TF6100 vs. TF6105
With TF6100 TwinCAT 3 OPC UA and TF6105 TwinCAT 3 OPC UA Pub/Sub, Beckhoff offers two TwinCAT 3 functions for OPC UA communication. Both products are based on OPC UA, but they implement different communication models and address different requirements.
TF6100 is primarily used when applications require service-oriented access to an OPC UA information model. Clients can establish a connection to a server, browse its address space, read and write values, subscribe to value changes, call methods, and use other OPC UA functions.
TF6105 is designed for the cyclic or event-driven distribution of predefined datasets. Publishers send messages without having to process individual read requests for each recipient. Depending on the selected transport method, the messages are distributed directly via UDP or via an MQTT message broker.
The two products therefore complement each other. Which product is suitable for a particular application depends primarily on how information is to be identified, retrieved, and exchanged.
TF6100: Service-oriented access with OPC UA client/server
TF6100 implements the established OPC UA client/server communication model. An OPC UA client establishes a secure connection and session with an OPC UA server and then uses standardized services to interact with the server's address space.
The TF6100 product package includes the following components:
- TwinCAT OPC UA Server, which makes data and functions from TwinCAT runtime environments available via an OPC UA address space.
- TwinCAT OPC UA Client, which allows TwinCAT applications to access remote OPC UA servers.
- TwinCAT OPC UA Gateway, which can aggregate subordinate OPC UA servers and provide an OPC COM DA integration.
TwinCAT OPC UA Server can represent PLC variables and other TwinCAT runtime data as nodes in a structured address space. Clients can examine the available nodes and their metadata at runtime. It is therefore not necessary to specify in advance which elements are to be exchanged.
Typical client/server operations include:
- browsing the address space
- reading and writing variable values
- creating subscriptions for value changes
- calling methods
- receiving alarms and events
- accessing historical data
- examining data types, references, and semantic information
- importing companion specifications
This makes the TF6100 particularly well-suited for communication with HMIs, SCADA systems, MES and ERP applications, engineering tools, diagnostic applications, and other systems that require flexible access to machine information.
TF6105: Distribution of datasets using OPC UA Pub/Sub
TF6105 implements the publisher/subscriber communication model defined in Part 14 of the OPC UA specification. The product is integrated into the TwinCAT runtime via the so-called OPC UA RT device and supports both publisher and subscriber configurations.
A publisher aggregates selected process values into a PublishedDataSet and sends the corresponding NetworkMessages at a configured interval. Subscribers receive the messages, identify the relevant dataset, decode its fields, and link the received values to their local process image.
TF6105 supports two basic transport modes:
- UDP with UADP encoding for direct communication without a broker, including unicast and multicast scenarios.
- MQTT with UADP or JSON encoding for broker-based distribution across network boundaries as well as in IT or cloud environments.
Since the datasets to be exchanged and their mappings are configured in advance, the runtime does not need to browse a remote address space or perform individual read operations for each value. As a result, the publisher-subscriber model is particularly well-suited for efficient, cyclic data distribution and for communication with multiple recipients.
Typical applications include:
- controller-to-controller and machine-to-machine data exchange
- distribution of process values to multiple recipients
- cyclic communication with defined publishing intervals
- broker-based distribution of machine data via MQTT
- integration of automation data into edge or cloud applications
- decoupling data producers and data consumers
TF6105 does not provide a browsable server address space and does not offer client/server services such as Read, Write, Call, Historical Access, or Alarms & Conditions. The product transfers the fields from the configured datasets.
An overview of the key differences
Feature | TF6100 | TF6105 |
|---|---|---|
OPC UA communication model | Client/server | Publisher/subscriber |
Main purpose | Flexible, service-oriented access to an information model | Efficient distribution of predefined datasets |
Main roles | Server and client | Publisher and subscriber |
Communication relationship | A stateful connection and session between the client and the server. | The publisher and subscriber are decoupled at the application level. |
Data selection | A client browses the address space or knows the NodeIds and makes the choice of which nodes to use. | Dataset fields are chosen during the engineering phase and mapped in the configuration. |
Runtime detection | The address space, nodes, references, data types, and metadata can be browsed. | Subscribers typically require the appropriate configuration or exchanged publisher-subscriber model configuration information. |
Value access | Read, write, and client/server subscriptions | Cyclic or event-driven dataset messages |
Method calls | Supported via the client/server service model | Not part of the publisher-subscriber model dataset exchange |
Alarms and historical data | Supported by the TwinCAT OPC UA Server. | Are not provided as corresponding client/server services. |
Topology | Typically, a client connects to a server; multiple clients can set up independent connections. | Suitable for one-to-one, one-to-many, and many-to-many distribution patterns. |
Transport examples | OPC UA client/server transport with secure sessions | UDP or MQTT |
Message encoding | OPC UA client/server service messages | UADP; JSON is also available with MQTT |
Broker required | No | No for UDP; yes for MQTT |
Typical focus | Interoperability, information models, diagnostics, commands, and flexible data access | Cyclic process data exchange, scalable distribution, and decoupling of producers and consumers |