Description

Integrating serial Modbus connectivity directly into Allen-Bradley 1794 FLEX I/O systems is efficiently achieved using the MVI94-MCM communication module. Designed to function as a bridge between the Modbus protocol and the Rockwell Automation backplane, this module enables a host processor to interface seamlessly with field telemetry devices, SCADA systems, instruments, and PLC-based networks. The MVI94-MCM operates as either a Modbus Master or a Modbus Slave, offering versatile network configuration options for complex industrial systems.

The module occupies a single slot in the 1794 backplane and provides a reliable communication link using serial communication. It features optical isolation to protect sensitive control equipment from electrical noise and ground loop hazards. System configuration and maintenance are simplified through a dedicated, hardware-handshaking serial port, while application communications are handled via a jumper-selectable secondary port.

Features

• FLEX I/O Compatibility: Installs directly into any standard Allen-Bradley 1794 backplane slot.
• Dual-Port Architecture: Provides a dedicated serial configuration port (PRT1) and a multi-protocol serial application port (PRT2).
• Protocol Versatility: Configurable as a Modbus Master or Modbus Slave device.
• Robust Isolation: Application serial port includes 500V optical isolation from the backplane to prevent electrical noise propagation.
• Physical Interface Selectivity: Jumper-selectable configurations on the application port support RS-232, RS-422, and RS-485 communication standards.
• Diagnostic Diagnostics: LEDs display module status, backplane transfer, application status, and active serial port communication activity.

Applications

• SCADA and telemetry interface integration in oil and gas pipelines.
• Power distribution monitoring and electrical substation automation.
• Water and wastewater remote terminal unit (RTU) coordination.
• Inter-system PLC and DCS networking in chemical processing facilities.

Technical Specifications

Connections and Interfaces

Installation Guidelines

• Terminal Base Mounting: Mount the module securely onto a compatible 1794 terminal base unit before applying power to the backplane.
• Jumper Settings: Ensure the hardware jumper settings on the module side panel are configured correctly for the desired physical interface (RS-232, RS-422, or RS-485) prior to mounting and commissioning.
• External Power Supply Wiring: Connect a clean 12 to 24 VDC external power source to the designated terminal base connections to power the transceiver circuits.
• Grounding: For optimal optical isolation performance and noise reduction, ensure the terminal base and cabinet housing are properly connected to a low-impedance earth ground.