User guide

Overview
© Schneider Electric 2011 13
Messaging sequence
The messaging sequences listed below are part of the process for
translating C-Bus messaging to OPC messaging.
 Sequence 1: A building occupant turns Key 1 on which is linked to
DIM1 lighting group.
 Sequence 2: A C-Bus FLR1_DIM1 Group ON message is sent across
the C-Bus network. C-Gate is one of the recipients of the ON message
and stores the DIM1 element to 255. At the physical network level,
this turns the dimmer on to full power.
 Sequence 3: C-Gate notifies the C-Bus OPC Server that groups have
been set to 255. The link between the FLR1_DIM1 lighting group and
the C-Bus OPC Server allows the translation of the lighting level to an
OPC message. The conversion occurs in the following way:
LIGHTING.FLR1_DIM1 = 255
where OPCITEM refers to the OPC refers to the OPC group, LOCAL
indicates the OPC server identifier, LIGHTING represents an OPC
item, and FLR1_DIM1 represents a LIGHTING subitem.
Sequence 4: OPC message is passed to the OPC Client across the OPC
messaging network. The OPC Client control panel indicates that
FLR1_DIM1 group is ON.
Transmitting control data to the C-Bus dimmer
The sequence diagram below illustrates the messaging sequencing
between a C-Bus network, a C-Gate server, a C-Bus OPC Server, and the
OPC Client for sending an lighting control message from the OPC Client.
Figure 8: OPC Lighting OFF message sequence
Messaging sequence
The messaging sequences listed below are part of the process for
translating OPC messaging to C-Bus messaging.
 Sequence 1: The C-Bus OPC Server generates a 0 level for the DIM1
subitem and sends it across the OPC network. The conversion occurs
in the following way:
LIGHTING.FLR1_DIM1 = 0
where OPCITEM refers to the OPC refers to the OPC group, LOCAL
indicates the OPC server identifier, LIGHTING represents an OPC item,
and FLR1_DIM1 represents a LIGHTING subitem.