Moxa ioPAC 8020-5-M12-C-T [46/66] Mx_modbus_tcp_master_ioctl

Developer's Guide for Moxa RTU Controllers Programmer's Guide

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MX_Modbus_Tcp_Master_Ioctl

INT32 MX_Modbus_Tcp_Master_Ioctl(UINT32 sHandle, UINT8 unitId, UINT32 rwTimeoutMs);

This function configures the unit identifier and timeout values of the Modbus/TCP connection.

Input Parameters

sHandle

TCP connection handle

unitId

Unit identifier

rwTimeoutMs

timeout value in milliseconds

Output Parameters

None

Return Value

MODBUS_ERR_OK

MODBUS_ERR_LIB_INIT

MODBUS_ERR_PARAM

MODBUS_ERR_NOT_OPENED

MX_Modbus_Tcp_Master_Read_Coils

INT32 MX_Modbus_Tcp_Master_Read_Coils(UINT32 sHandle, UINT16 startAddr , UINT16

coilCount, UINT8 byteCoils[]);

This function performs Modbus function code 0x1; it reads multiple coils and puts the output in parameter

byeCoils.

Input Parameters

sHandle

TCP connection handle

startAddr

Modbus address

coilCount

The numbers of read coils

Output Parameters

byteCoils

This parameter holds the read coils value; users should provide enough buffer space. For

example, if coildCount=9, the buffer size of byteCoils should be at least 2 bytes.

Return Value

Modbus standard error codes are mapped to values 16 to 24. Refer to the header file libmoxa_pgm.h.

MODBUS_ERR_OK

MODBUS_ERR_LIB_INIT

MODBUS_ERR_PARAM

MODBUS_ERR_NOT_OPENED

MODBUS_ERR_RESP

MODBUS_ERR_TIMEOUT

MODBUS_ERR_SOCKET