During the design process, the proper controller is needed to be chosen, therefore there are some criteria from which the choice of the PLC will be based on:
- Number of logical inputs and outputs
- The memory size of the controller from which the program will be installed on.
- The number of special I/O modules that could be used for a large number of applications.
- The strength of communication in terms of serial and network connections, that allow the PLC to be programmed.
- Availability of programming software and the ease of use of debugging and programming.
As per Dr. Nader’s recommendation, Siemens PLCs is reviewed for this specific application, due to its ease of use and its availability worldwide, in addition to the availability of its own programming software the Simatic S7.
Both Siemens S7-1200 and S7-1500 are great PLCs, nevertheless; S7–1500 are commonly used for medium to large applications while S7–1200 PLCs are commonly used for small to medium applications. Moreover, the S7-1200 is almost one-third the price of the S7-1500, allowing us to cut costs on a large scale and yet yield reliable outputs.
The S7-1200 model that will be used has the specifications given in the table below:
Selected PLC Specifications
