Documenting some observations from my first use of the Siemens 1214.
First, regarding the wiring, this Siemens model supports both NPN and PNP input configurations. I previously thought that Siemens inputs could only be configured as PNP. The common terminal for its inputs is marked as M, which led me to believe it could only be connected to negative, but that is not the case.
Next, I used two analog inputs, utilizing the built-in analog ports of the CPU, which are fixed at 0-10V and cannot be changed. Therefore, it is crucial to match the sensors accordingly; otherwise, you will need to find a way to convert the signals.
Finally, in terms of programming, the registers M, MB, MW, and MD represent different data types but are all M registers. For instance, if you use M1.0 and then use MD0 to store data, there will be a conflict. Thus, it is essential to plan the usage of registers in advance to avoid conflicts. Additionally, the registers that retain data after power loss start from MB0, so you need to plan the required non-volatile memory for parameter storage. As for writing the program, it mainly comes down to habit, as the device operations involving cylinders and motors are not complex, making it difficult to assess the programming difficulty. I will document further when I use new features in the future.