Compare Siemens and Allen-Bradley PLC

❥ Controller

Let's start by looking at each manufacturer's controller or CPU.

From the perspective of an Allen-Bradley programmer, Allen-Bradley MicroLogix may look like a Siemens S7-1200 at first glance, with a small form factor and on-board I/O.

But in terms of processing power and memory, S7-1200 is actually more comparable to CompactLogix.

In other words, S7-1200 is more restricted in terms of additional modules. It supports up to 1 signal expansion board (also known as plug-in), 8 signal modules and 3 communication modules,

The latest CompactLogix series 5380 series can support up to 31 I/O modules (the largest controller).

Allen-Bradley CompactLogix5380

On a larger scale, Siemens provides S7-1500, which is comparable to the ControlLogix series of controllers.

The main difference between the two is that S7-1500 does not require a backplane because it is a rail mounting system.

S7-1500 also comes standard with two PROFINET ports, allowing users to separate the network and simplify the connection with other devices.

S7-1500 is also equipped with a small graphic display, which can be used for troubleshooting directly from the front of the PLC.

❥ Software

Now let's take a look at the Siemens TIA Portal software.

The first thing Siemens has to do is to program HMI and PLC from the same software package; yes, it is well known that Connected Components Workbench also allows this, but it is far from TIA Portal. (TIA Portal comes with WinCC Basic to program Siemens Basic Panel and can be upgraded to support higher-end HMI. Rockwell's Studio 5000 Logix Designer comes with View Designer – Ed for PanelView 5000 HMI)

The TIA Portal software allows users to connect to a PLC with an unknown IP address, and allows you to connect to the PLC through the accessible device options, thus simplifying the configuration of the new PLC without using utilities such as BOOTP.

When it comes to SIMATIC software, Siemens claims that they can provide the highest efficiency in the entire automation process. Their SIMATICSTEP7 allows users to configure, program, test and diagnose advanced and distributed controllers. Programmers and engineers from all over the world are familiar with the Siemens platform, making it a solid choice for any company.

Siemens also does not need other software such as RSLinx and FactoryTalk View Studio to program and set up PLC and HMI. But RSLogix 5000 and Studio 5000 need RSLinx and BOOTP and other utilities. The programming of the Allen-Bradley controller appears in the form of RSLogix5000 and the newer Studio5000. RSLogix series programming software has existed for many years and has developed into a very powerful automation tool.

❥ Programming environment

Now to your favorite topic: What is the difference between Siemens and Allen-Bradley in the programming environment?

Short answer: a lot, but a detailed introduction will be another article. Here, we will look at some of the most significant differences.

One of Siemens' advantages is that it allows users to add "unspecified CPUs" and then add I/O modules to them.

This allows the programmer to start writing code immediately before even choosing the exact CPU.

In the project tree of the TIA Portal project, we see multiple folders and icons, most of which have the same purpose as the project tree function in RSLogix 5000.

The equipment and network can be compared with RSLinx, but in my opinion it is better.

This shows the devices connected to your PLC network; man-machine interface, robot, torque box, etc.

Program blocks are places where you can add functions, function blocks, and data blocks, or in Allen-Bradley's terms, routines.

PLC tags are similar to the controller tags in RSLogix/Studio 5000. They are the location of your I/O and other tags you may want to add.

The PLC data type (you may have guessed it) is a user-defined data type.

❥ Conclusion

SIMATIC stands for Siemens Automatic. The name itself should be its role in automation and manufacturing. The SIMATIC controller has some great standard functions, including Ethernet TCP/IP simple connection and ProfinetIO communication. Profibus is included and modules can be easily added. I also think Siemens can set up new equipment more easily. Siemens is the most famous in the field of automation and PLC and provides an option for users with all performance requirements.

One of the largest PLC manufacturers in the United States is Rockwell Automation and its Allen-Bradley (abbreviated AB) series of controllers. Allen-Bradley provides controllers for all projects of different sizes. Their large-scale control system is being mentioned as a programmable automation controller or PAC. These are all made on the basis of automation projects. Their large controllers can run throughout the plant with proper design and planning. This is achieved through their ControlLogix controllers and software, GuardPLC for safety systems and SoftLogix software suites. AB also provides systems for small applications. The most popular are their MicroLogix, SLC500 and CompactLogix systems. All of these are still very powerful for the needs of almost all industries. The factory installs several of these controllers in their equipment. Allen-Bradley PLC allows users to expand the system more, but compared with Siemens, its price is higher.