merten MEG6212-03 Series, Руководство по эксплуатации, Страница: 42 / 49

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© 2009 Merten by Schneider Electric
Push-button, 4-gang plus with room temperature control unit and IR receiver
Multifunction with RTCU and FanCoil 1817/1.0
Getting to know and parameterising the room temperature control unit
Setting rules for the PI control
In general:
• Large system increases (e.g. high heating output,
steep characteristic curves for valves) are controlled
with large proportional ranges.
• Slow heating systems (e.g. underfloor heating) are
controlled with high-level reset times.
If no satisfactory control result is achieved by selecting
an appropriate heating or cooling system, you can im-
prove the adaptation "via control parameters":
• Small proportional range:
Large overshoot for setpoint changes (also continu-
ous oscillation under certain circumstances), rapid
adjustment to the setpoint.
• Large proportional range:
No (or little) overshooting, but slow adjustment.
• Short reset time:
Rapid correction of control deviations (ambient condi-
tions), risk of continuous oscillation.
• Long reset time:
Slow correction of control deviations.
The framework conditions for setting the cycle time are
as follows:
• For small values, the switching frequency and the bus
load are increased.
• For large values, temperature fluctuations are created
in the room.
• A short cycle time for rapid heating systems (e.g. elec-
tric heating).
• A long cycle time for slow heating systems (e.g. un-
derfloor warm water heating).
Examples
Warm water radiator heating with motorised valve
drives:
Cooling ceiling with motorised valve drives:
Switching electric radiator heating:
Air conditioning with 4-duct (2-circuit) air convector sys-
tem (e.g. switching valve drives):
Temperature limitation using shading facility:
t 1 t 2
Room temperature
Set
point 2
Set
point 1
Time
Characteristics Parameter Setting
Heating only Controller type Heating
Correcting variable out-
put
Continuous PI control
Adjust the controller to
the heating system
Warm water heating
(5 K/150 min)
Characteristics Parameter Setting
Cooling only Controller type Cooling
Correcting variable out-
put
Continuous PI control
Adjust the controller to
the cooling system
Adjustment via control
parameter
Cooling proportional
range
Approx. 5 K (depending
on the application)
Reset time for cooling Approx. 240 min. (de-
pending on the applica-
tion)
Characteristics Parameter Setting
Heating only Controller type Heating
Correcting variable out-
put
Switching PI control
Adjust the controller to
the heating system
Electric heating
(4 K/100 min)
Characteristics Parameter Setting
Heating or cool-
ing as required,
with automatic
switching
Controller type Heating and cooling
Correcting variable out-
put - heating
e.g. switching PI control
Adjust the controller to
the heating system
Air convector
(4 K/90 min)
Correcting variable out-
put - cooling
e.g. switching PI control
Adjust the controller to
the cooling system
Air convector
(4 K/90 min)
e.g. automatical-
ly switch be-
tween heating
and cooling
Switch between heating
and cooling
automatically via the
controller
Characteristics Parameter Setting
Cooling only Controller type Cooling
Correcting variable out-
put - heating
Switching 2-step control
Hysteresis Large (e.g. 2 K)