B&R 7IF321.7 RS485/RS422 Serial Port Interface Module

B&R 7IF321.7 RS485/RS422 Serial Port Interface Module

I. Basic Positioning and Series Classification
Brand Origin: B&R (Beckhoff, Austria)
System: System 2003 legacy PLC rack series, screw-in backplane expansion communication module B&R Indus…
Full Model Name: 7IF321.7
Official Description: 1 isolated RS485/RS422 serial interface, multi-node bus networking, backplane screw-in module
Life Cycle: The System 2003 complete machine has been discontinued (EOL), only new machines in stock and disassembled spare parts are circulated; new projects replace with X20 series

Core Hardware Specifications
1. Communication Interface
Channels: 1 universal RS485/RS422, hardware can switch between two electrical modes
Physical Connector: DB9 female socket (screw locking to prevent detachment)
Electrical Isolation: Complete photoelectric isolation between the bus side and the PLC backplane, suppressing ground loop interference, resisting strong on-site electromagnetic interference
Bus Capacity: Supports Multi-drop multi-node bus topology, one bus can connect multiple instruments and frequency converters
Baud Rate: 300 ~ 115200bps adaptive
Board-mounted Status LED: Receive/Transmit indicator lights, intuitive diagnosis of bus communication status
2. Mechanical and Electrical
Installation: 2003 rack standard screw-in cards, direct insertion into the backplane without additional base
Power Supply: Unified power supply from the 2003 rack backplane
Size: Compact narrow card, compatible with 2003 standard rack slots
Weight: Approximately 100g
Operating Temperature: 0℃ ~ +60℃, air-cooled in cabinet; storage – 20℃ ~ +80℃
Certifications: CE, cULus, UKCA, EAC industrial certifications B&R Indus…
3. Supported Communication Protocols (Automation Studio Configuration)
Modbus RTU (most commonly used, for frequency converters, temperature control meters, instruments)
Customized Free Protocol (RS485 free sending and receiving, printing, third-party serial port devices)
B&R Special Serial Port Protocol, ASCII / Binary Custom Messages
Does not support Profibus DP (DP-specific model is 7IF361.70-1)

Compatible Controllers (only System 2003 series CPU)
Can only be paired with Beckhoff 2003 rack CPU, cannot be used in X20/X67/2005 systems:
7CP470.60-1, 7CP474.60-1, 7CP486.60-1, etc. 2003 full series CPUs
The same rack can have multiple 7IF321.7 to expand multiple independent serial bus lines

 Typical Application Scenarios
Connect to third-party frequency converters, temperature control meters, weighing instruments (Modbus RTU collection)
Serial port printers, barcode guns, upper computer serial port debugging communication
Multi-node distributed sensor RS485 networking collection
Old 2003 Beckhoff equipment repair and replacement spare parts
Old-fashioned Beckhoff control systems in metallurgy, packaging, plastic machinery serial port expansion

Comparison of Communication Modules in the Same Series Table
Model Interface Type Core Differences
7IF321.7 RS485/RS422 Isolated Serial Port General free serial port, Modbus RTU (current model)
7IF311.7 RS232 Isolated Serial Port Point-to-point short-distance serial port communication
7IF361.70-1 Profibus DP Master Module DP fieldbus dedicated, cannot be used as Modbus serial port