TwinCAT® ADS

The Automation Device Specification (ADS) protocol is a transport layer integrated into TwinCAT® systems, developed by Beckhoff. It enables OIBus to access PLC data by uniquely identifying each data item through a distinct address in the controller.

OIBus uses the ads-client library to communicate with TwinCAT® systems.

Specific Settings

Connection

Local AMS Server (TwinCAT Runtime)

Use this configuration if TwinCAT is installed on the same machine and network as OIBus.

Local AMS Server Settings

Setting	Description	Example Value
Net ID	Unique address of the PLC, resembling an IP address with two additional numeric values.	127.0.0.1.1.1
PLC Port	Communication endpoint for the PLC.	851

Note: When using a local AMS server, you do not need to specify the Router address, Router TCP port, Client AMS Net ID, or Client ADS port.

Remote AMS Server

Use this configuration if TwinCAT is installed on a remote machine.

Remote AMS Server Settings

Setting	Description	Example Value
Net ID	Unique address of the PLC.	192.168.1.10.1.1
PLC Port	Communication endpoint for the PLC.	851
Router Address	IP address or domain name of the AMS Router.	192.168.1.100
Router TCP Port	Port used by the AMS Router for communication.	48898
AMS Net ID	Client identifier for connecting to the TwinCAT runtime.	192.168.1.50.1.1
ADS Client Port	(Optional) Port used by the client. If left empty, the AMS server assigns a random port.	1200

Static Routes

To enable communication, configure Static Routes using the TwinCAT Static Routes tool. The AMS Net ID specified in the tool must match the one in the OIBus configuration.

danger

OIBus supports only one remote ADS connector at a time. To connect to multiple PLCs simultaneously, use a local AMS server.

Advanced Settings

Advanced Settings

Setting	Description	Example Value
Retry Interval	Time to wait (in milliseconds) before retrying the connection.	10000
PLC Name	Prefix added to each item name (e.g., PLC001.MyVariable.Value). Useful for distinguishing data from multiple PLCs in North caches or exports.	PLC001.
Enumeration Value	Choose to serialize enumerations as integers or text.	text
Boolean Value	Choose to serialize booleans as integers or text.	integer

Structure Filtering

Setting	Description	Example Value
Structure Name	Name of the structure to filter.	MyStructure
Fields to Keep	Comma-separated list of fields to retrieve from the structure.	MyDate,MyNumber

Example: If MyVariable is of type MyStructure with fields MyDate, MyNumber, and Value, filtering to keep only MyDate, MyNumber will generate unique point IDs:

• MyVariable.MyDate
• MyVariable.MyNumber

Item Settings

Setting	Description	Example Value
Address	The PLC address of the data to query.	MAIN.MyVariable