When it comes to programmable logic controllers (PLCs), Siemens offers two main options: the SIMATIC S7-1200 and the SIMATIC S7-1500. Both PLCs have their strengths and weaknesses, and choosing between them will depend on the specific needs of your project. In this article, we will take a closer look at the similarities and differences between the SIMATIC S7-1200 and the SIMATIC S7-1500, to help you make an informed decision.
Although it likely overlaps with the micro800 and a tiny compactlogix for memory, think of the S7-1500 as the ControlLogix and the s7-1200 as the CompactLogix. Despite the S7-1500 having some additional functionality, they are essentially identical. The s7-1500 is speedier and has greater work memory (RAM). It contains PLC-based alerting capabilities and built-in HW diagnostics. Both come equipped with Profinet capability, and programming will be done through Ethernet.
There are several distinct form factors for the 1500s in terms of HW. “Normal” s7-1500 is ET200MP, which has a built-in display in the CPU. Slice IO interface module-style ET200SP CPUs are available. An IP65 IO rack can house ET200PRO CPUs. Although you occasionally come into a problem where some external tool won’t operate with multiple form factors, like PLCSIM, they all program similarly. Although different s7-1200 CPUs let varied numbers of IO modules be attached, s7-1200s are only available in HW flavor.
Processor
One of the main differences between the S7-1200 and the S7-1500 is the processor. The S7-1200 uses a Cortex-M3 processor, while the S7-1500 uses a Cortex-M4 processor. The S7-1500 has a more powerful CPU with faster processing speeds, which makes it better suited for larger and more complex systems.
I/O Points
Another important difference between the two PLCs is the number of I/O points. The S7-1200 has a maximum of 128 I/O points, while the S7-1500 can have up to 2048 I/O points. This makes the S7-1500 more suitable for larger and more complex systems that require more inputs and outputs.
Ethernet Connectivity
The S7-1500 has built-in Ethernet connectivity, while the S7-1200 requires an additional communication module to enable Ethernet connectivity. This means that the S7-1500 is more flexible and can be easily integrated into a networked system, while the S7-1200 may require additional hardware and configuration.
Programming
Both PLCs are programmed using Siemens software, but they use different software. The S7-1200 uses Siemens’ TIA Portal software, while the S7-1500 uses the Siemens S7-1500 software controller. Both software programs are user-friendly and intuitive, but the S7-1500 software controller is more advanced and offers more features than the TIA Portal.
Step 7 Basic is used to program the S7-1200 whereas Step 7 Professional is needed for the S7-1500. Both are on TIA Portal and have the same appearance and feel, but Pro is 10 times more expensive. PLCSIM is included in both Basic and Professional to simulate code without uploading it to a real device.
Cost
Cost is always an important factor to consider when choosing a PLC. The SIMATIC S7-1500 is more expensive than the SIMATIC S7-1200, and it may be overkill for smaller and simpler systems. On the other hand, the S7-1200 is a more cost-effective option for smaller systems, but it is less powerful and has fewer I/O points.
Motion
The way that motion is handled varies slightly. While S7-1200 motion is mostly dependent on steppers, S7-1500 motion is based on VFD/Servos. The setup choices are altered but the programming remains the same.
Memory
For the project to be stored, 1500 needs a memory card. Although s7-1200s comes with some built-in load memory, you can always extend it with memory cards. Both parties can utilize the memory cards for purposes like data recording to a CSV file.
In conclusion, the SIMATIC S7-1200 and SIMATIC S7-1500 are both powerful PLCs that offer different features and capabilities. The S7-1200 is a more cost-effective option for smaller systems, but it is less powerful and has fewer I/O points. The S7-1500 is more powerful and versatile, with more memory, I/O points, and built-in Ethernet, but it’s also more expensive and may be overkill for smaller and simpler systems. Ultimately, the choice between the two will depend on the specific needs of your project.
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