---
title: "Connecting to ControlLogix"
---

# Connecting to ControlLogix

> :::note
> This driver supports ControlLogix firmware up to version 20.18.
> :::

## Connect to a ControlLogix Device

This driver requires the OPC UA module to be installed and enabled. If the module is missing or disabled, the device will fault with a “Missing Dependency” error on the **Platform** **System** > **Modules** page.

1. On the Gateway, go to **Connections** > **Devices** > **Connections**.

    ![](../../devices-connections.png)

2. Click **Create Device Connection +**.

3. Select **Allen-Bradley ControlLogix (Legacy)** and click **Next**.

    ![](select-controllogix.png)

4. On the **Configure Device** screen, enter the required fields:

   * **Name**: CLX
   * **Hostname**: The IP address of the PLC (e.g., 10.20.4.50)

   ![](controllogix-settings.png)

5. Click **Create Device Connection**.

The device will be listed now on the Connections page. The status will initially show Disconnected, but will move to a Connected state.

![](controllogix-connected.png)

## Device Connection Settings

### General

| Name | Description |
|------|-------------|
| Name | A user-defined name for the device. This name appears in OPC item paths and the Devices list. Name must begin with an underscore or a letter, and cannot include special characters. |
| Description | An optional description to help identify the device. |
| Enabled | When selected, the device is active and available for use in the system. |

### Connectivity

| Name | Description |
|------|-------------|
| Hostname | IP address of the Ethernet module (e.g., 1756-ENET) used to connect to the ControlLogix processor. |
| Local Address | IP address of the local network adapter to bind to. Leave blank to auto-select. |
| Timeout | Timeout in milliseconds for a request to receive a response from the device. |
| Connection Path | Used to define a route to the ControlLogix or downstream PLC-5 processor. See [Allen-Bradley Connection Paths](../allen-bradley-ethernet.md#allen-bradley-connection-paths) for more information. |

### Advanced

| Name | Description |
|------|-------------|
| Disable Automatic Browse | Disables automatic browsing of the tag tree. |
| Show String Arrays | Displays string arrays from the device if supported. |
| Status Request Poll Rate | Frequency in milliseconds for polling the device status. |
| Slot Number | The zero-based slot number of the ControlLogix processor in the chassis. |
| Max Concurrent Requests | Number of simultaneous requests the driver sends to the device. Higher values may improve throughput but can overload the PLC. |

### Supported Connection Methods

This driver supports ControlLogix 5500 devices connected through a 1756-ENET/A or 1756-ENET/B module.

### Considerations for ControlLogix Settings

When the ControlLogix processor **External Access** setting for a tag is set to `None`, the tag information is not returned to Ignition during reading of tag information.

Using RSLogix 5000, change the External Access setting to either `Read Only` or `Read/Write` for the tag to show in the Ignition browse results.

![](external-access.png)