The Modbus_slave control allows your application to easily exchange data with modbus master devices connected either serially or via a TCP/IP network. The control supports up to four simultaneous COM port connections plus the modbus/TCP network connection. Your application simply passes a pointer to one or more data arrays, and the data is immediately accessible to any connected master controller using either the modbus RTU or modbus ASCII transmission mode.
Using the Modbus_slave control involves three basic steps:
No knowledge of the modbus protocol is required to use the control. Your application simply defines the data as it is to be represented to the master, (i.e. slave node address, data type, and address), and the control performs all the message formatting and interaction with the Windows COM and network drivers to forward the information to connected modbus master devices as requested. Feed-back to your application is supplied by the control as an Event message if the data is modified by a master.
Last Updated: September 14, 1996