Siemens lost the battle of Logic Controllers. Allen Bradley the best option.

Below are some Allen Bradley vs Siemens PLCs comparisons: 1. Pricing is not always a key consideration, but still a factor. Siemens Safety PLCs are less expensive. Rockwell's Allen Bradley least expensive safety PLC, the Compact GuardLogix, is at a higher entry cost. 2. Siemens PLCs have built-in safety/standard communication ports. Rockwell requires additional cards (Ethernet/IP, DeviceNet.) 3. Siemens does not require a rack or Siemens power supply for the rack, any external 24VDC works. Allen Bradley requires both a Allen Bradley Rack and a Allen Bradley power supply. 4. Siemens supports up to 2 safety runtime groups. This allows the user to implement the safety system at two different time cycles and priorities. For those that find that they have a few safety functions that require a very fast response time within a larger system that doesn't need such a fast response, Siemens easily supports this system. Rockwell has one safety task and cannot establish two priority groups. 5. Rockwell charges for technical support based on the amount of installed hardware. Siemens provides standard technical support at no charge. 6. Siemens supports writing to standard outputs from the safety program. Rockwell does not.This is not a huge item, but if it makes sense to do something such as turn on an indicator light when a particular E-Stop is pressed (or some other function), Siemens supports putting both of these logic elements on the same network in the Safety logic. Rockwell would need to write to the safety output in the safety code, and the standard output somewhere in the standard code. 7. Rockwell provides the safety functions standard with the RSLogix software. With Siemens, Distributed Safety is an add on package with a separate charge. 8. Rockwell's development is perceived by some as intuitive and easy to use.Siemens is perceived as extremely capable, but developed more for engineers than for maintenance and support personnel.