Danfoss DHP-R 7Ua, User Manual

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VUBMG102
76*'+
Danfoss – 37
5 external and superior control systems
5�1 OPC-server for connection to sCaDa-systems
When managing larger groups of buildings it is not uncommon that a superior
building management system is used to supervise all control equipment in the
buildings. This is can be a so called SCADA system. OPC is an open standard for
transferring information from, for example, PLC-systems to SCADA systems or
other applications.
For the WM HPC there is an OPC server software available. This can be run on
a central server at the building manager. The server software gathers informa-
tion from WM HPCs in the buildings through TCP/IP and makes it possible for
the SCADA system to get this information through OPC.
5�2 alarm management and e-mails
The most important information from a controll system in a building is most
likely the alarms that tells if something is wrong. With the web licence comes
the possibility to send alarm using e-mail. These e-mails are designed to be
readable both by humans an machines. As alarms by e-mail becomes more
and more common alarm distribution systems that can receive alarms by e-
mail and re-distribute to relevant personnel also becomes more common. E-
mail thus becomes another way to connect WM HPC to superior supervisory
systems.
5�3 Control by external PlC
In some cases there may be a need to control the heat pump from another
control system than the one in the WM HPC. The alarms and protective func-
tions built in to the heat pump should still be active, and there is therefore a
special mode in the WM HPC for external control.
If a heart pump is set to slave mode without being connected to a master heat
pump it will signal an alarm that communication with master has failed. By
grounding the temperature inputs for outdoor temperature and hot water
start temperature the WM HPC will enter external controller mode. The com-
munication alarm will be silent and the pump can be started by grounding the
primary supply temperature sensor input. The heat pump will stop when the
sensor input is open, which means that the heat pump can be controlled using
a simple relay.
The slave pump settings in the WM HPC are still valid, except for the setting
regarding hot water. The hot water switchover valve must be controlled by the
external control system. The WM HPC still manages the protective alarms ant
timeouts, and will ensure that the heat pump will not start again until it has
been standing still for at least five minutes after a stop.