S7-1500 Memory Concepts

 

Below is the memory area overview: 

Load Memory

Non volatile memory for User program, data blocks, technical object, recipe and data logs.

We can copy additional data to load memory through a web server or explorer.

An inserted Memory card is required for operating the CPU.

For CPU 1518, extra load memory is required for :

1. Linux runtime which runs in parallel with CPU runtime

2. C/C++ runtime application

3. CPU function libraries.

Linux runtime is the environment required for execution of a runtime application and CPU runtime is required

for applications requiring CPU runtime application.

Work Memory

Work memory contains executable code and data blocks. It is integrated in the CPU and cannot be

extended.

For CPU 1528-4PN/DP additional work memory is required for CPU function libraries and C/C++ runtime

applications.

Retentive Memory

It is a non volatile memory for saving limited amount of data in case of power failure. It can be deleted with

memory reset or reset to factory setting.

Additional Memory Area:

It included Process Image Input/Output, Timer, counter, Temporary local data.

Note:

In S7-1500 R/H, both CPU requires memory card of same size. During redundant operations both

CPU executes the user program in parallel. In so doing one CPU takes the role of leading CPU. If one

fails then the second CPU maintains control over the process.

You create the hardware configuration of offline project data once and load it in the primary CPU. the

system synchronizes all data required for redundant operation from primary CPU to backup CPU.

Retentive Memory particular for S7-1500 R/H

After a STOP or POWER OFF of both CPUs, switch the CPU with the more up-to-date data to RUN firstThe more up-to-date data is located in the CPU that controlled the process before STOP or POWER OFF.

This procedure gives you certainty that you are using the more up-to-date retentive data. The precondition for

this is that you did not change any data using STEP 7 or the HMI while the CPUs were in STOP. 

For checking Memory details in TIA: You can find this information for the CPU under "Program info" in

the project tree, "Resources" tab.

Above does not include memory requirements like hardware configuration, recipe, data logs,and HMI

backups. Non simatic files like pdf is also not included.

In S7-1500 We can see memory overview in screen also.

Optimized block access property of global data block helps in data retentivity selective or complete.

For defining memory, timer and counter as retain memory select retain butting in tag table.

Note: This is only for educational purpose. Please cross verify with experts before any implementation.