Connecting to a OPC Server


    The OPC Server Connections page is displayed.
  2. Click on the Create new OPC Server Connection link.
    The Discover OPC-UA Endpoints page will appear.




    Ignition can connect to its own OPC-UA server's endpoint by using localhost and the default port of 4096, or a hostname can be used:



  6. Select a Security Policy and Message Security configuration to use when connecting to the endpoint. Basic128 SecurityPolicies and SignAndEncrypt MessageSecurity are more secure than None. If available, Basic256 should be selected. Once an endpoint configuration has been selected, click the Next button as shown in the above image.

  7. On the New OPC UA Connection Settings page, give the connection a name. Some OPC-UA servers may require a Username and Password, but this is not always the case. Check with the OPC-UA server's documentation for more details. By default, Ignition's OPC-UA server requires the following credentials:


    Ignition is now connected to the OPC-UA server.  



OPC-UA Server Properties


NameA name used to identify this connection.
DescriptionShort description of this connection.
EnabledDisable the connection to the OPC server.


Change Password?Enable this property to change the configured password.
PasswordEnter password
PasswordRe-type password for verification.


Max References Per Node

Configures the number of references per node. A "node" in this case is any item inside of a UA server, so items like tags and folders would qualify as a node, while a References is simply a reference to another node. This setting is useful in situations where the address space is completely flat, so a large number of adjacent nodes could potentially run into a maximum message size. In these cases increasing the value of this property can be useful.

However, most systems will not need to change this setting. Defaults to 8,192 references.

Secure Channel Re-authentication Enabled(default: true)

Redundancy Settings

Backup Host OverrideWhen specified, if the endpoint address returned by the Backup OPC server has a different IP address or hostname than the discovered endpoint, the overridden value will be used. Expects just an IP address or hostname. Example:
Failover EndpointThe endpoint of the failover server.
Example: opc.tcp://
Failover ThresholdThe number of retry attempts before the failover connection is used. The default is 5.



How do I determine the Endpoint for my backup? 


Failover Versus Backup Properties 

The Failover properties should be used when a single Ignition Gateway needs to connect to a pair of redundant OPC-UA servers. The failover OPC-UA server will be used in the event the primary OPC server goes down.  To enable failover, set the Failover Enabled property to true, and specify the Failover Endpoint. The Failover Threshold can be adjusted if desired. Note: Failover events are "sticky." That means once control has moved to a backup OPC-UA server, it stays there until that server fails.



OPC Quick Client

You can access the OPC Quick Client from under the OPC Connections section of the Ignition Gateway Configure section. It allows for quick, simple testing of any devices connected to the server.
You can browse by expanding tree nodes and read/write to Tags by clicking on the [r] and [w] buttons next to those Tags.
Subscriptions can be made by clicking on the [s] button. For each individual subscription, you can click on the SET button  and it will automatically refresh subscriptions and show live value changes (if there are any).



Ignition OPC-UA Server

You can see the following OPC-UA Server Settings by going to the Configure section of the Gateway, and then choosing OPC-UA Server > Settings.


user: opcuauser
password: password


Endpoint Address



Expose Configured Tags 

Expose Tag ProvidersIf enabled, Ignition Tag providers will be exposed through the OPC-UA server, allowing third party clients to access the Tags configured in the system. By default, the check box is not selected or False.
Audit ProfileIf enabled, writes to exposed Tags will be audited to the selected profile.


Read Only When Inactive Operate in read-only mode when this node is the inactive node of a redundant pair.


A Frequently Asked Question

How to I get data from my PLC?


  1. Add a device, see Connecting to a Device.
  2. Add some tags, see Creating Tags.


Brief summary of device connection in Ignition

  • Ignition can only connect directly to devices over Ethernet. 
    • Modbus - The Modbus driver connects to any ethernet enabled device that uses the Modbus protocol.

Adding a Device to Ignition

Ignition Supported OPC-UA Device


  1. Click "Add a device..."



Adding Connection to 3rd Party OPC Server via OPC-UA


Adding Connection to 3rd Party OPC-Server via OPC-COM


Adding Tags for Allen Bradley Devices

Tags are how Ignition represents your PLC Tags. You create Tags in the Ignition Designer and then you can use these Tags to store history or display PLC data in your projects.
For the most part, Allen Bradley devices support browsing of Tags in the PLC. There are a few exceptions, like the MicroLogix 1200/1500 for which you have to manually address your Tags. For now, we will focus on creating Tags from devices that support browsing.

  1. Open the Ignition Designer.
  2. Drag desired Tags from the OPC Browser to the Tag Browser as described here: Creating Tags (if you don't know what Tag Provider means don't worry, merely drag them into the Tags folder). You should now see some Tags in the Tag Browser that show the current values of the respective Tags in your PLC. Don't stop here. You should read through the related links below so you can learn more about Tags and how they work.

Why am I getting Endpoint errors?

If you are getting an "UaException: status=Bad_TcpEndpointUrlInvalid" error, it is because an OPC UA connection Endpoint can only contain certain characters. Most likely, you have an underscore in the Endpoint Address. See the oracle docs for more information on what exactly can be used in the URI.