Ignition CompactLogix Idle and No Tags: Fix via OPC Browser

Here is the symptom. You added the controller in the Gateway under Config → OPC UA → Device Connections → Create new Device... → Allen-Bradley Logix Driver. The device shows as enabled. The status reads Idle. In the Designer, the project's Tags folder is empty.

This is usually not a communications fault. Ignition does not create project tags on its own. You have to import them. Until you do, the driver has nothing to poll.

Skip These Fixes: They Waste Time

These are the first things most people try. None of them fixes an empty tag tree.

• Deleting and recreating the device connection. A second identical device does exactly what the first one did. If the IP and driver type were right the first time, recreating the device changes nothing.
• Switching driver types at random. Only change the driver after you confirm the controller firmware and see that the browse fails (see below). If the browse returns controller tags, the driver is correct.
• Hunting for an auto-import or "sync tags" setting. No such setting exists for this workflow. Ignition tags are more than PLC data. The system has memory, expression, query, derived, and reference tags. The platform treats OPC tags as one tag type that you place on purpose.
• Dragging the entire controller into the tag tree to "get it working". This fills the tag tree and loads the controller's communication capacity. Every imported tag gets polled. Thousands of them at a fast rate slow the whole connection down. Don't do it.

Why the Driver Sits Idle and the Tag Tree Stays Empty

The Gateway device connection and the project tag tree are separate layers:

• Device connection (Gateway): the driver session to the controller. It exposes the controller's tag database through the Gateway's OPC UA server.
• Tag provider (Designer): the tags your project actually uses. An OPC tag here is a subscription that points at an address in the OPC server.

The driver polls only the items that tags subscribe to. With zero OPC tags in any provider, nothing subscribes. The device can sit enabled with no active traffic, so Idle with no error means "nobody is asking for data yet". A failure looks different: the device status shows a connecting or faulted state, or the OPC browse returns nothing.

Start Here: Prove the Link With a Browse

The OPC browse tells you whether this is a comms problem or a configuration problem. Do it before you touch the network.

1. Open the Designer and connect to the Gateway that holds the device.
2. Open the OPC Browser (Tag Browser → the OPC browse option).
3. Expand the Ignition OPC UA server, then Devices, then your device name.
4. Watch what comes back.

Import Tags Into a Folder the Right Way

If the browse shows the controller's tags, the connection works. Build the tag tree now.

1. In the Tag Browser, right-click the tag provider and create a folder structure that matches your application: by machine, by area, or by line. Do not use one flat folder.
2. In the OPC Browser, expand the controller tags down to the members you actually display, trend, alarm, or write.
3. Drag only those tags or structures into the target folder. Ignition creates OPC tags that point at the device addresses.
4. Put tags into tag groups by need. Use fast scan only for operator-interactive values. Put slow process values, setpoints, and diagnostics in slower groups.
5. Save the project. The device status changes from Idle once the new subscriptions start polling.

Pitfall: dragging a whole controller-scope array or a large UDT instance brings every member with it. Check how many tags you are about to create before you drop them.

Fix the Network Path When the Browse Fails

Work through these checks in order. The early ones are fast and catch most failures.

1. Controller firmware. Read it in the controller properties in Studio 5000/RSLogix 5000, or on the Ethernet module's web page. Compare it against the firmware range that Inductive Automation's driver documentation lists for the Logix driver. Older controllers need a different driver option in the same Create new Device... list.
2. Direct or routed connection. A CompactLogix with an embedded Ethernet port is addressed by its IP directly. If the Gateway reaches the controller through another module or another controller, the device needs a connection path through that bridge. A missing or wrong path produces a device that connects but cannot browse.
3. Same subnet. Compare the Gateway server's IP and mask with the controller's. If they are on different subnets, a router or Layer-3 switch must route between them, and both sides need a correct default gateway. From the Gateway machine, ping the controller as a first check. Treat ping as necessary but not sufficient, because ICMP can pass while EtherNet/IP is blocked.
4. NAT and firewalls. Look for NAT devices, managed switches with ACLs, OS firewalls, and security appliances between the Gateway and the controller. If a NAT sits in the path, enter the translated address in the device configuration, not the controller's local IP.
5. Duplicate IPs. An IP conflict with another node gives intermittent connections. Unplug the controller and ping the address. If something still answers, you have a conflict.

Verify the Tags Are Live

• Gateway: the device status reads connected, not Idle, once tags subscribe.
• Designer: every imported tag shows Good quality, and its value matches the value in Studio 5000 online.
• Change test: toggle a non-critical bit or change a test value in the PLC. The Ignition tag should follow within its tag group's scan interval.
• Load check: in the Gateway status pages for the device, look at request counts and overload indicators. If the device reports overload, move tags to slower groups or remove unused ones.

FAQ