Product Core Brief
- Model: MVI94-MCM
- Brand: ProSoft Technology
- Series: Allen-Bradley Flex I/O 1794 platform
- Core Function: Modbus Master/Slave over dual serial ports for SLC/MicroLogix
- Product Type: Modbus communication module
- Key Specs: 800 mA @ 5 VDC | 2 serial ports | Modbus RTU/ASCII | 0 °C to 60 °C
- Condition: New Original (New Surplus) — verify with supplier test records and accessories
Product Introduction
ProSoft MVI94-MCM mounts in Allen-Bradley Flex I/O 1794 racks and provides dual-port Modbus RTU/ASCII Master/Slave connectivity for SLC 5/03-05 or MicroLogix processors. Each port handles independent networks to drives, RTUs, meters, or instruments using a shared 10,000-word database updated via ladder block transfers over the Flex bus.
Independent port configuration supports mixed Master/Slave roles with up to 100 commands per Master port, RTS timing control, and floating-point variants. The module requires external 24 VDC power to the base and serial adapter cables for field wiring.
Frequently Asked Questions
Q: Does the MVI94-MCM support hot-swapping in a Flex I/O rack?
A: Flex I/O racks do not support live module changes; power down the 1794 base and rack before swapping. At 800 mA @ 5 VDC draw, it affects power budget significantly, and removing it kills all Modbus traffic on both ports instantly. Plan as full rack outage with safe process state and verify 1794 power supply headroom post-install.
Q: Is the MVI94-MCM obsolete, and what are replacement options?
A: ProSoft lists MVI94-MCM under legacy Flex I/O products alongside MVI94-MCM-MHI variant; migration typically targets CompactLogix MVI69/MVI69L Modbus modules or ControlLogix MVI56E-MCM. Ladder logic block transfers differ from newer tag-based methods, so expect configuration rework. Confirm lifecycle letters before spares procurement.
Q: Will I lose my SLC/MicroLogix program or Modbus config when replacing the module?
A: Processor program stays intact; module failure does not erase SLC/MicroLogix flash. Modbus database, command lists, and port parameters store in module NVRAM—if unbacked you reload from scratch using serial Configuration/Debug port and ProSoft tools. Record firmware via front panel before pull, backup .cfg file, and match jumper settings on replacement.
Q: Are these factory-new or refurbished when sold as surplus?
A: Secondary market units usually represent New Surplus from Flex I/O rack upgrades or OEM spares, not active production. Expect original ProSoft/MHI labeling, supplied Mini-DIN to DB9 cables, clean Flex bus connector for “New Original” claims; rack dust or missing adapters mark refurbished—demand serial traceability and comms bench test.
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