Allen-Bradley 20-COMM-M PowerFlex Communication Adapter

The Allen-Bradley 20-COMM-M, also cataloged as the 20-COMM-M communication adapter, operates as a dedicated hardware component for executing Modbus TCP protocol translation within PowerFlex drive platforms. Configured to interface directly with the DPI (Drive Peripheral Interface) port of the host drive, this adapter facilitates bidirectional data exchange between the industrial network and the motor controller. It provides deterministic connectivity through an RJ45 physical layer, supporting variable data rates up to 100 Mbps. The unit manages up to 30 concurrent TCP connections, ensuring synchronization with supervisory control systems at a minimum Requested Packet Interval (RPI) of 5 ms.

Suffix Breakdown & Model Matrix

The 20-COMM-M is a standardized communication interface module designed for internal installation within compatible PowerFlex drive frames or external DPI communication kits. The "20-COMM" prefix identifies the product line as a PowerFlex communication accessory, while the "-M" suffix designates the specific Modbus TCP protocol implementation. The module is packaged as a blank cover interface, suitable for panel-mount enclosures rated at IP 20/NEMA Type 1.

Hardware Specifications

Firmware Flash Compatibility and I/O Density Scaling

The 20-COMM-M supports firmware flash compatibility, allowing the end user to update the adapter’s internal logic to align with specific drive firmware revisions. This ensures that the communication path remains compatible with the host drive's control parameters. The adapter is designed to scale I/O density requirements for complex motor control topologies by mapping drive-specific objects into the Modbus register map. This mapping is essential for maintaining deterministic network performance when multiple drives are integrated into a single Modbus TCP segment, ensuring that the host drive maintains the required control loops without network-induced latency.

Frequently Asked Questions (FAQ)

Q: Does the 20-COMM-M require an external power supply to operate?

A: No, the adapter is powered directly through the DPI connector by the host drive or the external DPI communication kit. It draws 350 mA at 5 VDC.

Q: Can the 20-COMM-M be hot-swapped while the PowerFlex drive is running?

A: While the DPI interface allows for modularity, it is recommended to stop the drive and isolate power before inserting or removing the communication adapter to prevent unexpected configuration faults or DPI communication interrupts.

Field Installation Guidelines

1. Ensure the host PowerFlex drive is de-energized and all capacitive discharge time requirements have been met before accessing the DPI interface port.
2. Remove the existing interface blank cover from the drive.
3. Align the 20-COMM-M connector pins with the DPI interface port on the drive or the external communication kit.
4. Press the module firmly into place until the locking tabs engage, ensuring a secure physical and electrical connection.
5. Connect the shielded Cat5e or Cat6 Ethernet cable to the RJ45 port on the adapter. Ensure the cable path maintains adequate separation from high-voltage motor leads to prevent electromagnetic interference.
6. Verify the DPI and Network LED status indicators upon drive power-up to confirm the module has been recognized by the drive firmware.