Allen-Bradley 20-COMM-C ControlNet Communication Adapter

The Allen-Bradley 20-COMM-C, also cataloged as the 20-COMM-C Communication Adapter, operates as a dedicated hardware component for ControlNet network interfacing within PowerFlex architecture networks. The module establishes a direct data bridge between the host drive's Drive Peripheral Interface (DPI) and a deterministic ControlNet link, executing real-time transmission of scheduled I/O data and unscheduled configuration messaging. Operating at a fixed 5 Mbps data rate, this interface module inserts directly into the dedicated internal communication slot of the drive or external communication kit, drawing physical operational current over the internal backplane connection.

Hardware Specifications

Profinet / EtherNet/IP Deterministic Networks and I/O Density Scaling

Within distributed ControlNet architectures, data transmission routines interact concurrently with peripheral Profinet / EtherNet/IP deterministic networks via plant-wide bridging modules. The 20-COMM-C manages drive parameter mapping to maintain consistent I/O density scaling during large-scale network expansions. By securing a fixed 5 ms Requested Packet Interval (RPI) minimum rate, the adapter offloads real-time motion and speed loop processing from the main trunk line, suppressing latency variances across high-density nodes and preventing physical drive dropouts during intensive asynchronous message cycles.

Frequently Asked Questions

Q: Does the 20-COMM-C adapter support online hot-swap operations while the host drive is energized?

A: No. The adapter must never be inserted or removed while power is applied to the host drive or the external DPI communication kit. Disconnecting the module during operation will disrupt the DPI link, fault the drive, and risk corruption of the internal parameter registers.

Q: How is network-side electrical consumption managed across the dual BNC ControlNet channels?

A: The network electrical consumption of this module is zero. All internal optical isolation components and transceivers on the ControlNet side derive their operational power completely from the 5 VDC backplane current supplied by the host drive.

Field Installation Guidelines

• Drive Power Isolation: Remove all primary AC power (up to 400 VAC, 3-phase circuits) and auxiliary control power from the host drive. Wait for the internal DC bus capacitors to fully discharge before opening the enclosure cover.
• Redundant BNC Medium Termination: Connect the primary network cable to Channel A. For high-availability configurations, connect the redundant network trunk cable to Channel B. Ensure all unused BNC ports are terminated with proper 75-ohm coaxial terminators.
• DPI Cable Routing Restrictions: Keep internal RJ45 and DPI connection cables physically segregated from high-voltage motor leads and incoming AC power lines to block induced electromagnetic interference from causing packet loss.
• Grounding Integrity: Ensure the module grounding tabs make firm physical contact with the drive chassis ground terminal upon insertion. This mechanical connection provides the low-impedance path required by the internal optical isolation circuits to deflect high-frequency noise transients.