Siemens SIMATIC PCS 7 Function Manual page 13

PCS 7 OS client
OpenPCS 7 Station
AS
OPC DA (Data Access server)
For read and write access to process values according to the OPC specification OPC DA
V1.00, V2.05a, V3.00.
As an OPC DA server, the OpenPCS 7 station provides other applications with current data
from the OS data management. The OPC DA client can register for current changes or write
values.
OPC HDA (Historical Data Access server)
For read access to archived process values according to the OPC Specification OPC HDA
V1.20.
As an OPC HDA server, the OpenPCS 7 station provides other applications with historical data
from the OS archive system. The OPC client - for example a reporting tool - can specifically
request the data required by specifying the start and end of a period. Various aggregate
functions, such as variance, mean value, or integral, allow preprocessing by the OPC HDA
server and contribute to a reduction in the communication load.
OPC A&E (Alarms & Events server)
For read access to messages, alarms and events according to the OPC Specification OPC
A&E V1.10.
As an OPC A&E server, the OpenPCS 7 station forwards OS messages with all the associated
process values to the subscribers at the production and enterprise management level. OS
OpenPCS 7
Function Manual, 05/2012, A5E02780178-02
OPC client
Office network
OPC DA server
OPC HDA server
OPC A&E server
OPC "H" A&E server
PCS 7 OS server
2.4 Components of OpenPCS 7
Terminal bus
Plant bus
Basics
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