The Modbus Router provides intelligent data routing between EtherNet/IP and Modbus (serial Modbus-RTU232, Modbus-RTU485, and Ethernet Modbus-TCP). The Modbus Router allows the user to integrate Modbus devices into a Rockwell Automation Logix platform (ControlLogix or CompactLogix) or PLC (SLC or MicroLogix) with minimal effort.
The module can be configured in one of six router modes:
Scheduled Tag
The MBR/B operates as a Modbus Client and transfers data between a Modbus device and a number of Logix tags, using a preconfigured scheduled. No Logix or remote device configuration is required. The MBR/B can execute up to 100 Modbus message instructions (e.g., Modbus Holding Register Read) and exchange the Modbus data with Logix tags in up to three Logix Controllers. Each Modbus Message instruction is executed at one of four configured rates. The Modbus data is exchanged using only one of the available ports (Ethernet TCP, RTU232, or RTU485).
Reactive Tag
The MBR/B operates as a Modbus Server and transfers data between Modbus Clients and a number of Logix tags, using a preconfigured tag map. No Logix or remote device configuration is required. The MBR/B can map up to 100 Modbus message instructions (e.g., Modbus Holding Register Read) and exchange the Modbus data with Logix tags in up to three Logix Controllers. The Modbus data is exchanged using only one of the available ports (Ethernet TCP, RTU232, or RTU485).
Unscheduled
The MBR/B operates as a Modbus Client and sends Modbus messages to Modbus devices when receiving a Logix Message Instruction. This provides the user with complete control (from Logix) of which Modbus instructions must be sent and at which frequency. The Modbus data is exchanged using only one of the available ports (Ethernet TCP, RTU232, or RTU485).
Enhanced
The user can decide if the MBR/B is operating as a Modbus Client or Server as well as if the MBR/B is operating as an EtherNet/IP Target or EtherNet/IP Originator.
In Enhanced Mode the MBR/B can be configured in any one of the four combinations:
Modbus Client - EtherNet/IP Target
Modbus Client - EtherNet/IP Originator
Modbus Server - EtherNet/IP Target
Modbus Server - EtherNet/IP Originator
Modbus Mode
Modbus Server
The data from the configured EtherNet/IP devices (using either Class 1 Assemblies, Explicit messaging or Logix Direct-to-Tag reads/writes) will be written to, or read from, the module’s internal Modbus Registers using the Internal Map. These registers can be accessed by a remote Modbus Client using either Modbus TCP, Modbus RTU232, Modbus RTU485, or any simultaneous combination of these.
Modbus Client
The data from the configured EtherNet/IP devices (using either Class 1 Assemblies, Explicit messaging or Logix Direct-to-Tag reads/writes) will be written to, or read from, the module’s internal Modbus Registers using the Internal Map. The Modbus Auxiliary Map can then be used to configure the Modbus data exchange between multiple remote Modbus Server devices and the module’s internal Modbus registers. The Modbus communication can be via Modbus TCP, Modbus RTU232, Modbus RTU485, or any simultaneous combination of these.
EtherNet/IP Mode
EtherNet/IP Target
As an EtherNet/IP target, the module can exchange the Class 1 data with devices on the Modbus network:
EtherNet/IP Class 1 connection
Here a remote EtherNet/IP device (e.g. a Logix controller) establishes between 1 and 5 Class 1 connections to the module. Modbus data can be mapped into four separate input and output class 1 cyclic connections to the Logix controller (allowing up to 2KB input and 2KB output to be exchanged at the requested packet interval – RPI).
EtherNet/IP Originator
As an EtherNet/IP originator, the module can use one of two methods to read and write data to and from the Modbus network:
EtherNet/IP Explicit Messaging
This allows the MBR/B to exchange data with up to 10 EtherNet/IP devices. The module can use either Class 3 or Unconnected Messaging (UCMM) to Get and Set data in the remote EtherNet/IP devices.
Direct-To-Tag
This allows the MBR/B to exchange data with a Logix controller without the need to write any application code (e.g. ladder) in Studio 5000. The Modbus data is directly read from, or written to, Logix tags.
EtherNet/IP Class 1 connection
Modbus data can be mapped to a maximum of 10 EtherNet/IP devices using input and output class 1 cyclic connections. This will allow the MBR/B to “own” the EtherNet/IP target device and exchange Modbus data using the EtherNet/IP device’s input and output assemblies.
Bridge
The MBR/B can operate as a transparent link for Modbus between different media (TCP, RTU232, and RTU485). This allows a Modbus client on Modbus TCP to communicate with Modbus devices on RS232 or RS485 and vice versa.
Concentrator
In Concentrator Mode, the MBR/B will collect data from a number of Modbus devices and provide the consolidated data to one or more Modbus Clients. The MBR/B will be a Modbus Server on one port, and Modbus Clients on the other ports. This will allow a Modbus SCADA to efficiently read the data from multiple Modbus devices, because the data from the various Modbus devices have been concentrated into the MBR/B.
The Modbus Router is configured using the Aparian Slate application. This program can be downloaded from www.aparian.com free of charge.
The module provides a range of statistics, a Modbus packet analyzer, and an Internal Modbus Register viewer to help fault find any problems.
The Modbus Router supports Modbus on three ports which can be configured from the Slate environment: Modbus-RTU232 (Serial), Modbus-RTU485 (Serial), and Modbus-TCP (Ethernet).
The Modbus Router uses isolated RS232 and isolated RS485 for Modbus serial communication providing better noise immunity. The RS232 and RS485 ports use a terminal block for convenient installation.
The MBR/B supports security services allowing the user to configure various levels of module security.
The module has two Ethernet ports and supports Device-Level-Ring (DLR) architectures.
A built-in webserver provides detailed diagnostics of system configuration and operation, including the display of Modbus operation and communication statistics, without the need for any additional software.