Archiving; Introduction - Siemens SIMATIC PCS 7 Configuration Manual

10.4

Archiving

10.4.1

Introduction

Backing up process values and messages
In a PCS 7 plant, you can archive various types of data which are produced in process mode.
This data includes process values (analog and binary) and messages.
PCS 7 provides the option of automatically creating archive tags for process values that are
marked accordingly. In order for this to happen, the process values must be labeled as relevant
for archiving in the SIMATIC Manager using the "Archive" attribute. This attribute can only be
set for block I/Os intended for operator control and monitoring. The available labels, "Archiving"
and "Long-term archiving", specify whether the process value should also be saved for the
long term if a Process Historian is used. If you have selected the "Create archives" option,
PCS 7 then creates the labeled archive tags automatically when the "Compile OS" function is
executed.
The recording and archiving times can be adapted to the physical type of the process tag
immediately after this step in a clear display (in the SIMATIC Manager process object view,
for example).
The individual process tags can be roughly divided into four classes for display purposes:
● Temperature measurement (CT) 10 s to 20 s
● Level measurement (CL) 5 s to 10 s
● Pressure measurement (CP) 3 s to 5 s
● Flow measurement (CF) 0.5 s to 3 s
Depending on how the components have been dimensioned, their values may differ from the
example values given here.
By default, archiving is performed locally on the OS servers. The PCS 7 system distinguishes
between archive tags which must be archived in intervals of under one minute (TagLogging
Fast) and those which must be archived in intervals of over one minute (TagLogging Slow),
where one minute is the default setting. The system assigns the tags to two separate archive
databases accordingly in online mode. If these archive values are mixed together in the
configurable "process value archives" or the system archive, this will not have any effect on
the process of assigning them to different databases.
The following figure shows the structure of the archives, which are designed as circular logs
and use single segments.
Compendium Part A - Configuration Guidelines (V8.2)
Configuration Manual, 08/2016, A5E38166869-AA
Configuring OS functions
10.4 Archiving
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