How to Connect to Allen Bradley Ethernet Enabled Devices

Setting up your IP address and subnet.

Have you ever found yourself asking “Why can’t I connect to this darn Allen Bradley Controller (MicroLogix, CompactLogix, ControlLogix) or Variable Frequency Drive (PowerFlex 525, 40, 70, 700, 755) over Ethernet”?

One of the most common mistakes I see is the PC’s network adapter is setup for DHCP and/or the device’s IP address and subnet have not been configured.

Most PC’s network adapters are setup for DHCP by default and need to be this way to connect to a majority of company and home routers. To connect to Allen Bradley Ethernet enabled devices your PC’s network adapter needs to be setup to have a static IP address on the same subnet as the device.

Here is a checklist that I like to follow when I run into this situation. The PC and device(s) both need to be setup and can be setup in any order. I like to start with the PC first, and then the device(s) last.

1. First, make sure the Allen Bradley device is capable of communicating over Ethernet/IP. Just because the cable fits into the port does not mean it’s the correct one. Some of the Allen Bradley devices have RS485 ports; which is the same port that most Ethernet cables use, but it’s only used for Modbus or Serial communications not Ethernet/IP.
2. Make sure everything is powered up and all the cables are connected.
3. Make sure you have the correct software installed on your PC to communicate to the Allen Bradley Controllers (RSLinx and RSLogix 500 or Studio 5000) and Drives (Connected Components Work bench, Drives Executive, or Studio 5000).
4. Configure IP address and subnet for your PC.
   • If you’re connecting to the device either directly or through an unmanaged switch your PC must have a static IP address (most computers are defaulted to DHCP).

Windows 7 – How to set a Static IP address

1. Open Windows Start menu and click on Control Panel.
   
2. Click on Network and Sharing Center.
   
3. Click on Change Adapter Settings.
   
4. Right click on Local Area Connection and select Properties.
   
5. Select Internet Protocol Version 4 (TCP/IPv4) and click on Properties.
   
6. Select Use the following IP address to set static IP address.
   • Note: Typically this setting must be changed back to Obtain an IP address automatically to get back onto your company’s network or ant network that requires DHCP.
     
7. Once you set the IP address and Subnet, click OK and OK again in the Local Area Connection window.
8. A Static IP address has now been set!

Windows XP – How to set a Static IP address

1. Go to the Control Panel on your computer.
   
2. Click on Network Connections.
   
3. Right click the device you want to configure.
   
4. Select the Properties of the card.
   
5. This will bring up the Internet Protocol Properties. Select Use the following IP address to set static IP address.
   
6. Once you set the IP address and Subnet, click OK and then the Close button.
   
7. A Static IP address has now been set!

5. Configure IP address and subnet for your device(s)

• There are a couple ways the IP address and subnet can be setup. Most of Allen Bradley’s devices can use the BootP software utility and/or be manually setup. Manual setup is typically done through local HMI’s, rotary switches or USB ports. The manual setup is device specific and can usually be found in the devices user manual. For that reason, I’m just going to cover BootP.

BootP-DHCP Server – configure IP and Subnet address for Device(s)

1. Start the BootP-DHCP server. Go to Start > All Programs > Rockwell Software > BootP-DHCP Server.
   
2. This will open up the BootP-DHCP Server.
3. When opening it for the first time, you will be asked to configure the server. At minimum, you need to give the subnet mask. This will be the same as the computer. Then click the OK button.
   
4. With the processor powered up and connected to your computer, you should see BootP requests fill the upper screen of the server.
   
5. Select one of the requests in the Request History window and select the Add to Relation List button. This will open a window, which will automatically import the MAC address of the processor. Type in the IP address of the processor, and then click OK.
   
6. In the Request History window, the MAC address has the IP address reported back to the server. Also, below in the Relation List it will show the MAC to IP relationship. Highlight it in the Relation List in the lower pane.
   
7. By highlighting it, this enables the Disable BootP-DHCP button, to disable the processor from requesting a new IP on power cycle.
   
8. Push the Disable BootP-DHCP button. You should get the following response.
   
9. It is very important to get this! If you do not and you close this Server, especially if you are going to ControlFLASH this processor, the Flash will fail on the first polling for power. Also, if power cycles to the processor, it will lose its IP address. So it is very important to get this done.
10. Another possible response could be as follows:
    
11. If the following happens, wait one minute, click the OK button and try to disable the Bootp-DHCP again. Repeat this action until the BootP-DHCP is disabled. This is very important!
12. Now cycle power to the processor, it should be observed in the BootP-DHCP server, after clearing the history. No requests should be made in the window and the MS LED on the processor should remain solid green.
    
13. Open the Command Prompt and ping the processor.
    
14. If a request ping timeout occurs after setting the IP address, clear the DNS Resolver cache. Perform the following in a Command Prompt, type: ipconf
    
15. The IP address to the processor has been set! Create an Ethernet/IP driver in RSLinx on a local subnet. The processor will be seen in RSLinx. Functions like using ControlFLASH or going online with the processor can now be done. RSLinx will look as follows:ig /flushdnc and hit enter. Then retry the ping command.
    

Congratulations you have now configured the PC to have a static IP address and the device has been configured.   You should now be able to connect.

With multiple locations in the Bay Area and throughout in Northern California, Buckles-Smith is the leading independent electrical supplier in the region. If you want to know more about Rockwell’s BOOTP, contact Buckles-Smith and we will put you in touch with the appropriate technical specialist.