Siemens SIMATIC S7 System Manual

PLC device configuration
6.1 Configuring the operation of the PLC system
S7-200 SMART
142 System Manual, V2.3, 07/2017, A5E03822230-AF
By default, the CPU has no defined retentive memory areas, but you can configure the
retentive ranges:
● The S7-200 SMART CPU models CPU SR20, CPU ST20, CPU SR30, CPU ST30, CPU
SR40, CPU ST40, CPU SR60, and CPU ST60 have a maximum of 10 Kbytes of retentive
memory.
● The S7-200 SMART CPU models CPU CR20s, CPU CR30s, CPU CR40s, and CPU
CR60s have a maximum of 2 Kbytes of retentive memory.
Data retention after CPU power interruption
The CPU performs the following actions regarding retentive memory at power down and
power up:
●
At power down:
The CPU saves the memory ranges designated as retentive to permanent memory.
●
At power up:
The CPU first clears V, M, C, and T memory, copies any initial values from the data block
to V memory, and then copies the saved retentive values from permanent memory to
RAM.
S7-200 SMART CPU memory addresses for retentive ranges
Data type
Desc.
CPU CR20s
CPU CR30s
CPU CR40s
CPU CR60s
CPU SR20
CPU ST20
CPU SR30
CPU ST30
CPU SR40
CPU ST40
CPU SR60
CPU ST60
V
Data Memory
VB0-VB8191
VB0-VB8191
VB0-VB12281
VB0-VB16383
VB0-VB20479
T Timers T0-T31,
T64-T95
T0-T31,
T64-T95
T0-T31,
T64-T95
T0-T31,
T64-T95
T0-T31,
T64-T95
C
Counters
C0-C255
C0-C255
C0-C255
C0-C255
C0-C255
M Flag bits MB0-MB31 MB0-MB31 MB0-MB31 MB0-MB31 MB0-MB31

Siemens SIMATIC S7 Specifications

General

Brand	Siemens
Model	SIMATIC S7
Category	Controller
Language	English