• Block protection:
  A password concept also protects the user program from unauthorized access
• Integrated HMI services:
  The user only has to specify the source and destination of the data with HMI devices. The data are then transported cyclically and automatically by the system.
• Integrated communication functions:
  • PG/OP communication
  • Global data communication
  • S7 standard communication
  • S7 communication

Programmable properties

The STEP 7 tool "Hardware configuration" can be used to parameterize the properties and response of the S7-400 including the CPUs, e.g.

• Multipoint interface MPI:
  • Definition of node addresses
  • Startup/cycle behavior
  • Stipulation of the maximum cycle time and communication load
• Address allocation:
  Addressing of I/O modules
• Retentive area:
  Definition of the number of retentive bit memories, counters, timers, data blocks, and clock memories
• Size of the process image, local data
• Length of the diagnostics buffer
• Protection level:
  Definition of access authorizations to program and data
• System diagnostics:
  Definition of the handling and scope of diagnostics messages
• Timed interrupts:
  Setting of periodicity

Display and information functions

• Status and fault indicators:
  LEDs indicate internal and external faults and operating modes such RUN, STOP, restart, test function, etc.
• Test functions:
  The PG can be used to display signal states in program execution, modify process tags irrespective of the user program, read out the contents of stack memories, run separate program steps and inhibit program components.
• Information functions:
  The PG can be used to provide the user with information about the memory capacity and operating mode of the CPU, and the current utilization of the working and load memories.