DMC has extensive experience programming, commissioning, and designing control panels with Allen-Bradley hardware. During the design process, we can help guide hardware selection and ensure that each component is wired properly, taking advantage of Rockwell controls features.
This blog highlights some of our favorite Allen-Bradley hardware and how to use it.
When working with ControlLogix, remember there are different communication modules depending on the model. The latest ControlLogix PLCs (5800 series) have embedded EtherNet/IP Ports where the previous designs (5700 series) did not. Because of this, an older model may need additional communication cards added, which could lead to losing a slot where you would want an additional module.
It is important to consider future expansions when choosing the rack/chassis size. Expanding to additional chasses will require another power supply, communication module, and chassis.
Further, always remember to check all IO or communication modules to make sure they are close enough to a power supply. In our designs, we try to place communication modules closest to the PLC and Power supply.
L16 through L27 CompactLogix PLCs have some embedded IO which makes them ideal for replacing MicroLogix PLCs. They also allow you to add expand their IO with additional modules. However, the L16, L18, and L19 series require 1734 IO Modules, which are POINT I/O.
The L30 and above use the standard CompactLogix 1769 series IO modules, and do not include any embedded IO.
POINT I/O modules are our favorite to use for remote IO and for PLC panel IO because of their simplicity. It is important to remember to put both the modules themselves and the base modules, in the BOM. You will wire devices into the base modules, and since they are separate items, making changes can be very easy.
It is good practice to be aware of the power consumption and the number of cards. This will help determine if you need to add a 24V power extension to your rack. I talk about similar concepts in the ET200SP IO section of my Siemens control panel design blog.
Whatever you choose to select for IO options, I would recommend using Rockwell’s Integrated Architecture Builder and ProposalWorks to help you choose your equipment. It helps us choose IO modules, and helps make sure I included the terminal bases.
Upgrading from MicroLogix or SLC500
If you are considering upgrading from MicroLogix or SLC500, there are many different things to evaluate prior to making the decision. These metrics include the number of tags, amount of programming (rungs and routines), amount of IO, type of IO, the amount of networking and networked devices, and software requirements.
Some recommendations for upgrading include:
- The Micro800 series PLCs are a great option for replacing smaller MicroLogix PLCs
- The CompactLogix smaller series with embedded IO are a great option for replacing larger MicroLogix PLCs
- The CompactLogix larger series are a great option for replacing smaller SLC500 PLCs
- ControlLogix should be used to replace large SLC500 PLCs
Learn more about DMC’s Allen-Bradley PLC Programming Services and Contact Us with any project inquiries.