Product Overview
The Allen-Bradley 1769-SM2 is a Compact I/O communication module designed to bridge CompactLogix and MicroLogix 1500 controllers with variable frequency drives over Drive Serial Interface (DSI) or MODBUS RTU networks. This industrial automation module enables seamless integration with PowerFlex 4-class and PowerFlex 7-class drives via the 20-COMM-H RS485 adapter, making it an essential component for modern drive control systems.
With a single-slot width and support for both DIN rail and panel mounting, the 1769-SM2 fits easily into existing panels. It draws only 350 mA at 5V DC from the backplane, ensuring minimal power consumption while maintaining reliable communication.
Technical Specifications
The 1769-SM2 delivers robust performance across its communication protocols. Key specifications include:
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Supported Protocols: DSI and MODBUS RTU
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DSI Data Transfer Speed: 19200 bps
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MODBUS Transfer Speeds: 300, 600, 1200, 2400, 4800, 9600, 19200, or 38400 bps
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Current Draw: 350 mA @ 5V DC; 0 mA @ 24V DC (supplied by Compact I/O power supply)
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Operating Temperature: -10…50 °C (14…122 °F)
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Storage Temperature: -40…85 °C (-40…185 °F)
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Vibration: 5g, 10 to 500 Hz
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Operating Shock: 30g, 11 ms
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Power Supply Distance Rating: 8 modules
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Wire Type: Copper-90°C
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Solid Wire Size: 22–14 AWG
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Stranded Wire Size: 22–16 AWG
These specifications ensure the 1769-SM2 operates reliably in demanding industrial environments, whether installed in a control cabinet or on a machine.
Applications & Use Cases
The 1769-SM2 excels in applications requiring multi-drive control and flexible communication. Common scenarios include:
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Conveyor Systems: Synchronize multiple PowerFlex 4-class drives over DSI, with each channel supporting up to five drives.
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Pump and Fan Control: Use MODBUS RTU to integrate with existing SCADA systems, allowing remote monitoring and control.
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Packaging Machinery: Achieve precise speed control and quick changeovers by connecting CompactLogix controllers to PowerFlex 7-class drives via the 20-COMM-H adapter.
The module's ability to operate in single-drive or multi-drive mode provides flexibility, and its 19200 bps DSI speed ensures fast data exchange for real-time control.
Installation & Setup
Mount the 1769-SM2 on a DIN rail or panel using the integrated clips. Connect it to the Compact I/O backplane, ensuring it is within the power supply distance rating of 8 modules. For DSI communication, use a 2-conductor twisted-pair network wiring system with a maximum cable distance of 1219 m (4000 ft). For PowerFlex 4-class drives, keep the cable distance under 10 m (32.8 ft) to maintain signal integrity.
Configure the module for either single or multi-drive operation. For multi-drive setups, use ControlFLASH via the CompactLogix backplane to update firmware. Verify that the module is not installed in areas with volatile or corrosive gases, vapors, or dust.
Maintenance & Reliability
Routine maintenance focuses on ensuring clean power and proper grounding. Inspect wiring connections periodically to prevent loose terminals. The 1769-SM2 operates reliably within -10…50 °C, so ensure adequate ventilation in enclosures. With no moving parts, the module offers long service life, reducing downtime and maintenance costs.
Given its shock and vibration ratings (30g, 11 ms and 5g, 10-500 Hz), the module withstands harsh industrial conditions, making it a dependable choice for continuous operation.
Compatibility & Integration
The 1769-SM2 is compatible with CompactLogix and MicroLogix 1500 controllers, and can also be used with remote 1769-based adapters like the 1769-ADN. It supports both DSI and MODBUS RTU protocols, enabling integration with a wide range of drives and PLCs. The module is part of the CompactLogix product line and is available in Series A and B.
Selection Guide & Purchasing Advice
When selecting the 1769-SM2, confirm your controller model (CompactLogix or MicroLogix 1500) and the drive types you plan to connect. For PowerFlex 7-class drives, ensure you have the 20-COMM-H RS485 communication adapter. Verify your network wiring meets the specified distances and use copper wire rated for 90°C.
PLC Source PRO offers genuine Allen-Bradley 1769-SM2 modules with fast shipping and competitive pricing. Ensure you order the correct part number to guarantee compatibility with your existing system.