How to connect to an Allen Bradley Micro800 PLC that has DHCP enabled

In this lesson we show you how to connect to an Allen Bradley Micro800 PLC with the Connected Components Workbench Software when DHCP is enabled.

The Allen Bradley Micro 820’s default IP Address configuration is set to DHCP.  The easiest way to set the IP address in this situation is with our IP Explorer.  With Allen Bradley’s Boot-DHCP Server becoming less reliable with later versions of Windows, we no longer recommend it.  But if you don’t have our IP Explorer then you can still get online with the PLC.

1.  To begin, plug your Ethernet cable from your PC directly into your PLC.  You could use an Ethernet switch here but this is a basic way to make a sure connection.  Since there is not DHCP server in our network configuration, both the PLC and PC will assign themselves an IP address of 169.254.XXX.XXX with the last two octets being random.  If you PC is configured for a static IP address, the first two octets must be 169.254 to connect to a DHCP configured device.  See our article on DHCP basics for more details.



2.  Now open RsLinx and go to Communications > Configure Drivers...



3.  Look through your Configured Drivers and see if you see AB_ETHIP-1.  If not, click the drop down under available driver types and select “Ethernet/IP Driver”, then click the “Add New” button.



4.  I’m not usually picky about naming devices but leave the new driver name as “AB_ETHIP-1” and click “OK”, it will make connecting to PLCs a little easier later on.



5.  The Windows Default will do for most applications but you can click the specific adapter that you are connecting to the PLC with if you wish.



6.  Now close the Configure Drivers dialog select Communications > RSWho.  Navigate to the AB_ETHIP-1 driver you just created and you should see your Micro 820 PLC.  If you don’t then chances are your PLC’s IP has already been configured.  You will need an offline copy of the program or our IP Explorer to discover the PLC’s IP address.



7.  Now go to Connected Components Workbench and on the startup screen you will see Discover. Click it



8.   Navigate to your PLC under the AB_ETHIP-1 driver you just created.  The CCW software will now upload the PLC program to your PC.



9.  Here you can change the Ethernet configuration of your PLC.



10.  Here you can view the ladder logic program of your PLC.



Next Steps

Go to the Allen Bradley Connected Components Workbench CCW Micro 800 Lesson series to select your next lesson.  There are also many other Lesson Series on PLC Programming and Industrial Automation.