The SIPLUS S7-300 CPU 315-2 DP is a CPU with medium to large program memory and PROFIBUS DP master/slave interface. It is used in installations which have distributed automation structures in addition to a centralized I/O.

It is often used as the standard PROFIBUS DP master in SIMATIC S7-300. The CPU is also used as distributed intelligence (DP slave).

It has been optimized in terms of its quantitative framework for using SIMATIC Engineering Tools, e.g.,:

• Programming with SCL
• Sequence control programming with S7-GRAPH

In addition, the CPU offers an ideal platform for simple technology tasks implemented in software, e.g.,:

• Easy Motion Control
• The solution of closed-loop control tasks with STEP 7 blocks or the runtime software Standard/Modular PID Control

Extended process diagnostics can be achieved by using SIMATIC S7-PDIAG.

• Password protection;
  a password concept protects the user program from unauthorized access.
• Block encryption;
  the functions (FCs) and function blocks (FBs) can be stored in the CPU in encrypted form by means of S7-Block Privacy to protect the know-how of the application.
• Diagnostics buffer;
  the last 500 error and interrupt events are stored in a buffer for diagnostic purposes, of which 100 are stored retentively.
• Maintenance-free data backup;
  the CPU automatically saves all data (up to 128 KB) in case of a power failure so that the data are available again unchanged when the power returns.

Parameterizable properties

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

• General;
  definition of the name, plant identifier and location ID. Parameter assignment of the multi-point interface MPI: Determining node addresses.
• Startup;
  definition of the startup characteristics of the CPU and the monitoring time
• Synchronous cycle interrupts;
  setting of DP master system, process image partition number, and delay time
• Cycle/clock memory;
  specification of the maximum cycle time and load. Setting of the clock memory address.
• Retentivity;
  setting retentive areas
• Clock interrupts;
  setting of start date, start time and periodicity
• Watchdog interrupts;
  setting of periodicity
• System diagnostics;
  determining handling and scope of the diagnostic alarms
• Clock;
  setting the type of synchronization in the AS or on the MPI
• Protection level;
  specifying the access rights to program and data
• Communication;
  reservation of connection resources
• PROFIBUS DP master/slave interface;
  User-oriented address allocation for distributed I/O. Parameterizing the operating mode and configuring the transfer areas in the case of PROFIBUS DP. Parameterizing the time synchronization

Display and information functions

• Status and error indications;
  LEDs indicate hardware, programming, time, I/O, battery and bus errors, and operating statuses such as RUN, STOP and start-up.
• Test functions;
  the PG is used to indicate signal states 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.