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18 - External units
18�8�2 Combining units
The WMPro and GFBI are both able to switch easily between
dierent protocols and speeds. But certain units may be
confused by communication they do not understand. Most
protocols include protective mechanisms making it highly
unlikely that they will misinterpret or become confused by
extraneous trac, but a lot depends on the particular imple-
mentation in dierent units. Each case should be considered
individually.
The update time is another important factor in systems using
external units. Some types of unit need to exchange informa-
tion frequently, for example expansion units with inputs and outputs used in
a control system. There is nothing to stop you including several units in the
same system if all the units use high communication speeds, short messages
and short response times. But it is not a good idea to combine these units
with a large number of M-Bus units running at 300 baud.
If a unit fails to respond, the WMPro waits for the timeout period specied in
the type denition. One or more faulty units can therefore have a signicant
eect on the update times.
The operator panel works best if it is connected to the expansion port. You
could also connect it to the same terminals as GFBI, but it does not always
work well with other units. The operator panel needs fast communication.
That is why every second message is sent to the operator panel if necessary.
Even so, the speeds might be much slower if the operator panel is used in
combination with other units.
18�9 WMShare
18�9�1 WMShare export
The Settings/Advanced/External units
page contains two WMShare tabs. In
WMShare export, you can specify the
channel values you want to export,
making them available to other de-
vices.
A key is a name or identier for the
value being exported. This is the
name that is used by the devices
importing the value.
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