Siemens SIMATIC S7 System Manual page 104

Programming concepts
5.1 Guidelines for designing a PLC system
Specify the operator stations
Based on the requirements of the functional specifications, create drawings of the operator
stations. Include the following items:
● Overview showing the location of each operator station in relation to the process or
machine
● Mechanical layout of the devices, such as display, switches, and lights, for the operator
station
● Electrical drawings with the associated I/O of the CPU or expansion module
Create the configuration drawings
Based on the requirements of the functional specification, create configuration drawings of
the control equipment. Include the following items:
● Overview showing the location of each CPU in relation to the process or machine
● Mechanical layout of the CPU and expansion I/O modules (including cabinets and other
equipment)
● Electrical drawings for each CPU and expansion I/O module (including the device model
numbers, communications addresses, and I/O addresses)
Create a list of symbolic names (optional)
If you choose to use symbolic names for addressing, create a list of symbolic names for the
absolute addresses. Include not only the physical I/O signals, but also the other elements to
be used in your program.
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System Manual, V2.3, 07/2017, A5E03822230-AF
S7-200 SMART