Communication Protocols
Industrial networking standards and communication methods
A
2 terms
B
2 terms
C
4 terms
CANopen
High-level protocol based on CAN bus used in embedded systems and industrial automation.
CC-Link
Mitsubishi-developed open fieldbus for high-speed control and information networking.
CoAP
Constrained Application Protocol for simple IoT devices with limited resources.
ControlNet
Deterministic network for real-time control applications with scheduled and unscheduled messaging.
D
6 terms
DDS
Data Distribution Service for real-time, scalable, and interoperable data exchange.
DeviceNet
CAN-based network protocol for industrial automation connecting PLCs to devices like sensors and actuators.
DF1
Allen-Bradley serial protocol for point-to-point communication with SLC/MicroLogix PLCs.
DH-485
Data Highway 485, multi-drop network for Allen-Bradley SLC 500 and MicroLogix PLCs.
DH+
Data Highway Plus, proprietary Allen-Bradley token-passing network for PLC-5 systems.
DNP3
Distributed Network Protocol used in SCADA systems for electric and water utilities.
E
3 terms
EtherCAT
Ethernet for Control Automation Technology, ultra-fast industrial Ethernet by Beckhoff.
EtherNet/IP
Industrial Ethernet protocol using standard TCP/IP and CIP (Common Industrial Protocol), primarily used with Rockwell Automation/Allen-Bradley systems.
EtherNet/IP Safety
Safety protocol extension of EtherNet/IP for fail-safe communication.
F
2 terms
H
2 terms
I
5 terms
IEC 60870-5
Telecontrol protocol standard used primarily in European electrical and water systems.
IEC 61850
Standard for electrical substation automation and communication between IEDs.
Interbus
Phoenix Contact ring-based fieldbus with automatic addressing and diagnostics.
IO-Link
Point-to-point serial communication protocol for intelligent sensors and actuators.
ISA100
Wireless standard for industrial automation and control.
L
2 terms
M
10 terms
M-Bus
Meter-Bus protocol for remote reading of utility meters.
Mewtocol
Panasonic's proprietary protocol for communication with FP series PLCs.
Modbus
An open serial communication protocol developed in 1979, widely used for connecting industrial electronic devices, available in RTU (serial) and TCP/IP (Ethernet) variants.
Modbus ASCII
ASCII-encoded Modbus variant, less efficient but human-readable for debugging.
Modbus Plus
Proprietary token-passing variant of Modbus for peer-to-peer communication.
Modbus RTU
Binary implementation of Modbus protocol over serial lines using compact data representation.
Modbus TCP
Modbus protocol encapsulated in TCP/IP for Ethernet-based communication.
Modbus/TCP Security
TLS-secured version of Modbus TCP for encrypted communication.
MQTT
Lightweight publish-subscribe messaging protocol ideal for IIoT and remote monitoring.
MTConnect
Open standard for manufacturing equipment data exchange and CNC machine monitoring.
O
5 terms
OPC A&E
OPC Alarms & Events for standardized alarm and event notification.
OPC Classic
Original OPC specification based on Microsoft COM/DCOM for Windows-based data exchange.
OPC DA
OPC Data Access for real-time data exchange between control devices and HMI/SCADA.
OPC HDA
OPC Historical Data Access for retrieving archived process data from historians.
OPC-UA
OPC-UA
Platform-independent service-oriented architecture for industrial communication, providing secure, reliable data exchange between PLCs, SCADA, MES, and enterprise systems.
P
7 terms
Polling
Master device sequentially requesting data from slave devices.
Powerlink
Ethernet-based real-time protocol using time-slot mechanism for deterministic communication.
PROFIBUS DP
Decentralized Periphery variant of PROFIBUS for high-speed factory automation.
PROFIBUS PA
Process Automation variant of PROFIBUS for intrinsically safe process industries.
PROFINET
Industrial Ethernet standard developed by Siemens/PROFIBUS International for real-time automation, supporting standard and isochronous real-time communication.
PROFINET IRT
Isochronous Real-Time PROFINET for motion control with cycle times under 1ms.
Publish-Subscribe
Messaging pattern where publishers send data to subscribers via broker.
R
5 terms
Request-Response
Communication pattern where client requests data and server responds.
REST API
REST
Representational State Transfer architecture for web services integration with PLCs.
RS-232
Standard serial communication interface for point-to-point connections up to 50 feet.
RS-422
Differential serial standard supporting longer distances and higher speeds than RS-232.
RS-485
Multi-drop serial standard supporting up to 32 devices over 4000 feet.
S
3 terms
SECS/GEM
Semiconductor Equipment Communication Standard for fab automation.
Sercos III
Serial Real-time Communication System for high-performance motion control over Ethernet.
SLMP
Seamless Message Protocol by Mitsubishi for communication with MELSEC PLCs.