ABB Implementation

Modbus TCP/IP for ABB

Ethernet-based variant of Modbus using TCP/IP. Combines simplicity of Modbus with speed and scalability of Ethernet.

Type: Industrial EthernetSpeed: 10/100/1000 MbpsReleased: 1999Organization: Modbus Organization

1 Gbps capable

Bandwidth

Unlimited (network dependent)

Max Nodes

100m per segment (with switches: unlimited)

Max Distance

Real-Time

Protocol Overview

ABB AC500 Automation Builder (CODESYS) provides Modbus TCP through SysLibModbusTCP library. Works with built-in Ethernet on TB521-ETH or CM577-ETH modules.

When to Use Modbus TCP/IP

Choose Modbus TCP/IP for SCADA systems, plant-wide networks, remote monitoring, or when integrating industrial equipment with IT systems.

ABB Hardware Requirements

Compatible Communication Modules

TB521-ETH (AC500-eCo built-in)

CM577-ETH (AC500 Ethernet + serial)

TB511-ETH (AC500-eCo V3)

AI562-S (I/O module with Modbus TCP)

Wiring Details

Network Setup

Configure IP in Automation Builder device tree. Supports 10/100Mbps. Port 502 standard.

ABB Software & Programming

Function Blocks & Instructions

MODBUSMASTER_TCP (SysLibModbusTCP)

MODBUSSLAVE_TCP

MODBUS_CLIENT_REQUEST

TCP_Connection management

ABB Code Example

fbModbusTCPMaster(
  config := tcpConfig,
  request := tcpRequest,
  xExecute := xExecute,
  pData := ADR(readBuffer),
  => xDone => xDone,
  => eState => eState
);
// config.sIPAddr := '192.168.1.10'
// config.uiPort := 502

ABB-Specific Implementation Notes

CODESYS-based, portable to other CODESYS controllers. eState provides connection state machine status. Supports connection pooling for multiple slaves. Typical response time 5-15ms on 100Mbps network.

Technical Specifications

Physical Layer

Physical Layer: IEEE 802.3 Ethernet
Cable Type: Cat5e/Cat6 Ethernet
Topology: Star, Tree, Ring
Power Over Cable: No

Data Layer

Data Link: TCP/IP
Encoding: Binary
Error Detection: TCP checksum
Frame Size: 1500 bytes (MTU)

Performance

Scan Time: 1-10ms typical
Deterministic: No
Real-Time: No

Certification

Certification Required: No
License Cost: Free (open standard)
Version: Current

Advantages & Disadvantages

Advantages

✓High speed (up to 1 Gbps)
✓Uses standard Ethernet infrastructure
✓Unlimited nodes and distance (with switches)
✓Easy IT integration
✓Simple protocol (Modbus heritage)
✓Open standard and free
✓Remote access capability

Disadvantages

✗Not deterministic (not real-time)
✗No built-in security (requires VPN/firewall)
✗Higher latency than dedicated fieldbuses
✗Requires managed switches for large networks
✗No device profiles or configuration tools

Common Use Cases & Applications

SCADA systems

Plant-wide data collection

Building management systems

Remote monitoring

Enterprise system integration

Large distributed systems

Industry Adoption

Adoption LevelVery High

Market Share25-35% of industrial Ethernet

Geographic PresenceWorldwide

Primary Industries

Oil & GasWater/WastewaterBuilding AutomationManufacturingEnergy

Supported Message Types

Read Coils

Read Discrete Inputs

Read Holding Registers

Write Single Coil

Write Single Register

Write Multiple Registers

Supported PLC Brands

Siemens Allen-Bradley Mitsubishi Schneider Electric Beckhoff ABB Rockwell

Phoenix Contact

Wago

Protocol Comparisons

Modbus TCP/IP vs EtherNet/IP

Modbus TCP is simpler and open; EtherNet/IP offers better diagnostics and CIP ecosystem

View Detailed Comparison →

Quick Links

Alternative Protocols

Related Standards

IEC 61131-3
International standard for programmable logic controller programming languages. Defines 5 programmin...
IEC 61131 Series
Complete series of international standards for programmable logic controllers covering hardware, sof...