• Block protection:
  In addition to the keyswitch, a password concept protects the user program from unauthorized access. User blocks can also be protected by an encryption mechanism.
• Integrated HMI services:
  For HMI devices, the user only has to specify the source and destination for the data. They are then automatically transported by the system on a cyclic basis.
• Integrated communication functions:
  
  • PG/OP communication
  • Extended communication (standard and high-availability)
• Master-spare switchover programmed by user

Parameterizable attributes

With the STEP 7 "Hardware Configuration" tool and the installed S7-400H option package, the properties and behavior of the S7-400H including the CPUs can be parameterized, e.g.:

• MPI multi-point interface:
  
  • Determination of node addresses
  • Start-up/cyclic response
  • Determination of maximum cycle time and communication load
• Address assignment:
  Addressing of I/O modules
• Retentive areas:
  Determination of number of retentive bit memories, counters, timers, data blocks and clock memories
• Protection level:
  Specifying the access rights to programs and data
• System diagnostics:
  Determination of handling and scope of diagnostic alarms
• Cyclic interrupts:
  Setting of periodicity
• Configuration of H stations

Display and information functions

• Status and error LEDs:
  LEDs indicate, for example, internal and external faults and operating statuses such as RUN, STOP, startup and "Master" operating mode as well as redundancy errors and test functions.
• Test functions:
  The PG is used to indicate signal states during program execution, to modify process variables independently of the user program, to output the contents of stack memories, to execute individual program steps, and to block program sections.
• Information functions:
  The PG can be used to obtain information about the memory capacity and operating mode of the CPU and the current loading of the work and load memory.