IEC104规约的秘密之六----配置参数k，w

104通讯前需要配置通讯参数，一般有如下参数：
IP地址，端口号，k，w，t1，t2，t3，公共地址，遥控超时参数，104主规约还有一个t0参数。
本次只讲解k,w这两个参数。

要讲解k,w参数，首先把104通讯用的几种帧类型讲一下，104分成两层通讯，一层链路层，一层应用层。用于应用层的报文称为I帧，只用于链路层通讯的为U帧和S帧。

k,w两个是一个数值，与104的帧计数有着密切的关系，在104通讯时，内部有3个计数器，分别是发送的I帧计数，发送后已经被对方确认的I帧计数，收到的I帧计数，前两个计数器是本方的I帧计数，最后一个是对方的I帧计数。

w是通讯前就已经配置好的一个固定值，范围是1~32767，表示收到对方w帧后就必须给对方一个应答了，表示这些帧我已经收到了，如果不给对方应答，对方会认为自己发的这些帧没有收到，后续可以采用其他机制来让对方收到自己的数据。

k是通讯前就已经配置好的一个固定值，范围是1~32767，表示发送了k个I帧后若对方还没有确认，则需要停下来等待了。

这里的k和w和TCP/IP的滑动窗口类似，对于k，一旦未被对方的确认I帧个数到达k，则相当于发送窗口已满，则不能发送了。若对方此时确认了部分帧或全部帧，则相等于发送窗口有空了，又可以发送了。w是类似的意识。

对于k，w的建议值，一般是12和8，即k=12，w=8，这也是为了配合通讯使用的。双方的k,w要配置为一样。这种情况下，比如对方的w是8，而我方的k是12，则在正常情况下，我方还没有发到12帧时，对方已经到8帧了，就会给与确认。这样双方就能连续不断的发送数据不需要停顿。再数据量大的通讯中，可以适当调大k，w的值，比如k=60，w=40，这样可以减少确认的帧数，提高发送的效率。

帧计数是从0开始到32767的，顺序计数，注意帧计数到最大值时会有翻转的情况，即会从32767变成0，通讯双方如何配合恰当，可以不断通讯，否则就只有断开连接，重新开始一轮新的计数。

只有I帧和S帧中有帧计数，下面看几个例子报文：

    00 00 00 00 --> I帧报文(低字bit0=0,高字bit0=0) 发送序号:0 接收序号:0 (发:低字bit1~bit15,收:高字bit1~bit15)2024/10/04 14:33:30.938 <<-- 68 0E 00 00 02 00 64 01 06 00 01 00 00 00 00 1400 00 02 00 --> I帧报文(低字bit0=0,高字bit0=0) 发送序号:0 接收序号:1 (发:低字bit1~bit15,收:高字bit1~bit15)2024/10/04 14:33:30.969 -->> 68 0E 02 00 02 00 64 01 07 00 01 00 00 00 00 1402 00 02 00 --> I帧报文(低字bit0=0,高字bit0=0) 发送序号:1 接收序号:1 (发:低字bit1~bit15,收:高字bit1~bit15)2024/10/04 14:33:30.985 -->> 68 0F 04 00 02 00 01 82 14 00 01 00 02 00 00 00 0004 00 02 00 --> I帧报文(低字bit0=0,高字bit0=0) 发送序号:2 接收序号:1 (发:低字bit1~bit15,收:高字bit1~bit15)2024/10/04 14:33:31.000 -->> 68 8C 06 00 02 00 01 FF 14 00 01 00 05 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0006 00 02 00 --> I帧报文(低字bit0=0,高字bit0=0) 发送序号:3 接收序号:1 (发:低字bit1~bit15,收:高字bit1~bit15)2024/10/04 14:33:31.022 -->> 68 8C 08 00 02 00 01 FF 14 00 01 00 84 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0008 00 02 00 --> I帧报文(低字bit0=0,高字bit0=0) 发送序号:4 接收序号:1 (发:低字bit1~bit15,收:高字bit1~bit15)2024/10/04 14:33:31.038 -->> 68 8C 0A 00 02 00 01 FF 14 00 01 00 03 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 000A 00 02 00 --> I帧报文(低字bit0=0,高字bit0=0) 发送序号:5 接收序号:1 (发:低字bit1~bit15,收:高字bit1~bit15)2024/10/04 14:33:31.054 -->> 68 8C 0C 00 02 00 01 FF 14 00 01 00 82 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 000C 00 02 00 --> I帧报文(低字bit0=0,高字bit0=0) 发送序号:6 接收序号:1 (发:低字bit1~bit15,收:高字bit1~bit15)2024/10/04 14:33:31.069 -->> 68 8C 0E 00 02 00 01 FF 14 00 01 00 01 02 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 000E 00 02 00 --> I帧报文(低字bit0=0,高字bit0=0) 发送序号:7 接收序号:1 (发:低字bit1~bit15,收:高字bit1~bit15)2024/10/04 14:33:31.085 -->> 68 8C 10 00 02 00 01 FF 14 00 01 00 80 02 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0010 00 02 00 --> I帧报文(低字bit0=0,高字bit0=0) 发送序号:8 接收序号:1 (发:低字bit1~bit15,收:高字bit1~bit15)2024/10/04 14:33:31.101 -->> 68 8C 12 00 02 00 01 FF 14 00 01 00 FF 02 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0012 00 02 00 --> I帧报文(低字bit0=0,高字bit0=0) 发送序号:9 接收序号:1 (发:低字bit1~bit15,收:高字bit1~bit15)2024/10/04 14:33:31.123 -->> 68 81 14 00 02 00 01 F4 14 00 01 00 7E 03 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0014 00 02 00 --> I帧报文(低字bit0=0,高字bit0=0) 发送序号:10 接收序号:1 (发:低字bit1~bit15,收:高字bit1~bit15)2024/10/04 14:33:31.138 -->> 68 F8 16 00 02 00 0D AF 14 00 01 00 0A 40 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0016 00 02 00 --> I帧报文(低字bit0=0,高字bit0=0) 发送序号:11 接收序号:1 (发:低字bit1~bit15,收:高字bit1~bit15)2024/10/04 14:33:31.154 -->> 68 F8 18 00 02 00 0D AF 14 00 01 00 39 40 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0018 00 02 00 --> I帧报文(低字bit0=0,高字bit0=0) 发送序号:12 接收序号:1 (发:低字bit1~bit15,收:高字bit1~bit15)2024/10/04 14:33:31.185 <<-- 68 04 01 00 12 0001 00 12 00 --> S帧报文(低字bit0~bit1=01,高字bit0=0) 接收序号:9