Overview
The Modicon 1646-1 is a dedicated serial communication interface module designed for 300 baud rate operation with Modicon programmable logic controllers. This module provides reliable serial connectivity for legacy automation systems and is commonly used in mature industrial installations where low-speed Modbus RTU communication is required. The 1646-1 fits into standard Modicon PLC chassis and facilitates host-to-PLC or PLC-to-device communication over asynchronous serial lines.
Key Features
- Fixed 300 baud operation—no software configuration of baud rate required
- Serial interface module compatible with Modicon SLC and legacy PLC platforms
- Supports Modbus RTU protocol communication over RS-232/RS-485
- Part of established Modicon 1646 interface family (with variants at 1200, 2400, 4800, and 9600 baud)
- Modular design for straightforward installation in Modicon chassis backplane
- Proven reliability in long-running industrial control systems
Technical Specifications
The following specifications define the Modicon 1646-1 module:
- Baud Rate: 300 bps (fixed)
- Interface Type: Serial RS-232/RS-485
- Protocol: Modbus RTU
- Module Type: Communication Interface
- Manufacturer: Modicon (Schneider Electric)
- Condition: Used, fully functional
Typical Applications
- Legacy Modicon PLC system maintenance and repair
- Retrofit installations requiring 300 baud serial connectivity
- Integration with low-speed serial devices and legacy sensors
- Replacement module for failed 1646-1 units in production systems
- Industrial control system upgrades and expansions in mature environments
Compatibility & Replacements
Compatible With
- Modicon SLC (Smooth/Small Line Controller) series
- Modicon legacy PLC platforms
- Modicon chassis backplane installations
- Modbus RTU serial devices and networks
- RS-232 and RS-485 serial networks at 300 baud
Replaces / Drop-In Replacement For
- Modicon 1646-1 (direct match)
- OEM applications calling for Modicon model 1646-1
Works With
- Modbus RTU protocol
- Modicon programming software
- Standard serial communication networks (RS-232, RS-485)
- Legacy Modicon automation systems
