20-COMM-E — EtherNet/IP Communication Adapter for AC Drives

The 20-COMM-E is an EtherNet/IP communication adapter that plugs into the peripheral option port of compatible AC drives. Once installed, it gives the drive a standard RJ-45 Ethernet port and makes it a full EtherNet/IP node — controllable from any EtherNet/IP-capable controller via cyclic I/O messaging and explicit messaging for parameter access.

Without a communication card, most drives in this family are limited to hardwired control: discrete start/stop inputs, an analog speed reference, and a relay output for run confirmation. Adding the 20-COMM-E changes the picture entirely. Speed reference, direction, acceleration override, fault reset — all become programmable outputs from the controller. Drive status, output frequency, output current, fault codes — all become readable tags in the controller program. For any installation where the drive is part of a larger automated system, this level of integration is difficult to achieve through wiring alone.

Specifications

Parameter	Value
Part Number	20-COMM-E
Protocol	EtherNet/IP (CIP)
Network Speed	10/100 Mbps, auto-negotiate
Connector	1 × RJ-45
IP Address Assignment	BOOTP, DHCP, or static (via drive HIM or software)
I/O Messaging	Class 1 (cyclic) — control and status data
Explicit Messaging	Class 3 / UCMM — parameter read/write via MSG instruction
Compatible Drive Families	755, 525, 40, 70, 700 (peripheral option port variants)
Power Source	Powered from drive option port (no external supply)
Operating Temperature	−10°C to 60°C
Standards	EtherNet/IP conformance tested, UL, CE

Network Architecture and Drive Integration

The 20-COMM-E connects to the drive via a proprietary DSI (Drive Serial Interface) internal bus through the option port connector — not Ethernet. The card then translates between DSI and EtherNet/IP, presenting the drive's control and status parameters as standard CIP objects on the network. To the controller and the rest of the EtherNet/IP network, the drive appears as a standard I/O device with a defined input and output data assembly.

In Studio 5000, the drive is added to the controller's EtherNet/IP device tree using the Generic Ethernet Module configuration or the drive-specific Add-On Profile (AOP) if installed. The AOP gives named tag access to drive parameters directly, making the program more readable. Without the AOP, parameters are accessed as numeric indices via explicit MSG instructions — workable, but less intuitive during commissioning and maintenance.

Drive Data Accessible Over EtherNet/IP

Through the cyclic I/O connection, the controller can read and write the core drive control data every scan cycle — typically at RPIs between 10 and 20 ms for drive control applications. Commonly used data in each direction:

Output from controller to drive: Logic command word (start, stop, direction, fault reset, jog), speed reference (in Hz or RPM depending on scaling), acceleration time override.
Input from drive to controller: Status word (running, faulted, at speed, direction), output frequency, output current, DC bus voltage, active fault code.

Parameter reads and writes beyond the standard I/O assembly — adjusting ramp times, reading thermal load percentage, writing preset speeds — use explicit messaging via the MSG instruction. These don't run cyclically; they execute on demand from the program logic.

FAQ

Q: Does the 20-COMM-E work on a standard office Ethernet switch?

Electrically it will connect, but a standard unmanaged office switch is not recommended for industrial EtherNet/IP drive control. Use an industrial-rated managed switch that supports EtherNet/IP traffic prioritization and is rated for the panel's temperature and vibration environment.

Q: Can the drive still be controlled from its hardwired inputs when the 20-COMM-E is installed?

Yes, depending on the drive's control source parameter setting. The drive can be configured to accept commands from the network, the hardwired terminals, or the HIM. The control source hierarchy is set in the drive parameters — verify which source has priority in your installation.

Q: What happens to drive operation if the EtherNet/IP connection drops?

The drive's response to a lost network connection is configurable — options include fault, coast to stop, ramp to stop, or continue at last commanded speed. Set the communication loss action in the drive parameters to match the application's fail-safe requirement before commissioning.

Q: Can multiple controllers communicate with one 20-COMM-E simultaneously?

Only one controller can hold the Class 1 (cyclic) I/O ownership connection at a time — this is the control connection. Multiple controllers or devices can read drive parameters via explicit messaging (Class 3) simultaneously without conflicting with the I/O owner.

Q: How is the card firmware updated?

Firmware updates are applied using ControlFLASH or ControlFLASH Plus software from a PC on the same EtherNet/IP network as the card. The drive must be stopped (not running) before initiating a firmware update, and the process takes a few minutes. Always verify the firmware version compatibility between the card and the host drive before updating.

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