| Name | Type | Section | Description |
|---|---|---|---|
| request | BOOL |
Input | FALSE = no request TRUE = request to send data to the Modbus slave |
| stationAddress | UINT |
Input | Modbus RTU station address |
| mode | USINT |
Input | Mode selection: Specifies the type of request (read, write or diagnostics). Additional information is available in the table of Modbus functions below. |
| startingAddress | UDINT |
Input | Start address in the slave: Specifies the start address of the data that is accessed in the Modbus slave. The valid addresses are listed in the table of Modbus functions below. |
| dataLength | UINT |
Input | Data length: Specifies the number of bits or words this instruction is to access. The valid lengths are listed in the table of Modbus functions below. |
| buffer | ARRAY[*] OF BYTE |
Input/Output | A buffer to be read or written. |
| done | BOOL |
Output | TRUE, if the instruction finished without error |
| busy | BOOL |
Output | TRUE, Modbus master transaction in progress |
| error | BOOL |
Output | TRUE, for one cycle once the instruction has been completed with an error. |
| status | WORD |
Output | Error code. See Parameter Status. |