Delta RMC151 - Manual (Page 566)

RMC70/150 and RMCTools User Manual
from a Modbus slave, and the slave responds. A number of functions are defined under
Modbus. The following functions are supported by the RMC70:
• Read Multiple Registers (FC 3)
• Read Input Registers (FC 4)
• Write Single Register (FC 6)
• Get Diagnostics (FC 8)
• Write Multiple Registers (FC 16)
• Read/Write Registers (FC 23)
Each of the above functions acts on 4X or Holding registers. These 4X registers are
mapped in the RMC70 as described in the following topic:
• RMC Register Map (Modbus/RTU and /TCP)
6.11. Using Master Controllers
6.11.1. Using Allen-Bradley Controllers via Message
Block
Most Allen-Bradley PLCs and PC-based controllers (ControlLogix, CompactLogix, SLC5/05, PLC-
5, SoftLogix, etc.) support serial RS-232 and Ethernet communications, either built-in or
through an add-on module.
This topic describes how to communicate with the RMC from the Allen-Bradley PLCs via the
Message (MSG) block. For information on using EtherNet/IP I/O with the Logix PLCs, see the
Using Allen-Bradley Controllers via EtherNet/IP topic. For details on using Allen-Bradley's
RSView operator interface with the RMC, see the RSView with the RMC topic.
The Allen-Bradley PLCs can read or write from registers in compatible remote devices such as
other Allen-Bradley PLCs or the RMC. The RMC contains floating point (F) files, all of which are
accessible over serial or Ethernet from the Allen-Bradley PLCs. See the Register Maps for
details on those registers and their addresses.
If you need help setting up your Ethernet network, either consult your network administrator,
or for simple stand-alone networks, see Setting Up a Standalone TCP/IP Network.
For setting up the RMC75S serial settings, see the Configuring Serial Communications topic.
For setting up the RMC75E or RMC150E Ethernet, see the RMC Ethernet Setup topic.
Example Programs
Delta provides example PLC programs to help you quickly set up the communications
between your PLC and the RMC. See the downloads section of Delta's website at
www.deltamotion.com.
Message (MSG) Block
The Allen Bradley PLCs and controllers listed above all use the same ladder logic block to
communicate over Ethernet: the Message (MSG) block. This block takes a number of
parameters, which are briefly described below. For a complete description of the
parameters, refer to Allen-Bradley's Instruction Set Reference Manual for the appropriate
PLC.
MSG Parameters
546 Delta Computer Systems, Inc.