Key Technical Specifications
| Parameter | Detail |
|---|---|
| Product Type | BASIC Communication Module |
| Manufacturer | Prosoft Technology |
| Model | MVI56-BAS |
| Slot Requirement | Single-slot ControlLogix module |
| Available RAM | 24,065 bytes |
| Storage | CompactFlash (CF) card slot for BASIC programs |
| User Interface Ports | DH-485, PRT1, PRT2 |
| Supported Functions | BASIC program execution, ASCII device interfacing, DF1 communication, data transfer with ControlLogix processor |
| DF1 Configuration | DF1 half-duplex slave or DF1 full-duplex module |
| Status Indicators | 4 LEDs — Module, Backplane Transfer, Application, Serial Activity |
| Operating Temperature | 0 to 60 °C (32 to 140 °F) |
| Typical Connected Devices | Printers, barcode readers, modems, ASCII-encoded peripherals |
Product Introduction
The Prosoft MVI56-BAS is a single-slot BASIC communication module built for Allen-Bradley ControlLogix systems. It allows legacy BASIC programs — originally written for older platforms such as the 1747-BAS and 1771-DB — to run directly on the ControlLogix backplane.The module provides three communication ports (DH-485, PRT1, and PRT2) and 24,065 bytes of available RAM, with BASIC programs stored on a CompactFlash card. This makes it a practical option for plants that need to preserve existing BASIC logic while migrating to a ControlLogix controller, or for applications that require ASCII device interfacing — barcode readers, printers, and modems — without writing new ladder logic from scratch.
Installation & Configuration Guide
Preparation — about 10 minutes
- Lock out and tag out the ControlLogix chassis power.
- Confirm the target slot is available and compatible with single-slot MVI56 modules.
- Photograph the existing module, CF card, cable connections, and slot position before removal.
- Verify your ControlLogix controller firmware version. Earlier MVI56 modules may not be compatible with Logix 5000 v32+ firmware.
- Prepare the CF card with the correct BASIC program file.
Removal — about 5–10 minutes
- Disconnect all serial cables (DH-485, PRT1, PRT2).
- Release the module from the backplane connector.
- Remove the module from the chassis.
- Label cables if connectors are not keyed.
Installation — about 10 minutes
- Insert the MVI56-BAS into the designated ControlLogix slot.
- Confirm the module seats fully and the backplane connector engages.
- Insert the CompactFlash card with the BASIC program.
- Reconnect serial cables to the correct ports.
- Do not force connectors — bent pins on PRT1 or PRT2 are a common field failure.
Power-On & Test — about 10 minutes
- Restore chassis power.
- Check the four LED indicators: Module, Backplane Transfer, Application, and Serial Activity.
- Confirm the controller recognizes the module in the I/O configuration.
- Verify BASIC program execution and data transfer with the ControlLogix processor.
- Test serial communication with the connected ASCII device before returning to production.
Troubleshooting Quick Reference
| Symptom | Most Likely Cause | First Check |
|---|---|---|
| Module LED not lit | No backplane power or module not seated | Check chassis power and reseat the module |
| Backplane Transfer LED off | Controller does not recognize module | Verify I/O configuration and slot assignment |
| BASIC program not running | CF card missing, corrupt, or wrong file | Reseat CF card and verify program file |
| No serial communication | Wrong port, cable, or DF1 setting | Check DH-485/PRT1/PRT2 wiring and DF1 mode |
| Data transfer errors | Ladder logic mismatch or timing issue | Review example ladder file and tag mapping |
| Intermittent failures | Loose CF card or connector | Reseat CF card and check terminal connections |
Dimensions, Mounting & Wiring Notes
- Mounting: ControlLogix single-slot backplane mounting.
- Ports: DH-485, PRT1, PRT2 — used for communication, BASIC program transfer, ASCII communication, programming, or DF1 communication.
- Wiring Notes: Confirm cable pinouts for each serial port before connecting. DH-485 and DF1 use different electrical and protocol configurations.
- CF Card: The CompactFlash card stores BASIC programs and can be used to export programs to a PC or transfer them to another module.
FAQ
What does the MVI56-BAS actually do?
It runs legacy BASIC programs on a ControlLogix backplane and provides serial ports for ASCII device communication, DF1, and data transfer with the processor.Can I use this module with any ControlLogix firmware?
Not necessarily. Earlier MVI56 modules may not be compatible with Logix 5000 v32+ firmware. Check your controller firmware version and the module’s firmware revision before installing.I have an old 1747-BAS program. Will it run on the MVI56-BAS without changes?
The module is designed to convert legacy BASIC programs from 1747-BAS and 1771-DB platforms to ControlLogix, but program compatibility should be verified. Some adjustments may be needed depending on I/O addressing, serial configuration, and data transfer logic.Do I need ladder logic to use this module?
Yes. Ladder logic is required to transfer data between the MVI56-BAS and the ControlLogix processor. Example ladder files are typically provided with the module.What happens if I lose the CF card?
The BASIC program is stored on the CF card. If you do not have a backup, you will need to recover the program from the original source, another machine, or the system integrator who created it.Is this module still a safe choice for a new installation?
It depends on the application. If you are migrating an existing BASIC program to ControlLogix, it can be a practical solution. For a completely new design, evaluate whether modern communication modules or direct ControlLogix programming would be more maintainable long-term.
