How to Set a Static IP Address on a MicroLogix 1400 (With & Without BootP)

Introduction

The Allen-Bradley MicroLogix 1400 (1766-L32BWA) PLC is a widely used PLC in industrial automation, valued for its flexibility, reliability, and built-in Ethernet port. To keep your PLC connected to HMIs, SCADA systems, or other controllers, assigning it a static IP address is crucial. Without one, the PLC may rely on dynamic IPs or default to BootP mode, which can result in communication dropouts, conflicting addresses, or difficulty reconnecting after power cycles.

Many technicians run into problems when relying on dynamic addressing—such as IP conflicts, devices disappearing from the network, or the hassle of tracking down a changing IP. To avoid these headaches, this guide explains how to set a static IP on the MicroLogix 1400 using four approaches: the LCD panel, RSLogix 500 software, Rockwell’s BootP utility, and considerations for serial port communication.

Setting Static IP Using the MicroLogix 1400 LCD (Without BootP)

The easiest way to assign a static IP is directly through the MicroLogix 1400’s built-in LCD and keypad. This method doesn’t require any external software and is often the fastest solution for field technicians.

Here’s how to do it step by step:

1. Power on the controller and wait for the default I/O status screen.
2. Press the ESC button to open the main menu.
3. Use the arrow keys to navigate to Advanced Set, then press OK.
4. Scroll to ENET CFG and confirm with OK.
5. Select IP Address. If prompted, enter the password (default is usually blank).
6. Change the ENET Mode from BOOTP/DHCP to Static.
7. Enter your desired IP Address, then configure the Subnet Mask, Gateway, and optional DNS servers.

After finishing, power cycle the PLC (turn it off and back on) for the new settings to take effect. This approach is straightforward, reliable, and doesn’t depend on network conditions—making it the go-to choice for many automation engineers.

Using the RSLogix 500 Channel Configuration Menu

If you’re already programming the controller in RSLogix 500, setting the IP through the Channel Configuration menu is just as efficient. This allows you to configure network settings directly within the project and download them to the PLC.

Follow these steps:

1. Open your project in RSLogix 500.
2. In the left navigation tree, select Channel Configuration.
3. Go to the Channel 1 tab (Ethernet communications).
4. Enter your desired IP Address and Subnet Mask.
5. Uncheck the BOOTP Enable option to lock in the static IP.
6. Save your project and download it back to the controller.

Once the project is downloaded or the PLC is restarted, it will adopt the new static IP settings. This method is ideal if you’re already inside RSLogix, as it combines programming and network configuration in one workflow, saving both time and effort.

Using the Rockwell BootP Utility (and Why It Can Be Frustrating)

The Rockwell BootP utility is a legacy tool designed to assign IP addresses to PLCs based on their MAC addresses. By default, a MicroLogix 1400 without a static IP starts up in BOOTP mode, which makes this utility useful for initial configuration.

Here’s how it works:

• Connect your PLC and PC to the same network.
• Launch the BootP utility, which scans for devices and lists their MAC addresses.
• Assign an IP address to the controller and disable BOOTP so the PLC retains that static IP permanently.

While this sounds simple, BootP is notorious for being finicky. Common frustrations include:

• The PLC is not appearing in the utility due to firewalls, subnet mismatches, or multiple NICs on your computer.
• IP conflicts with DHCP servers or other devices on the network.
• The requirement to keep the utility open during configuration, which isn’t always convenient.

Because of these challenges, BootP is best used as a last resort for initial IP setup. For long-term stability, most professionals prefer the LCD or RSLogix method.

Setting the IP via the Serial Port

The MicroLogix 1400 includes an RS-232 serial port, but unlike Ethernet, it cannot be used to directly assign an IP address. Instead, the serial port is primarily used for programming, firmware updates, or recovering a PLC when Ethernet isn’t available.

While you can connect through serial to download projects or communicate with the controller, you’ll still need to use the LCD, RSLogix 500, or BootP methods to set the Ethernet IP. In short, think of the serial port as a fallback tool for access, not a way to configure network addresses.

Summary & Best Practices

There are several ways to configure a static IP on the MicroLogix 1400, but some are more efficient than others. The LCD method is simple, doesn’t require software, and works reliably in most cases. RSLogix 500 is convenient if you’re already programming the PLC, as it allows you to handle both logic and networking at once. The BootP utility can be useful for initial setups, but its quirks make it less practical for long-term use. The serial port, while valuable for communication, cannot directly assign IPs.

The best approach is to plan your IP addresses ahead of time and use either the LCD or RSLogix methods to set them. Keeping BootP as a backup option is wise, but not ideal for daily use. By choosing the right method, you’ll ensure smoother integration, avoid frustrating connection issues, and minimize downtime in your automation systems.

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