Allen-Bradley Route

Allen-Bradley Overview

The ALLEN_BRADLEY route enables communication with Rockwell Automation PLCs using native protocols. It supports ControlLogix, CompactLogix, PLC5, SLC500, Micro800, and MicroLogix families with TAG-based addressing and bidirectional communication.

Allen-Bradley PLCs use tag-based programming. Access PLC tags directly by their symbolic names for the most intuitive configuration.

Basic Syntax

DEFINE ROUTE AllenBradleyPLC WITH TYPE ALLEN_BRADLEY
    ADD ALLEN_BRADLEY_CONFIG
        WITH IP "192.168.1.100"
        WITH DEVICE_FAMILY '0'
        WITH SLOT '0'
    ADD MAPPING ProcessData
        WITH EVERY 500 MILLISECONDS
        ADD TAG Temperature
            WITH ADDRESS "MainProgram:Temperature"
            WITH DATA_TYPE "REAL"
            WITH SOURCE_TOPIC "plc/temperature"

Supported Device Families

Device Family	Parameter Value	Description
ControlLogix	`0`	ControlLogix 5000 series
PLC5	`1`	PLC/5 processors
SLC500	`2`	SLC 500 processors
ControlLogix PLC5	`3`	PLC5 emulation on ControlLogix
Micro800	`4`	Micro800 series
MicroLogix	`5`	MicroLogix 1100/1400
Omron	`6`	Omron NJ/NX (CIP compatible)

ControlLogix (0) is the most common setting for modern Allen-Bradley systems including CompactLogix and ControlLogix PLCs.

Connection Configuration

ALLEN_BRADLEY_CONFIG Parameters

string

required

PLC IP address.

DEVICE_FAMILY

integer

Device family type (0-6, see table above). Default: 0 (ControlLogix).

PORT

integer

Communication port. Default: 44818.

SLOT

integer

CPU slot number in chassis. Default: 0.

PATH

string

Routing path for accessing PLCs through network infrastructure. Format: port,slot pairs separated by commas.

TIMEOUT

integer

Connection timeout in milliseconds. Default: 5000.

Connection Examples

ControlLogix/CompactLogix
MicroLogix
Through Backplane
Multi-Hop Routing

Direct connection to ControlLogix or CompactLogix:

ADD ALLEN_BRADLEY_CONFIG
    WITH IP "192.168.1.100"
    WITH DEVICE_FAMILY '0'
    WITH SLOT '0'
    WITH TIMEOUT '5000'

Connection to MicroLogix 1100/1400:

ADD ALLEN_BRADLEY_CONFIG
    WITH IP "192.168.1.50"
    WITH DEVICE_FAMILY '5'
    WITH TIMEOUT '5000'

Access PLC in slot 2 through Ethernet module in slot 0:

ADD ALLEN_BRADLEY_CONFIG
    WITH IP "192.168.1.100"
    WITH DEVICE_FAMILY '0'
    WITH PATH "1,2"
    WITH TIMEOUT '5000'

Route through multiple network bridges:

ADD ALLEN_BRADLEY_CONFIG
    WITH IP "192.168.1.100"
    WITH DEVICE_FAMILY '0'
    WITH PATH "1,0,2,192.168.2.50,1,0"
    WITH TIMEOUT '10000'

Multi-hop paths: port,slot,port,IP,port,slot where each segment navigates through chassis and networks.

Tag Addressing

Allen-Bradley uses symbolic tag names. The address format depends on the tag scope:

Scope	Format	Example
Controller	`TagName`	`Temperature`
Program	`Program:TagName`	`MainProgram:Counter`
Array element	`TagName[index]`	`Temperatures[0]`
UDT member	`TagName.Member`	`Motor1.Speed`

Data Types

Data Type	Logix Type	Size	Description
`BOOL`	BOOL	1 bit	Boolean value
`SINT`	SINT	8 bits	Signed 8-bit integer
`INT`	INT	16 bits	Signed 16-bit integer
`DINT`	DINT	32 bits	Signed 32-bit integer
`LINT`	LINT	64 bits	Signed 64-bit integer
`USINT`	USINT	8 bits	Unsigned 8-bit integer
`UINT`	UINT	16 bits	Unsigned 16-bit integer
`UDINT`	UDINT	32 bits	Unsigned 32-bit integer
`ULINT`	ULINT	64 bits	Unsigned 64-bit integer
`REAL`	REAL	32 bits	32-bit floating point
`LREAL`	LREAL	64 bits	64-bit floating point
`STRING`	STRING	Variable	ASCII string

TAG Configuration

Complete TAG Example

ADD TAG MotorSpeed
    WITH ADDRESS "Motor1.ActualSpeed"
    WITH ADDRESS_TYPE "SYMBOL"
    WITH DATA_TYPE "REAL"
    WITH SOURCE_TOPIC "plc/motor1/speed"
    WITH SCALING "1"
    WITH OFFSET "0"
    WITH UNIT "RPM"
    WITH DECIMAL_PLACES "2"
    WITH MIN_VALUE "0"
    WITH MAX_VALUE "3600"
    WITH DEADBAND "10"
    WITH PUBLISH_MODE "JSON"
    WITH WRITABLE "false"
    WITH DESCRIPTION "Motor 1 actual speed in RPM"

TAG Parameters

Address Configuration

ADDRESS

string

required

Tag name in PLC (e.g., MainProgram:Temperature, Motor1.Speed, Temperatures[0]).

ADDRESS_TYPE

string

Address type: SYMBOL (default) or PATH.

DATA_TYPE

string

required

Logix data type: BOOL, SINT, INT, DINT, LINT, USINT, UINT, UDINT, ULINT, REAL, LREAL, STRING.

Value Transformation

SCALING

double

Multiplier for value transformation. Default: 1.0.

OFFSET

double

Offset added after scaling. Default: 0.0.

DECIMAL_PLACES

integer

Decimal places in output. Default: 2.

Filtering

MIN_VALUE

double

Minimum allowed value.

MAX_VALUE

double

Maximum allowed value.

DEADBAND

double

Minimum change to trigger publish. Default: 0.0.

Publishing

SOURCE_TOPIC

string

required

MQTT topic for read values.

DESTINATION_TOPIC

string

MQTT topic for write commands.

PUBLISH_MODE

string

Output format: VALUE_ONLY or JSON. Default: VALUE_ONLY.

UNIT

string

Engineering unit for documentation.

DESCRIPTION

string

Human-readable description.

Write Configuration

WRITABLE

boolean

Allow writing to this tag. Default: false.

Event-Based Operations

For on-demand operations:

ADD EVENT ReadOnDemand
    WITH SOURCE_TOPIC "ab/commands/read"
    WITH DESTINATION_TOPIC "ab/responses/read"
    WITH QUERY '{"operation": "READ", "variable": "MainProgram:Counter", "data_type": "DINT"}'

Complete Examples

Read controller-scoped tags:

DEFINE ROUTE ControlLogixBasic WITH TYPE ALLEN_BRADLEY
    ADD ALLEN_BRADLEY_CONFIG
        WITH IP "192.168.1.100"
        WITH DEVICE_FAMILY '0'
        WITH SLOT '0'
    ADD MAPPING ProcessTags
        WITH EVERY 500 MILLISECONDS
        ADD TAG Temperature
            WITH ADDRESS "Temperature"
            WITH DATA_TYPE "REAL"
            WITH SOURCE_TOPIC "plc/temperature"
            WITH UNIT "°F"
        ADD TAG Pressure
            WITH ADDRESS "Pressure"
            WITH DATA_TYPE "REAL"
            WITH SOURCE_TOPIC "plc/pressure"
            WITH UNIT "PSI"
        ADD TAG Running
            WITH ADDRESS "SystemRunning"
            WITH DATA_TYPE "BOOL"
            WITH SOURCE_TOPIC "plc/running"

Access tags within specific programs:

DEFINE ROUTE ProgramTags WITH TYPE ALLEN_BRADLEY
    ADD ALLEN_BRADLEY_CONFIG
        WITH IP "192.168.1.100"
        WITH DEVICE_FAMILY '0'
        WITH SLOT '0'
    ADD MAPPING MainProgramTags
        WITH EVERY 500 MILLISECONDS
        ADD TAG Counter
            WITH ADDRESS "MainProgram:ProductionCounter"
            WITH DATA_TYPE "DINT"
            WITH SOURCE_TOPIC "plc/production/count"
        ADD TAG CycleTime
            WITH ADDRESS "MainProgram:CycleTimeMs"
            WITH DATA_TYPE "DINT"
            WITH SOURCE_TOPIC "plc/production/cycletime"
            WITH UNIT "ms"
        ADD TAG BatchNumber
            WITH ADDRESS "MainProgram:CurrentBatch"
            WITH DATA_TYPE "STRING"
            WITH SOURCE_TOPIC "plc/production/batch"

Access User Defined Type (UDT) members:

DEFINE ROUTE MotorControl WITH TYPE ALLEN_BRADLEY
    ADD ALLEN_BRADLEY_CONFIG
        WITH IP "192.168.1.100"
        WITH DEVICE_FAMILY '0'
        WITH SLOT '0'
    ADD MAPPING Motor1Data
        WITH EVERY 200 MILLISECONDS
        ADD TAG Speed
            WITH ADDRESS "Motor1.ActualSpeed"
            WITH DATA_TYPE "REAL"
            WITH SOURCE_TOPIC "motor1/speed"
            WITH UNIT "RPM"
        ADD TAG Current
            WITH ADDRESS "Motor1.Current"
            WITH DATA_TYPE "REAL"
            WITH SOURCE_TOPIC "motor1/current"
            WITH UNIT "A"
        ADD TAG Running
            WITH ADDRESS "Motor1.Running"
            WITH DATA_TYPE "BOOL"
            WITH SOURCE_TOPIC "motor1/running"
        ADD TAG Faulted
            WITH ADDRESS "Motor1.Faulted"
            WITH DATA_TYPE "BOOL"
            WITH SOURCE_TOPIC "motor1/faulted"
        ADD TAG SpeedCommand
            WITH ADDRESS "Motor1.SpeedCmd"
            WITH DATA_TYPE "REAL"
            WITH SOURCE_TOPIC "motor1/speed/cmd"
            WITH WRITABLE "true"
            WITH DESTINATION_TOPIC "motor1/speed/set"

Read array elements:

DEFINE ROUTE ArrayData WITH TYPE ALLEN_BRADLEY
    ADD ALLEN_BRADLEY_CONFIG
        WITH IP "192.168.1.100"
        WITH DEVICE_FAMILY '0'
        WITH SLOT '0'
    ADD MAPPING SensorArrays
        WITH EVERY 1 SECOND
        ADD TAG Temp0
            WITH ADDRESS "Temperatures[0]"
            WITH DATA_TYPE "REAL"
            WITH SOURCE_TOPIC "sensors/temp/0"
        ADD TAG Temp1
            WITH ADDRESS "Temperatures[1]"
            WITH DATA_TYPE "REAL"
            WITH SOURCE_TOPIC "sensors/temp/1"
        ADD TAG Temp2
            WITH ADDRESS "Temperatures[2]"
            WITH DATA_TYPE "REAL"
            WITH SOURCE_TOPIC "sensors/temp/2"
        ADD TAG Status0
            WITH ADDRESS "StatusBits[0]"
            WITH DATA_TYPE "BOOL"
            WITH SOURCE_TOPIC "status/bit/0"

Read values and write setpoints:

DEFINE ROUTE ControlLoop WITH TYPE ALLEN_BRADLEY
    ADD ALLEN_BRADLEY_CONFIG
        WITH IP "192.168.1.100"
        WITH DEVICE_FAMILY '0'
        WITH SLOT '0'
    ADD MAPPING TempControl
        WITH EVERY 200 MILLISECONDS
        ADD TAG PV
            WITH ADDRESS "TIC100.PV"
            WITH DATA_TYPE "REAL"
            WITH SOURCE_TOPIC "control/tic100/pv"
            WITH UNIT "°F"
            WITH PUBLISH_MODE "JSON"
        ADD TAG SP
            WITH ADDRESS "TIC100.SP"
            WITH DATA_TYPE "REAL"
            WITH SOURCE_TOPIC "control/tic100/sp"
            WITH UNIT "°F"
            WITH WRITABLE "true"
            WITH DESTINATION_TOPIC "control/tic100/sp/set"
            WITH MIN_VALUE "32"
            WITH MAX_VALUE "212"
        ADD TAG Output
            WITH ADDRESS "TIC100.OUT"
            WITH DATA_TYPE "REAL"
            WITH SOURCE_TOPIC "control/tic100/output"
            WITH UNIT "%"
        ADD TAG Auto
            WITH ADDRESS "TIC100.Auto"
            WITH DATA_TYPE "BOOL"
            WITH SOURCE_TOPIC "control/tic100/auto"
            WITH WRITABLE "true"
            WITH DESTINATION_TOPIC "control/tic100/auto/set"

CompactLogix typically in slot 0:

DEFINE ROUTE CompactLogix WITH TYPE ALLEN_BRADLEY
    ADD ALLEN_BRADLEY_CONFIG
        WITH IP "192.168.1.50"
        WITH DEVICE_FAMILY '0'
        WITH SLOT '0'
        WITH TIMEOUT '5000'
    ADD MAPPING IOData
        WITH EVERY 100 MILLISECONDS
        ADD TAG DigitalInputs
            WITH ADDRESS "Local:1:I.Data"
            WITH DATA_TYPE "DINT"
            WITH SOURCE_TOPIC "compactlogix/di"
        ADD TAG DigitalOutputs
            WITH ADDRESS "Local:2:O.Data"
            WITH DATA_TYPE "DINT"
            WITH SOURCE_TOPIC "compactlogix/do"
            WITH WRITABLE "true"
            WITH DESTINATION_TOPIC "compactlogix/do/set"

Troubleshooting

Connection Failed

Verify IP address is correct
Check DEVICE_FAMILY matches your PLC type
Ensure SLOT is correct (usually 0 for CompactLogix)
Verify firewall allows port 44818
Check PLC is in Run mode

Tag Not Found

Verify tag name matches exactly (case-sensitive)
For program-scoped tags, include program name: MainProgram:TagName
Check tag exists in PLC project
Ensure tag is not local to a routine

Path Errors

Verify PATH format: port,slot pairs
Check network modules are configured correctly
For IP in path, use: port,slot,port,IP,port,slot
Increase TIMEOUT for multi-hop routes

Write Operations Fail

Ensure WRITABLE is set to “true”
Verify PLC is in Remote Run mode
Check tag is not constant or read-only
Verify value is within data type range

Data Type Mismatch

Verify DATA_TYPE matches PLC tag definition
REAL for floating point, DINT for 32-bit integers
Check array vs. single value configuration

Next Steps

EtherNet/IP

CIP explicit messaging for Allen-Bradley and compatible devices.

Industrial Overview

Common patterns for all industrial routes.

Quick Start

MQTT Broker

LoT Language

LoT Notebooks

Actions

Routes

Models

Rules

Allen-Bradley Overview

Basic Syntax

Supported Device Families

Connection Configuration

ALLEN_BRADLEY_CONFIG Parameters

Connection Examples

Tag Addressing

Data Types

TAG Configuration

Complete TAG Example

TAG Parameters

Event-Based Operations

Complete Examples

Troubleshooting

Next Steps

EtherNet/IP

Industrial Overview

Quick Start

MQTT Broker

LoT Language

LoT Notebooks

Actions

Routes

Models

Rules

​Allen-Bradley Overview

​Basic Syntax

​Supported Device Families

​Connection Configuration

​ALLEN_BRADLEY_CONFIG Parameters

​Connection Examples

​Tag Addressing

​Data Types

​TAG Configuration

​Complete TAG Example

​TAG Parameters

​Event-Based Operations

​Complete Examples

​Troubleshooting

​Next Steps

EtherNet/IP

Industrial Overview

Allen-Bradley Overview

Basic Syntax

Supported Device Families

Connection Configuration

ALLEN_BRADLEY_CONFIG Parameters

Connection Examples

Tag Addressing

Data Types

TAG Configuration

Complete TAG Example

TAG Parameters

Event-Based Operations

Complete Examples

Troubleshooting

Next Steps