Ignition 7.3.7 with Allen-Bradley driver 1.3.5 communicates with the controller at firmware v20 but not the supplied controller at v24. Treat driver-to-controller firmware compatibility as the first check; a PLC program change or repeated network adjustments will not add support for a firmware revision the driver cannot handle.
Stop repeating fixes that cannot add firmware support
Rule out the fixes that do not address the compatibility boundary:
- Do not keep testing only against the v20 controller. That confirms the connection path can work for v20, but it does not prove the installed driver supports v24.
- Do not back-revise the supplied controller if its v24 firmware is a fixed system requirement. Using firmware v21 or later was not an available option for this installation.
- Do not assume any OPC server solves the problem. An OPC server needs a driver that can communicate with the controller’s firmware. Adding another OPC UA endpoint without a suitable Allen-Bradley driver changes the connection architecture, not the controller compatibility.
- Do not assume that installing Ignition 7.7 alone resolves it. An upgrade was attempted and problems remained. Confirm that the correct Logix driver is selected and that the new installation can communicate before treating the upgrade as a fix.
Keep the PLC program and network configuration unchanged until you have checked the driver name, driver version, and controller firmware. This avoids spending time on changes that cannot correct a driver compatibility mismatch.
Identify which Ignition driver owns the PLC connection
Ignition separates the device connection from the application’s data access. A device driver communicates with the PLC and exposes data through an OPC server; Ignition projects use that server’s data. The OPC layer does not itself translate every PLC protocol or firmware revision. The driver that talks to the controller must support the controller’s firmware.
The reported installation uses Ignition 7.3.7 and Allen-Bradley driver 1.3.5. The observed comparison is direct: the v20 controller communicates, while the v24 controller does not. The compatibility guidance in the case states that firmware v21 and later requires a newer Ignition generation, and specifically points to the Logix Driver with v21 support. Therefore, verify the actual device-driver selection rather than relying on the presence of an OPC UA server or on the Ignition version label alone.
Check the installed Gateway’s device connections and record the driver name and version shown there. Compare those details with the supported controller firmware in the matching Ignition release documentation or through official Ignition support. Do not infer v24 support merely from a statement that a driver supports v21; verify the precise firmware range for the driver release you plan to use.
Choose a route that can communicate with firmware v24
Use one of these routes, then verify its exact v24 support before changing a production connection:
| Route | What must be true | Decision |
|---|---|---|
| Upgrade Ignition | The selected built-in Allen-Bradley Logix Driver supports the controller’s v24 firmware. |
Use this route when the required Ignition release and license entitlement are available. An upgrade attempt that still fails calls for checking driver selection and the Gateway diagnostics. |
| Add a third-party OPC server | The server has an Allen-Bradley driver whose supported firmware range includes v24, and Ignition can connect to that server. | Use this route when keeping the existing Ignition installation is preferable and the external server meets the PLC compatibility requirement. |
| Back-revise controller firmware | The system owner permits a firmware change and the selected revision is compatible with the application. | The installation described rules this route out because the supplied controller must remain at its newer firmware. |
Ignition already includes an OPC UA server, but that does not automatically make an external OPC server redundant. The external server is useful only if its own PLC driver supplies the missing controller support. Kepware is one named option; verify with its product documentation or sales/support channel which package and release support Rockwell firmware v24. Do not select a specific server release based on the older example version mentioned in the discussion.
Licensing is separate from technical compatibility. Check the current Ignition license and support entitlement with Inductive Automation or the original seller before budgeting for an upgrade. Likewise, confirm the external server’s license and driver package before purchase.
Configure the selected driver and prove the device connection
Make one controlled change at a time. For an Ignition upgrade, select the Allen-Bradley Logix Driver identified as supporting the required firmware. For a third-party route, install and configure its Allen-Bradley driver first, then add that server to Ignition as an external OPC connection.
- Record the controller firmware, Ignition version, installed Allen-Bradley driver name/version, and current device-connection status.
- Confirm in the driver’s compatibility documentation that its supported firmware includes v24. For a third-party server, verify both the specific Rockwell driver package and server release.
- Configure the driver to connect to the controller using the project’s existing network path and controller identity. Use the device status and Gateway diagnostics to check whether the driver establishes a connection; do not use tag quality alone to diagnose the first connection attempt.
- If using an external OPC server, verify that it can browse or read a known controller item locally. Then configure Ignition to connect to that OPC server and browse the same item through Ignition.
- After the connection works, migrate or test the project’s tag subscriptions against the selected server, then document the final driver and firmware pairing.
Keep the new server path distinct from Ignition’s built-in device driver while testing. That lets you tell whether a failure occurs between PLC and driver or between OPC server and Ignition.
Use the symptoms to isolate the failing layer
Compare the symptom with the layer that can produce it. The v20-versus-v24 behavior is the strongest initial clue, but the status and diagnostics decide whether the selected remedy worked.
| Symptom | Likely cause to check first | Next check |
|---|---|---|
| v20 communicates; v24 does not | Driver firmware support or selection | Confirm the installed driver name/version and its documented v24 range. |
| Ignition 7.7 was installed but v24 still fails | Wrong Allen-Bradley driver, incomplete configuration, or another device-connection fault | Check whether the Logix Driver is selected; read the Gateway device diagnostics. |
| External OPC server reads the PLC, but Ignition does not show the data | External OPC connection or Ignition-side browsing/tag configuration | Test the external OPC connection and browse the same item in Ignition. |
Designer launch opens a .jnlp file instead of starting Designer |
Linux desktop file association or Java Web Start launch handling, separate from PLC communications | Resolve the JNLP launch association independently; do not treat it as evidence that the PLC driver is failing. |
Do not use successful Designer launch as proof of PLC compatibility, or a JNLP launch problem as a reason to replace a working PLC driver. These are separate paths: the Designer must launch for project editing, while the Gateway’s device driver handles PLC communications.
Verify controller data through every connection layer
After changing drivers, verify connection status from the PLC outward. A green project screen alone does not prove that the controller data path is sound.
- Confirm the selected driver reports a connected or healthy device state in the Gateway.
- Read a known, stable controller item at the driver or OPC server layer. Check the value and quality/status, not only whether the item appears in a browse list.
- For an external server, confirm the same item reads correctly from its OPC endpoint, then confirm Ignition can browse and read that item through its external OPC connection.
- Test representative project tags and confirm their values and quality remain valid after the connection is established. Compare against the controller or an independent engineering view where available.
- Save the working firmware, Ignition release, driver release, and connection route in the site configuration record so a later maintenance change does not silently restore an incompatible path.
If device status fails before OPC browsing, stay at the PLC-driver layer and inspect the connection diagnostics. If the external server reads correctly but Ignition cannot browse it, troubleshoot the OPC connection between the server and Ignition instead of changing PLC firmware or logic.
FAQ
Why does Ignition 7.3.7 communicate with v20 but not v24?
The installed Allen-Bradley driver may support the older controller firmware but not the v24 controller. Check the driver name and its documented firmware range before changing PLC logic or network settings.
Why did upgrading Ignition to 7.7 not fix the PLC connection?
Check that the device uses the Allen-Bradley Logix Driver identified for newer firmware, then inspect Gateway device diagnostics. An upgrade alone does not confirm that the correct driver is selected or configured.
Do I need Kepware if Ignition already has an OPC UA server?
Only if you need a separate PLC driver that supports the controller firmware. Verify that the external server’s specific Allen-Bradley driver supports v24, then connect Ignition to that server as an OPC client.
Can any OPC UA server connect Ignition to an Allen-Bradley PLC at v24?
No. The OPC UA server must include a PLC driver that supports the required firmware, and Ignition must be able to connect to that server. Test a known controller item at both the server and Ignition layers.
When should I stop troubleshooting and contact official support?
Stop before purchasing or deploying a new server if its v24 support, license, or Ignition integration path remains unclear. Escalate with the controller firmware, Ignition and driver versions, Gateway diagnostics, and the layer where the test fails to Inductive Automation or the selected server’s official support channel.