Instructions For Data Logging - Siemens S7-1500 Function Manual

Memory usage and application examples
3.2 Memory usage for data logging
3.2.3

Instructions for data logging

Overview
The following table gives an overview of the instructions for data logging. You will find the
data logging instructions in "STEP 7" in the "Instructions" task card, under "Extended
instructions > Recipe and data logging > Data Logging".
Table 3- 1 Overview of the data logging instructions
Name of the instruction
"DataLogCreate":
Create data log
"DataLogOpen":
Open data log
"DataLogWrite":
Write data log
"DataLogClose":
Close data log
"DataLogNewFile":
Data log in new file
"DataLogClear":
Empty data log
"DataLogDelete":
Delete data log
46
Description
With the "DataLogCreate" instruction you create a data log. The data log is saved on the
SIMATIC memory card in the "\datalogs" directory. You can use the data logging instruc-
tions to save process data. The amount of data in a data log depends on the available
memory space on the SIMATIC memory card.
With the "DataLogOpen" instruction, you open an existing data log on the SIMATIC memory
card. A data log must be open before you can write new data records to it.
The data log opens automatically when the "DataLogCreate" and "DataLogNewFile" instruc-
tions are executed.
A maximum of 10 data logs can be open at any one time. The data log to be opened can be
selected using the ID or name of the data log.
The maximum file size of data logs is 2 GB.
A maximum number of 1000 data log files is possible with firmware version V2.0.
With the "DataLogWrite" instruction you write a data record into an existing data log. Use
the ID parameter to select the data log to which the data record is to be written. To write a
new data record, the data log must be open.
With the "DataLogClose" instruction, you close an open data log. You select the data log
using the ID parameter.
When the CPU changes to STOP state, all open data logs are closed.
With the "DataLogNewFile" instruction you create a new data log. The new data log has the
same properties as an already existing data log. By creating a new data log, you prevent
cyclic overwriting of existing data records.
When the instruction is called it creates a new data log on the SIMATIC memory card using
the name defined in the NAME parameter. You use the ID parameter to specify the ID of the
old data log whose properties you want to apply to the new data log. The ID parameter then
outputs the ID of the new data log.
The "DataLogClear" instruction deletes all data records in an existing data log. The header
of the data log is not deleted (see description of parameter Data structure of the data logs
(Page 45)).
The "DataLogDelete" instruction is used to delete a data log from the SIMATIC memory
card.
Select the data log to be deleted using the NAME and ID parameters.
Structure and Use of the CPU Memory
Function Manual, 10/2018, A5E03461664-AC