Modbus is a request/reply protocol that has one Modbus client in its network and may have many Modbus servers. Servers can control only their own internal states and clients can read and write data in them. Modbus is not restricted by the network type, in theory it can use any QIODevice . However, not every plugin supports all classes derived from QIODevice .
每个 Modbus 服务器拥有可以在其中存储数据的 4 个表。
| 名称 | 一字段数据范围 | 客户端权限 |
|---|---|---|
| 离散输入 | 0-1 | 读取 |
| 线圈 | 0-1 | 读/写 |
| 输入寄存器 | 0-65535 (0xffff) | 读取 |
| 保持寄存器 | 0-65535 (0xffff) | 读/写 |
Modbus API 提供了访问 Modbus 设备的一些公共 API：
