User Manual

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Building Technologies MM8000 OPC Connectivity Configuration Guide
Fire Safety & Security Products 06.2007
4 OPC item classes
This section described an advanced configuration function, which may not needed if
an appropriate data set of OPC item classes is installed in Composer. If in doubt,
check with your technical supervisor.
4.1 Need of conversion rules
OPC items can be based on various data formats. OPC standard includes several
data types, e.g.: integer (I), unsigned integer (UI), real (R), Date, Boolean (BOOL),
String (BSTR). Also, data types may have multiple byte lengths: e.g.: Integer 1 (I1),
Integer 2 (I2), Integer 4 (I4), Integer 8 (I8), in order to allocate data of different size.
Information in the data types may also vary, depending which actual values are
used and associated to a specific application conditions, e.g.: an alarm state.
On the other hand, the MM8000 process image is organised in data points that are
made up of elementary or digital properties (DP). An MM8000 DP represents a
field condition, shown in one of the following states:
– Quiet: indicates the normal condition
– Active: indicates an abnormal or activated condition for 2-state (on/off) proper-
ties (e.g. a communication state that can be normal or faulty)
– Unack: indicates an unacknowledged active condition for acknowledgeable
alarm properties (e.g. a fire alarm or fault that requires acknowledgement from
the operator)
– Ack: indicates an acknowledged active condition for acknowledgeable alarm
properties
– Unreset: indicates a normal condition following an active (or Unack/Ack active)
event for properties that require a reset before entering the Quiet state again
(e.g. a fire alarm requires reset from the operator)
Conversion rules are required to map the OPC data values in to an MM8000 DPs.
In Composer, these rules are called ‘OPC item class’.
4.2 Editing item classes
The item classes available in the Tag properties of OPC items (see Fig 16 above)
are defined in a tool named ‘OPCXMLeditor‘, which can handle various sets of item
classes and save/restore them into/from an XML file.
The OPCXMLeditor tool can be started by the ‘Edit’ button in the ‘Advanced set-
ting’ section of the OPC link / Node tab area (Fig 39).
Fig 39 Starting the editor of OPC item classes