ABB i-bus® KNX
PLANNING AND APPLICATION
12
Planning and application
12.1
Priorities
12.1.1
Priorities for controller mode
Valve
a) Bus voltage failure
b) Operating mode overridden
c) Safety mode →
d) Forced operation
e) i-bus® Tool
f) Operating mode
Manual operation (only VC/S 4.2.1)
g) Manual valve override
h) Controller mode via group object
Operating mode normal (master)
)
i) Bus voltage recovery
12.1.2
Priorities for actuator mode
Valve
a) Bus voltage failure
b) Forced operation
c) i-bus® Tool
d) Operating mode
Manual operation (only VC/S 4.2.1)
e) Manual valve override
f) Actuator mode via group objects
g) Bus voltage recovery
12.2
Basic knowledge
12.2.1
2-pipe and 4-pipe systems
2-pipe system
In a 2-pipe system, one pipe is used to supply the heating/cooling devices with warm or cold water. Only
one operating mode (
Heating
/
Cooling
) can be active in the complete system. Switching between
Heating
and
Cooling
is performed centrally in this system. The device receives information about the
current operating mode via the bus (ABB i-bus® KNX).
4-pipe system
In a 4-pipe system, two separate pipes are used to supply the heating/cooling devices with warm or cold
water. The separate pipes permit switching between heating mode and cooling mode. Switching be-
tween
Heating
and
Cooling
is performed centrally via the bus (ABB i-bus® KNX) or is controlled by the
controller.
Product manual | EN-US | VC/S 4.x.1 | 2CDC508220D0211 Rev. B
173
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