ProSoft MVI56-MDA4 – Four-port serial data acquisition for ControlLogix plants

From my experience with ProSoft’s MVI56 family, the MVI56-MDA4 is designed for Rockwell Automation ControlLogix users who need multiple serial channels in one slot—typically for tying legacy field instruments and smart devices into a Logix platform without adding standalone gateways. You might notice that it’s a fit for multi-drop serial networks where flow computers, barcode scanners, weigh scales, drives, or protection relays still speak Modbus RTU/ASCII or plain ASCII.

One thing I appreciate is the straightforward Logix integration: you configure the channels, map the data to tags, drop in the sample logic or AOI, and you’re collecting values on scan. In many cases, that means far less panel space, fewer power supplies, and simpler wiring compared to four separate converters.

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• Warranty: 365 days
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Key Features

• Four independent serial channels – Typically used for RS-232/RS-422/RS-485 multi-drop networks, so you can connect several legacy devices at once.
• ControlLogix-native integration – Backplane data exchange to Logix tags; sample ladder/AOI support usually shortens commissioning time.
• Modbus RTU/ASCII and raw ASCII – Practical for mixed fleets: meters on Modbus, barcode scanners or printers on ASCII at the same time.
• Deterministic data handling – Fixed-size data blocks mapped to UDTs make controller logic simpler and easier to troubleshoot.
• Diagnostics on the front end – Status LEDs and channel-level counters help catch wiring, baud, or framing issues quickly.
• Single-slot footprint – Frees cabinet space compared with multiple external gateways and power supplies.

Technical Specifications

Where it fits best

• Oil & gas: polling multiple flow computers on one RS-485 trunk while keeping a spare channel for a calibrator.
• Food & beverage: bringing weigh scale ASCII strings and label printer status into Logix tags for recipe tracking.
• Power & utilities: interfacing relays and meters that still speak Modbus RTU without extra DIN-rail gateways.
• Intralogistics: connecting barcode readers and handheld scanners directly to the PLC program.

A maintenance lead told us their favorite part is the four-channel density: “We replaced three little RS-485 converters and a rat’s nest of power taps with this one module—troubleshooting is just easier now.”

Related or Supporting Products

• ProSoft MVI56E-MCM – Modbus RTU Master/Slave for ControlLogix; ideal if you need dedicated Modbus function blocks and higher throughput on two serial ports.
• ProSoft MVI56E-GSC – Generic Serial Communication; good for custom ASCII protocols or proprietary serial framing.
• ProSoft MVI56-MNET – Modbus TCP/IP Client/Server; use when your field devices are Ethernet-based instead of serial.
• ProSoft PLX31-EIP-MBTCP – Standalone EtherNet/IP to Modbus TCP/IP gateway; helpful when you want to keep serial ports free and bridge Ethernet networks.
• ProSoft MVI56-PDPMV1 – PROFIBUS DP-V1 Master; choose this if the devices are on PROFIBUS rather than Modbus/ASCII.

Installation & Maintenance

• Cabinet & chassis – Install in a 1756 ControlLogix chassis. Keep ambient 0–60 °C, allow airflow above/below the slot, and follow UL508A wiring practices.
• Grounding & shielding – For RS-485 multi-drop, use twisted pair with shield; terminate at the ends (typically 120 Ω) and ground shield at one point to reduce noise.
• Addressing & baud – Keep device baud, parity, and addressing consistent. Mixing frame settings is a common cause of timeouts.
• Programming – Use ProSoft Configuration Builder to set channel parameters and memory map; import AOI/sample code into Studio 5000 to speed up tag mapping.
• Routine checks – Periodically review error counters, CRC errors, and retries. Clean connectors, verify terminations, and back up configuration after any changes.
• Firmware – Check for ProSoft firmware updates during planned outages; improvements often add protocol robustness or diagnostics.

Quality & Certifications

• Certifications: CE, UL/cUL, RoHS (typical for ProSoft ControlLogix modules)
• Manufacturer policy: ProSoft standard limited warranty typically 1 year
• Store guarantee: 365-day warranty as stated above