Modbus Master/Slave Communications Module

MVI71-MCM

The MVI71 Modbus Master/Slave Communication Module allows Rockwell Automation PLC processors to interface easily with other Modbus protocol compatible devices.

Compatible devices include not only Modicon PLCs (which all support the Modbus protocol) but also a wide assortment of end devices. The module acts as an input/output module between the Modbus network and the Rockwell Automation backplane. The data transfer from the processor is asynchronous from the actions on the Modbus network. A 5000-word register space in the module exchanges data between the processor and the Modbus network.

Features and Benefits

The inRAx Modbus Master/Slave Communication Module is designed to allow PLC processors to interface easily with Modbus protocol-compatible devices and hosts.

The MVI71-MCM module acts as an input/output module between the Modbus network and the Rockwell Automation backplane. The data transfer from the PLC processor is asynchronous from the actions on the Modbus network. A 5000-word register space in the module exchanges data between the processor and the Modbus network.

Many host SCADA packages support the Modbus protocol, while devices commonly supporting the protocol include several PLCs, as well as many other third party devices in the marketplace. (For a partial list of devices that speak Modbus, please visit the ProSoft Tested section of the ProSoft Technology web site).

General Specifications

• Single Slot - 1771 backplane compatible
• The module is recognized as an Input/Output module and has access to processor memory for data transfer between processor and module
• Ladder Logic is used for data transfer between module and processor.
• Configuration data obtained through user-defined ladder. Sample ladder file included

Applications

Applications using the Modbus Communication Module can be found in many industrial sectors and in the following applications

• Foreign device data concentrator
• Pipelines and offshore platforms
• Food processing
• Mining
• Pulp and paper
• SCADA communications

Functional Specifications

Some of the general specifications include:

• Support for the storage and transfer of up to 5000 registers to/from the PLC processor's data files
• Module memory usage that is completely user definable
• Two ports to emulate any combination of Modbus master or slave device
• Supports Enron version of Modbus protocol for floating point data transactions.
• Some of the general specifications include:
• Support for the storage and transfer of up to 5000 registers to/from the PLC processor's data files
• Module memory usage that is completely user definable
• Two ports to emulate any combination of Modbus master or slave device
• Supports Enron version of Modbus protocol for floating point data transactions.

Slave Specifications

The MVI71-MCM module accepts Modbus function code commands of 1, 2, 3, 4, 5, 6, 8, 15, 16, 17, 22 and 23 from an attached Modbus master unit. A port configured as a Modbus slave permits a remote master to interact with all data contained in the module. This data can be derived from other Modbus slave devices on the network, through a master port, or from the PLC processor.

Master Specifications

A port configured as a virtual Modbus master device on the MVI71-MCM module actively issues Modbus commands to other nodes on the Modbus network. One hundred commands are supported on each port. Additionally, the master ports have an optimized polling characteristic that polls slaves with communication problems less frequently. The PLC processor can be programmed to control the activity on the port by actively selecting commands from the command list to execute or issuing commands directly from the ladder logic.

Hardware Specifications

Ordering Information

Distributors:
Place your order by email to orders@prosoft-technology.com:, fax to +1 661-716-5101.

Sales and Support: