Product Core Brief
- Model: MVI94-MCM-MHI
- Brand: PROSOFT Technology
- Series: 1794 Flex I/O Modbus Master/Slave
- Core Function: Modbus RTU/ASCII master or slave for 1794 Flex I/O adapters
- Product Type: Modbus serial communication module
- Key Specs: 2 serial ports | 800 mA @ 5 V | Mini-DIN connectors | 5,000 words database
- Condition: ⚠️ Obsolete, limited stock (legacy product)
Product Introduction
PROSOFT MVI94-MCM-MHI Modbus Master/Slave module equips Allen-Bradley 1794 Flex I/O systems with dual-port Modbus RTU/ASCII connectivity to legacy PLCs, drives, and RTUs. It mounts behind a standard 1794 adapter and exchanges data as I/O words using ladder logic in the Flex processor.
The module shares a 5,000-word database across two independently configurable serial ports, supports master and slave roles with programmable command lists, and uses locking Mini-DIN connectors with supplied DB9 adapters. Field teams select it for brownfield Flex I/O expansion into existing Modbus networks.
Frequently Asked Questions
Q: Does the MVI94-MCM-MHI support hot-swapping behind a Flex I/O adapter?
A: Honestly, avoid live replacement in operating Flex I/O racks despite backplane tolerance. The module drops both Modbus ports instantly when removed, which faults connected RTUs and drives. Inhibit via processor tags if possible, confirm process tolerance for serial outage, cycle the 1794 adapter to safe state, and verify 5 V stability before swapping hardware.
Q: Is the MVI94-MCM-MHI obsolete, and is there a direct replacement?
A: Documentation lists MVI94 products under legacy support, meaning firmware and spares remain available but new designs should migrate. PROSOFT typically recommends CompactLogix or ControlLogix Modbus modules for greenfield work; for drop-in Flex I/O replacement, confirm any MVI94 successor matches exact I/O image size, serial command limits, and 1794 backplane protocol before stocking up on legacy units.
Q: Will I lose my Modbus configuration when replacing the module?
A: The most common mistake is pulling the card without backing up the configuration file. Connect via the CFG Mini-DIN port using ProSoft Configuration Builder, export the project covering command lists, port parameters, and 5,000-word mapping, then archive your Flex ladder modifications. Restore to new hardware, match assembly instances exactly, download via CFG port, and confirm serial activity before processor Run mode.
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