Specifications

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The SCADA I/O tag database is created in Vijeo Citect from the UNITY variable database.
We recommend creating at an early stage the most complete I/O tag database in Vijeo Citect, by importing the
relevant PLC tags. The goal is to have a unique tag conguration from PLC to SCADA.
Database creation b
The SCADA database is created from the UNITY PLC variable database. It is advisable to create a lter in UNITY
to select only the required SCADA variables.
The ltered UNITY le is then exported to an XVM le used by Vijeo Citect.
Procedure:
In the Unity application, to create the lter (see below), use the “custom” eld of variables that should be
exchanged with SCADA :
- VJA for alarms v
- VJT for trends v
- VJC for other variables v
Remark:
To avoid variables list overload, into Citect Explorer\ Tool \ Import Tags, check off “ Purge deleted tag not found
in data source.
OFS server and XVM le are used for the variables exchange, the procedure in OFS is::
declare the device -
the address of the PLC -
the name and lepath of the associated XVM le -
Database consistency b
During application debug, discrepancies between PLC and SCADA databases can appear. We recommend using
one of the following two methods:
Case 1, OFS has dynamic access to the XVM le. In this case we have to check in UNITY application the option v
“Auto saving on download = XVM le”.
After each PLC application modication, the XVM le is updated and downloaded therefore database consis-
tency between PLC and SCADA is guaranteed.
Case 2, OFS has no dynamic access to the XVM le. In the “Device Overview” folder of OFS conguration tool, v
“Consistency level” parameter must be set to “Debug” mode. In this case, OFS accepts discrepancies between
PLC and SCADA.
4-Conguration
SCADA system conguration
SCADA system
principle