Allen-Bradley Centerline 2100: PLC Integration and Bucket Options

The Allen-Bradley CENTERLINE 2100 motor control center, manufactured by Rockwell Automation, is the go-to MCC platform for facilities that rely heavily on Allen-Bradley PLCs and automation. Its deep integration with the Rockwell ecosystem makes it uniquely capable for process automation applications.

Overview

The CENTERLINE 2100 has been Rockwell Automation's flagship MCC platform for over three decades. It is designed from the ground up to integrate with Allen-Bradley ControlLogix, CompactLogix, and MicroLogix PLCs through native communication protocols.

Key Differentiator

While all modern MCCs can interface with PLCs through hardwired I/O, the CENTERLINE 2100 offers native network integration through Rockwell's IntelliCENTER technology. This means each MCC bucket can communicate directly with the PLC over a network connection, eliminating extensive point-to-point control wiring.

Specifications

Physical Dimensions

Section width: 20 inches
Section height: 90 inches (standard)
Section depth: 20 inches (standard), 24 inches (deep)
Bucket heights: 6", 12", 18", 24", 36", 48"

Electrical Ratings

Voltage: 600V AC maximum
Horizontal bus: 600A to 4000A
Vertical bus: 300A or 600A
Short-circuit rating: Up to 100 kA
Listed per: UL 845

IntelliCENTER Technology

IntelliCENTER is Rockwell's smart MCC technology that adds network communication to each bucket. It transforms the MCC from a simple power distribution system into an intelligent, connected asset.

Communication Options

DeviceNet The original IntelliCENTER communication protocol. DeviceNet is a CAN-based network that connects each bucket to the PLC:

Each bucket has a DeviceNet node address
PLC can start/stop motors, read status, and monitor diagnostics
Speed: 125/250/500 kbps
Maximum 64 nodes per network

EtherNet/IP The current standard for IntelliCENTER communication:

Uses standard Ethernet infrastructure
Higher bandwidth than DeviceNet
Supports CIP (Common Industrial Protocol) for seamless integration with ControlLogix
Allows web-based monitoring and diagnostics

ControlNet Less common but available for deterministic control applications:

Scheduled and unscheduled messaging
Redundant media options
Deterministic timing for critical control loops

What IntelliCENTER Provides

Each networked bucket can report:

Motor running/stopped status
Overload trip and fault conditions
Motor current (real-time)
Thermal capacity used (percentage of thermal limit)
Starter ready/not ready status
Ground fault detection (with E300 overloads)
Power consumption (watts, vars, VA)
Detailed fault history and event logs

The PLC can command:

Start/stop the motor
Reset overload trips
Change overload parameters
Enable/disable the bucket

Bucket Components

E300 Electronic Overload Relay

The centerpiece of IntelliCENTER technology is the Allen-Bradley E300 electronic overload relay. This is not just an overload device - it is a comprehensive motor management system:

Adjustable overload protection with multiple trip classes
Phase loss, phase unbalance, and phase reversal protection
Ground fault protection
Stall protection
Jam protection
Underload detection
Built-in current transformers
Network communication module

Bulletin 500/509 Contactors

CENTERLINE 2100 buckets use Allen-Bradley Bulletin 500 (NEMA) or Bulletin 509 contactors:

NEMA rated for HP and full-voltage starting
Available in sizes 0 through 6
Proven reliability with millions of installations

Disconnect Options

Bulletin 140M Motor Circuit Protectors: Self-protected combination starters
Molded case circuit breakers: Standard thermal-magnetic or electronic trip
Fused disconnect switches: With Class J or Class R fuses

PLC Integration Details

ControlLogix Integration

The most common integration architecture:

Physical Layer: EtherNet/IP network from PLC to MCC
Communication Module: Each bucket has a communication adapter
Add-On Profile (AOP): Rockwell provides AOPs for each IntelliCENTER device
Programming: Add the MCC devices to the ControlLogix I/O tree just like any other network device
Faceplate: Rockwell provides HMI faceplates for FactoryTalk View

Programming Advantages

With IntelliCENTER, programming motor control is simplified:

No hardwired I/O to configure (reduces wiring by up to 70%)
Standardized data tags for each motor
Pre-built AOPs handle communication configuration
Diagnostic data available without additional instrumentation
Reduce commissioning time significantly

Limitations

Requires Rockwell Automation PLC ecosystem (not cost-effective with other PLC brands)
Network communication adds a layer of complexity to troubleshooting
Communication module failure can prevent motor control (hardwired backup recommended for critical motors)
Higher cost than conventional MCCs

Non-IntelliCENTER Options

Not every CENTERLINE 2100 bucket needs to be networked. Standard (non-IntelliCENTER) buckets are available with conventional hardwired control:

Standard contactors and overloads
Traditional start/stop pushbuttons
Hardwired I/O to PLC
Lower cost per bucket

Many facilities use a mix: IntelliCENTER for critical motors that benefit from monitoring, and conventional buckets for simple applications.

Replacement and Retrofit

For existing CENTERLINE 2100 MCCs, replacement bucket options include:

OEM (Rockwell Automation): Available but expensive and typical lead times of 8-16 weeks
Aftermarket compatible: MCC Depot builds buckets compatible with Allen-Bradley CENTERLINE 2100 MCCs
Retrofit: Upgrade conventional buckets to IntelliCENTER, or replace IntelliCENTER with conventional (either direction)

Bottom Line

The CENTERLINE 2100 is the premier choice for facilities committed to the Rockwell Automation ecosystem. Its native PLC integration reduces wiring, improves diagnostics, and enables predictive maintenance. However, the higher cost and ecosystem lock-in mean it is not the right choice for every application.

Call MCC Depot at 307-442-0382 or email sales@mccdepot.com for CENTERLINE 2100 compatible replacement buckets.