]);

            buffers[7] = Convert.ToByte(strLen[1]);

            for (int i = 0; i < length; i++)

            {

                string temp = wdatas[i].ToString("x8").TrimStart('0').ToUpper().PadLeft(4, '0');

                //写入数据的顺序是34,12

                buffers[i * 4 + 8] = Convert.ToByte(temp[2]);

                buffers[i * 4 + 9] = Convert.ToByte(temp[3]);

                buffers[i * 4 + 10] = Convert.ToByte(temp[0]);

                buffers[i * 4 + 11] = Convert.ToByte(temp[1]);

            }

            buffers[buffers.Length - 3] = 0x03;

            int total = 0;

            for (int i = 1; i < buffers.Length - 2; i++)

            {

                total += Convert.ToInt32(buffers[i].ToString());

            }

            string cal = total.ToString("x8").TrimStart('0').ToUpper();

            cal = cal.Substring(cal.Length - 2).PadLeft(2, '0');

            buffers[buffers.Length - 2] = Convert.ToByte(cal[0]);

            buffers[buffers.Length - 1] = Convert.ToByte(cal[1]);

            sp.Write(buffers, 0, buffers.Length);

            MessageBox.Show("写入成功!");

以上为使用RS232协议C#读写三菱FX2NPLC的全部设置，如有不清楚的地方，可以添加QQ1319666784交流学习