MCG 3221 — Protocol Converter

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Overview

MCG 3221

For terminal operators, automation engineers, maintenance teams, and control-system integrators who need a reliable way to connect mixed tank-gauging equipment to modern SCADA, DCS, or PLC platforms, the MCG 3221 Protocol Converter provides a powerful, microprocessor-based communication bridge. It converts level, temperature, BS&W, and diagnostic data from L&J radar gauges, servo gauges, RTD converters, and interface modules into widely used host protocols such as Modbus RTU/TCP, HART, Tankway, RS-485, and RS-232.
Unlike generic converters that struggle with register compatibility or legacy device support, the MCG 3221 is purpose-built for tank farm automation. It handles legacy and modern field devices simultaneously, uses verified custody-grade register mapping, and supports multiple communication formats to ensure clean, accurate, real-time data flow across diverse platforms.
For facilities upgrading old control systems or connecting mixed-protocol environments, the MCG 3221 offers seamless modernization without hardware replacement, reducing integration cost, simplifying commissioning, and delivering long-term scalability for multi-tank operations.
MCG 3221

Features

Seamless Protocol Bridging

Converts L&J radar, servo, RTD, and interface-module data into Modbus, HART, Tankway, and serial formats for instant host compatibility.

Custody-Grade Register Handling

Ensures accurate level, temperature, and BS&W reporting using verified, error-checked register structures for audit-ready data exchange.

Legacy + Modern Device Support

Allows older gauges and converters to work with new SCADA/DCS systems—preserving investments and avoiding tank farm rewiring.

Multiple parameters

Multipoint Device Integration

Supports communication with multiple L&J field instruments at once, enabling centralized data translation across large facilities.

Intuitive Control

Fast Commissioning

Predefined register blocks, intuitive configuration tools, and plug-and-play setup reduce engineering labor and startup time.

Reliable Data Transmission

Robust Industrial Communications

Offers Modbus RTU/Binary framing, selectable baud rates, parity options, and secure transmission for stable operation in noisy environments.

Details

Applications

  • Mixed-Protocol Tank Farms: Unifies gauge, RTD, and module data so operators can view all tank information in a single SCADA or DCS platform.
  • Custody-Transfer Reporting: Delivers properly formatted level, temperature, and BS&W registers to support accurate and auditable volume calculations.
  • SCADA Modernization Projects: Allows older devices to feed new control systems without replacing gauges or running new wiring—dramatically reducing upgrade cost.
  • Multi-Tank Terminal Automation: Centralizes communications from dozens of tanks, ensuring consistent register mapping and reliable plant-wide visibility.
  • Temperature & RTD Integration: Converts RTD converter data into standardized host-system formats, simplifying temperature reporting for complex inventories.
  • PLC / Host System Interoperability: Bridges mismatched communication formats during PLC or DCS transitions, reducing engineering rework and minimizing downtime.

Technical Specifications

Table Header Table Header
Inputs
Compatible with L&J radar gauges, servo gauges, RTD converters, and IFIC modules.
Outputs / Protocols
Modbus RTU, Modbus TCP, LJ Tankway, HART, RS-485, RS-232, custom options available.
Power Supply
110/220 VAC or 24 VDC.
Processing
Microprocessor-controlled with error-checking for secure data transmission.
Environmental / Construction
  • NEMA 4X / IP66 field enclosure
  • Rack-mount option available
  • Operating Temperature: –40 °C to +70 °C
Integration Capability
  • Supports multiple field devices simultaneously
  • Flexible register mapping for legacy and modern systems
Certifications
  • UL / C-UL listed
  • CE and ATEX options available

Documents and Downloads

Product Flyer

Have a look at the flyer to get all the tech specs and product features. Brochure

User Manual

Read the manual for detailed information and instructions. Manual

Calibrations

Check out a sample cert from our calibration lab. Certificate

Contact Support

If you have a question that we have not covered then just get in touch and we’ll be happy to help.

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FAQs

We have tried to answer the most common questions we are asked here.

In many facilities, field devices use different communication protocols than the central control system (DCS or SCADA). A protocol converter like the MCG 3221 translates these languages, allowing all your devices to communicate seamlessly. This avoids the high cost of replacing functional legacy equipment just to achieve system-wide integration.

The 3221 connects to L&J radar gauges, servo gauges, RTD converters, and interface modules, allowing mixed assets to communicate to SCADA/DCS systems.

Yes. It uses verified, error-checked register mapping to maintain full data fidelity for level, temperature, and BS&W, supporting audit-ready custody measurements.
Absolutely. It allows older L&J instruments to operate with modern platforms such as Modbus TCP-based SCADA or DCS systems, avoiding expensive hardware replacement.
Setup is fast. It includes predefined register blocks, straightforward configuration menus, and standardized communication parameters to reduce engineering time.

Yes. The MCG 3221 is designed for multi-tank environments and can translate data from numerous gauges and converters simultaneously.