Siemens SIMATIC S7-300 CPU Data: CPU 315-T-2 DP User Manual

Memory concept
6.4 Measured value log files
Measured value logging:
• Before the data volume can exceed work memory capacity, you should call
SFC 84 "WRIT_DBL" in the user program to swap measured values from the DB to load
memory.
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Figure 6-5 Handling measured value log files
• You can call SFC 82 "CREA_DBL" in the user program to generate new (additional) static
DBs in load memory which do not require RAM space.
The data written to load memory are portable and retentive on CPU memory reset.
Note
SFC 82 is terminated and an error message is generated if a DB already exists under the
same number in load memory and/or RAM.
Evaluation of measured values:
• Measured value DBs saved to load memory can be uploaded and evaluated by other
communication partners (PG, PC, for example).
Note
The active system functions SFC 82 to 84 (current access to the MMC) have a distinct
influence on PG functions (block status, variable status, load block, upload, open, for
example).
This typically reduces performance (compared to passive system functions) by the factor
10.
With the
Technology CPU, you can also generate non-retentive DBs using SFC 82
(parameter ATTRIB -> NON_RETAIN bit.)
in order to prevent data losses, do not exceed this maximum of delete/write operations. Also
refer to the SIMATIC Micro Memory Card (MMC) section in the "Structure and
Communication Functions of a CPU 31xC" chapter.
S7-300 CPU Data: CPU 315T-2 DP
6-16 Manual, 12/2005, A5E00427933-02

Siemens SIMATIC S7-300 CPU Data: CPU 315-T-2 DP Specifications

General

Programming Language	STEP 7
Power Supply	24 V DC
Number of DP masters	1
Processable Technology objects	Yes
Number of counters	256
Number of timers	256
S7 communication	Yes
Number of connections for S7 communication, max.	16
PG/OP communication	Yes
Global data communication	Yes
Integrated DP interface	Yes
Integrated PROFINET interface	No
SIMATIC Computing Platform	No
Operating Temperature	0 to 60 °C
Integrated Interfaces	MPI, DP
Communication	PROFIBUS DP
Cycle Time	0.1 ms
Engineering with	STEP 7
Backup available	Yes
Transmission rate, max.	12 Mbit/s

Summary

Product Overview

Integrated technology of Technology CPU

Details the integration of technology and motion control functions within the SIMATIC CPU.

Setting up an S7-300 with a Technology CPU

Configuring

Covers configuration aspects like single-tier setup and subnets.

Addressing

Status and error displays of the Technology CPU

Explains the meaning of CPU LEDs for status and error indication.

Communication with the S7-300

MPI/DP interface (X1)

DP(DRIVE) interface (X3)

Communication services on the MPI/DP interface (X1)

Provides an overview of communication services like PG, OP, S7, and Global data communication.

Routing

Memory concept

Memory areas and retentive address areas

Memory functions

Covers functions for generating, modifying, or deleting programs and blocks.

CPU memory reset and restart

Cycle and response times

Cycle time

Explains the definition, calculation, and influencing factors of CPU cycle time.

Response time

Defines response time and analyzes factors affecting its variation and calculation.

Interrupt response time

Technical data

CPU 315T-2 DP

Lists detailed technical specifications for the CPU, including versions, technology objects, memory, and execution times.

Integrated Inputs/Outputs for Technology

Describes the arrangement and technical specifications of the CPU's integrated digital inputs and outputs.

Information for the Changeover to the Technology CPU

Changed behavior of certain SFCs