• Password protection;
  a password concept protects the user program from unauthorized access.
• Diagnostics buffer;
  the last 500 error and interrupt events are stored in a buffer for diagnostic purposes.
• Maintenance-free data backup;
  all data is automatically backed up by the CPU if the voltage is interrupted and is available unchanged after the voltage has been reconnected.

Parameterizable properties

The S7 configuration as well as the properties and response of the CPUs can be parameterized using STEP 7:

• Multi-Point Interface (MPI);
  determination of node addresses.
• Start-up/cycle time behavior;
  definition of maximum cycle time and loading.
• Clock memory;
  setting of addresses.
• Protection level;
  definition of access rights for program and data.
• System diagnostics;
  definition of handling and scope of diagnostic messages.
• Watchdog interrupts;
  setting of periodicity.
• Time-of-day interrupts;
  setting of start date, start time, and periodicity.
• PROFIBUS DP master/slave interface;
  user-oriented address allocation for distributed I/O.

Display and information functions

• Status and error indications;
  LEDs indicate hardware, programming, time, I/O or bus errors and operating statuses such as RUN, STOP, start-up.
• Test functions;
  the PG is used to indicate signal status during program execution, to modify process variables independently of the user program and to output the contents of stack memories.
• Information functions;
  the PG can be used to obtain information about the memory capacity and operating mode of the CPU, the current loading of the work and load memory, current cycle times and diagnostics buffer content in plain text.

Integrated communication functions

• PG/OP communication
• Global data communication
• S7 basic communication
• S7 communication
• Open communication by means of TCP/IP
• PROFINET CBA
• Web server
• Data record routing

Communication

Safety-oriented and standard communication between the central controller and distributed stations takes place over PROFIBUS DP and/or PROFINET. The specially developed PROFIsafe profile supports the transfer of user data for the safety functions within the standard data message frame. Additional hardware components, e.g. special safety buses are not required. The necessary software is either integrated in the hardware components as an expansion of the operating system or loaded into the CPU later as a certified software block.

Mode of operation

The safety functions of the F-CPU are included in the F program of the CPU and in the fail-safe signal modules. The signal modules monitor the output and input signals by means of discrepancy analysis and the injection of test signals. The CPU checks the proper operation of the controller by means of periodic self-tests, command tests and logic-based and time-based program execution checks. Furthermore, the I/O is checked using requests for signs of life. If an error is diagnosed in the system, the system will be placed in a safe state. An F runtime license is not required to operate the CPU 315F-2 PN/DP.

Programming

The CPU 315F-2 PN/DP is programmed in the same manner as the other SIMATIC S7 systems. The user program for non-fail-safe plant sections is created using familiar programming tools, e.g. STEP 7.

Option packages SIMATIC S7 Distributed Safety (Classic) and SIMATIC Safety Advanced V12 (TIA Portal V12)

The STEP 7 option packages “SIMATIC S7 Distributed Safety” (Classic) or SIMATIC Safety Advanced V12 (TIA Portal V12) are required for programming the safety-related program sections. The packages contain all the functions and blocks required to create an F program.

The F program with the safety functions is connected in F FBD or F LAD or using special function blocks from the F library. Use of F FBD or F LAD simplifies configuration and programming of the system and also acceptance testing thanks to the cross-system uniform presentation form. The programmer can concentrate on configuration of the safety-related application without the need to use additional tools.