Modbus

[CrazyDanE 0]

Hi there, does anyone here have a code example how send and receive data over Modbus. I am using the serial communication port on the PLC. Set to Modbus RTU Master. My hardware is a micrologix 1100. Kind regards CrazyDane

[BobLfoot 302]

From the Micrologix 1100 User Manual on Page 217 I find the following: "Modbus is a Half-Duplex, master-slave communications protocol. The Modbus network master reads and writes coils and registers. Modbus protocol allows a single master to communicate with a maximum of 247 slave devices. MicroLogix 1100 controllers support Modbus RTU Master and Modbus RTU Slave protocol. For more information on configuring your MicroLogix 1100 controller for Modbus protocol, refer to the MicroLogix 1100 Programmable Controllers Instruction Set Reference Manual, publication 1763-RM001. For more information about the Modbus protocol, see the Modbus Protocol Specifications (available from http://www.modbus.org)." Publication 1763-RM001 can be found thru the Rockwell Automation Literature Library.

[CrazyDanE 0]

Thanks

[BobLfoot 302]

Glad to help - I;'ve never used the Modbus so I'd be curious if you could post how helpful the manuals were and any pitfalls for others to avoid as you commission your system.