LOYTEC L-Proxy, Руководство пользователя, Страница: 131 / 150

L-Proxy User Manual 131 LOYTEC
Version 3.1 LOYTEC electronics GmbH
OPC server cannot poll but must receive updates. The input NVs on the L-Proxy can then
be configured to actively poll the source node at a defined poll cycle and the updates are
sent to the destination node.
node2
lproxy1 2
nviFilePos
nviFileReq
nviRequest nvoAlarm
nvoAlarm_2
nvoFileStat
nvoStatus
nvoSupplyVolt
nvoSystemTemp
Node2
nviSystemTemp nvoSystemTemp
Gateway Proxy 2
node1
nvi01temp
Ctrl
Figure 139: Active poll of nvoSystemTemp on node2 from nviSystemTemp on node lproxy1 2.
In our example the output network variable nvoSystemTemp on node ‘node2’ in Figure
139 cannot send updates by itself but must be polled. In our case the lproxy1 2 polls this
output network variable with the input nviSystemTemp using a poll cycle of 30s as defined
in the data point manager dialog (see Figure 140).
Figure 140: Poll cycle setting for input nviSystemTemp on node lproxy1 2
In this example lproxy1 2 sends an update out on nvoSystemTemp when the polled value
changes. If the 30s are too long in some circumstances, a forward poll can be configured.
Forward poll means that if poll requests are received from the destination node (node1) on
the output side of L-Proxy, they are forwarded to the source node (node2) in addition to the
periodic polls generated by the L-Proxy. To configure a forward poll set the Max Cache
Age property to ‘0’ as shown in Figure 141.