modbus_protocol
Modbus
In WebHMI, such syntax of addressing ModBus (RTU/ASCII/TCP) registers is defined:
| Register address | Description | Data type | Read(FC1))/Write(FC) |
|---|---|---|---|
| Cx | Coils. X — output number (valid range is 0..65535). Examples: C1, C3, C44 | Bit | Read(0x01)/Write(0x05) |
| DIx | Discrete Inputs. X — input number (valid range 0 ..65535). Examples: DI1, DI3, DI44, DI45000 | Bit | Read(0x02)/— |
| HRx | Holding Registers. X — register address (valid range 0..65535). Examples: HR1, HR3, HR44, HR65043 | Bit, Byte, Word, Double Word | Read(0x03)/Write(0x06) |
| MHRx | Identical to HRx. The difference is that the writing in such registers occurs using the Modbus function No. 16 (Preset Multiple Register). | Bit, Byte, Word, Double Word | Read(0x03)/Write(0x16) |
| IRx | Input Registers. X — register address (valid range 0..65535). Примеры: IR1, IR3, IR44, IR65043 | Bit, Byte, Word, Double Word | Read(0x04)/— |
ATTENTION! By default, for double word reading, two queries each by one word will be used. To explicitly set double-word reading with one query (multiple read), you must enable grouping in the connection properties.
1)
FC - function code used
modbus_protocol.txt · Last modified: 2022/01/15 10:43 by 127.0.0.1