Rockwell Automation 1762-Lxxxx MicroLogix 1200 Programmable Controllers - Manual (Page 142)

Publication 1762-UM001G-EN-P - March 2011
E-12 Connect to Networks via RS-232 Interface
Modbus Communication
Protocol 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 1200 controllers support Modbus RTU Master and Modbus RTU
Slave protocol.
For more information on configurating your MicroLogix 1200 controller for
Modbus protocol, refer to the MicroLogix 1200 and 1500 Programmable
Controllers Instruction Set Reference Manual, publication 1762-RM001. For
more information about the Modbus protocol, see the Modbus Protocol
Specifications (available from http://www.modbus.org).
ASCII ASCII provides connection to other ASCII devices, such as bar code readers,
weigh scales, serial printers, and other intelligent devices.
You can use ASCII by configuring the RS-232 port, channel 0 for ASCII driver.
Refer to the MicroLogix 1200 and MicroLogix 1500 Programmable
Controllers Instruction Set Reference Manual, publication 1762-RM001 for
detailed configuration information.