Description

Risk factors such as power outages, water damage, fire outbreaks, or lightning strikes, but also system failures or operator errors, can significantly affect the operation of a plant, as far as plant downtimes. This is where redundant systems come in.
The fault-tolerant system environment ensures protection against system failure and helps you to increase your productivity to a maximum.

Three CPUs are available for the SIMATIC S7-400H to suit different performance requirements.

SIMATIC S7-400 CPU 412-3H

CPU with a medium program memory and quantity framework

• RAM 768 KB

• 1 PROFIBUS DP-Interface*

• 2 Sync modules

• Memory Card slot

SIMATIC S7-400 CPU 414-4H

CPU for more demanding applications of the medium performance range and additional communication tasks 

• RAM 2.8 MB

• 2 PROFIBUS DP-Interfaces*

• 2 Sync modules

• Slot for additional IF-Module

• Memory Card slot

SIMATIC S7-400 CPU 417-4H

High End CPU for the upper performance range and additional PROFIBUS communication tasks 

• RAM 30 MB

• 2 PROFIBUS DP-Interfaces*

• 2 Sync modules

• 2 Sync-Module

• 2 Slots for additional IF-Module

• Memory Card slot

* One interface can be used as PROFIBUS DP or as MPI (Multipoint Interface)

Applications

Benefit

Design and function

The SIMATIC S7-400H suitable as a controller for high-availability processes, with two H CPUs of the same type; in the event of a fault, changeover takes place from the master system to the standby station. The method of event-driven synchronization supports fast and bumpless changeover to the redundant CPU in the event of a fault. It resumes processing at the point of interruption without any loss of information or interrupts.All components can be replaced during normal operation (hot swapping). When a CPU is replaced, all the current programs and data are automatically reloaded. The SIMATIC S7-400H  is suitable for high-availability processes with hot standby requirements (processes with changeover times shorter than 100 ms).

Design
The central devices can be configured in two different ways:

I/O and communication
Maximum availability is not absolutely perfect until it can be matched exactly to your needs. We offer I/O that can be configured and operated redundantly. These modules can be configured in separate racks – or also in the same rack – with a simple or redundant PROFIBUS/PROFINET connection. Maximum availability also applies to communication. Depending on the network topology, redundant connections are created to which it is possible to switch over in the event of a failure. When a failure occurs, fault-tolerant communication is automatically continued without any problems being noticeable to the user.The I/O can be connected to suit the availability requirements.The following types of connection are available:

These configurations can be mixed.

Engineering
Programming is possible, as in the case of a standard system, in all STEP 7 programming languages. The programs can easily be ported from standard systems to a redundant system and vice-versa. When the program is loaded, it is automatically distributed onto the two redundant CPUs. The functions and configurations specific to redundancy are parameterized using the S7 H-Systems option package (integrated into STEP 7 Version 5.3 or higher). The planning engineer is free to concentrate solely on controlling the process.

Diagnostics / Module replacement
Apart from the standard diagnostic functions, the following functions are also available:

Innovation

In addition, the range of controllers will be extended with the new CPU 416-5H. All CPUs will have a PROFINET interface with a 2-port switch, larger memory and an expanded quantity structure for data and function block as well as function calls.
The performance has also been improved with

Technical data

Technical data S7-400 H-CPUs

Technical data S7-400H Innovations