Overview Of The Parameters For The S7-400H Cpus - Siemens SIMATIC S7-400H System Manual

5.10

Overview of the parameters for the S7-400H CPUs

Default values
You can determine the CPU-specific default values by selecting "Configuring Hardware" in
STEP 7.
Parameter blocks
The reactions and properties of the CPU are set at the parameters which are stored in system
data blocks. The CPUs have a defined default setting. You can modify these default values
by editing the parameters in the hardware configuration.
The list below provides an overview of the configurable system properties of the CPUs.
● General properties, such as the CPU name
● Startup
● Cycle/clock memory, for example the cycle monitoring time
● Retentivity, i.e. the number of memory markers, timers and counters retained
● Memory, such as local data
● Assignment of interrupts (hardware interrupts, time delay interrupts, asynchronous error
● Time-of-day interrupts, such as start, interval duration, priority
● Cyclic interrupts, for example priority, interval duration
● Diagnostics/clock, for example time-of-day synchronization
● Levels of protection
● Fault-tolerant parameters
S7-400H
System Manual, 09/2007, A5E00267695-03
Note: If you change the RAM allocation by modifying parameters, this RAM is reorganized
when you download system data to the CPU. The result of this is that data blocks that
were created with SFC are deleted, and the remaining data blocks are assigned initial
values from the load memory.
The RAM area available for logic and data blocks will be modified if you change the
following parameter settings:
– Size of the process image, byte-oriented in the "Cycle/Clock memory" tab
– Communication resources in the "Memory" tab
– Size of the diagnostic buffer in the "Diagnostics/Clock" tab
– Number of local data for all priority classes in the "Memory" tab
interrupts) to the priority classes
5.10 Overview of the parameters for the S7-400H CPUs
Installation of a CPU 41x–H
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