Rockwell Prosoft ILX34-MBS485 Modbus Serial Module

Product Overview

The ProSoft ILX34-MBS485 is a Modbus Serial Communication Module designed for Rockwell Automation CompactLogix L1 controllers and Point I/O adapters. It provides a single RS-485 serial port supporting both Modbus RTU Master and Slave modes, enabling CompactLogix systems to communicate with Modbus RTU devices such as variable frequency drives, motor starters, power meters, and remote terminal units (RTUs). With baud rates up to 38.4 kbps and support for up to 247 node addresses, this module is a cost-effective solution for serial device integration.

Key Specifications

• Part Number: ILX34-MBS485
• Product Type: Modbus Serial Communication Module
• Series: ProSoft ILX34 for CompactLogix/Point I/O
• Platform: CompactLogix L1, Point I/O adapters
• Serial Port: 1 × RS-485 (2-wire or 4-wire)
• Baud Rates: 2400, 4800, 9600, 19200, 38400 bps
• Data Format: 7 or 8 data bits; 1 or 2 stop bits; None, Even, Odd parity
• Protocol: Modbus RTU (Master or Slave); Modbus ASCII (Slave only)
• Node Address Range: 1 to 247
• Supported Function Codes: 01, 02, 03, 04, 05, 06, 08, 15, 16
• Configuration: Studio 5000 with ProSoft AOI; RSLogix 5000
• Operating Temperature: -20°C to 70°C (standard)
• Storage Temperature: -40°C to 85°C

Features & Benefits

• Compact Form Factor: Designed for CompactLogix L1 and Point I/O, minimizing control panel space
• Dual Mode: Configurable as Modbus RTU Master or Slave for flexible network roles
• Wide Baud Range: Supports both legacy (2400 bps) and modern (38.4 kbps) serial devices
• Studio 5000 Integration: Add-On Instruction (AOI) simplifies configuration and tag mapping
• Diagnostic LEDs: TX/RX and status LEDs provide immediate visual communication feedback
• Isolated Serial Port: Electrical isolation protects against ground loops and transient voltage

Applications

• CompactLogix integration of legacy Modbus RTU variable frequency drives
• Building automation power meter and energy monitoring networks
• Water/wastewater SCADA with distributed Modbus RTU telemetry
• Material handling conveyor motor control via serial Modbus

Installation Guide

1. Power Down: Turn OFF CompactLogix/Point I/O rack power before module installation
2. Slot Selection: Insert the ILX34-MBS485 into the appropriate adapter slot
3. Serial Wiring: Connect RS-485 A/B lines to the terminal block; observe polarity
4. Termination: Install 120 Ω termination resistors at both ends of the RS-485 bus if required
5. Studio 5000 Setup: Import the ProSoft AOI and add the module to your I/O configuration
6. Parameter Configuration: Set baud rate, parity, node address, and master/slave mode via module properties
7. Tag Mapping: Map Modbus registers to CompactLogix controller tags using the AOI
8. Testing: Use ModScan or similar tool to verify serial communication before full commissioning

FAQ

Q: Is this module compatible with CompactLogix L2/L3?
A: The ILX34-MBS485 is specifically designed for CompactLogix L1 and Point I/O adapters. For L2/L3, consider MVI69-MCM or MVI69-MBS.

Q: Can I use this for Modbus ASCII?
A: Yes, the module supports Modbus ASCII mode in Slave configuration only. RTU mode is recommended for new designs.

Q: What is the maximum cable length?
A: RS-485 supports up to 1,200 meters (4,000 feet) at lower baud rates. Use shielded twisted-pair cable and maintain proper termination.

Q: How many devices can I poll as a master?
A: As a Modbus RTU Master, the module can communicate with up to 247 slave devices, though practical limits depend on baud rate and response timeout settings.

Selection Tips

• Verify your CompactLogix L1 or Point I/O adapter has available slots before ordering
• For multi-port serial applications, consider MVI69-MCM (dual serial) instead
• Use shielded twisted-pair cable (Belden 9841 or equivalent) for reliable RS-485 communication
• Plan node addressing carefully to avoid conflicts with existing Modbus devices
• If operating in high-RF environments, use ferrite cores on serial cables near the module