Siemens RDG20 KN Series - Page 89

Functions
Control sequences
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The diagrams below show the control sequence for modulating PI control.
Heating and cooling mode (P001 = 4)
Heating mode with manual selection
(P001 = 3) or
to save energy (P010 = 2 & P014) in the
heating sequence
Cooling mode with manual selection
(P001 = 3) or
to save energy (P010 = 2 & P015) in the
cooling sequence
T[°C] Room temperature
YH1, YC1 Control command "Valve"
stage 1
w Room temperature setpoint
YH2, YC2 Control command
"Valve" stage 2
X
dz
Dead zone (P055)
XpH Proportional band "Heating"
(P050)
w
D
Setpoint differential (P056)
XpC Proportional band "Cooling"
(P052)
The diagrams only show the PI thermostat’s proportional part.
For setting sequence and control outputs, see Application overview [➙ 43],
Sequence overview (setting via P001) [➙ 77] and Control outputs [➙ 101].
● For applications with different signals, On/Off (1
st
stage) and DC (2
nd
stage),
heating/cooling P-band modulating (P050, P052), a small switching differential
SDH / SDC (P051, P053) is suggested to start 1
st
sequence as soon as heating
/ cooling demand is requested.
● Set the heating/cooling flow limitation function with parameter
P256(RDG264KN only), P260 & P261 (RDG26..) in this application. See
Additional functions [➙ 48].
Modulating control:
PWM or DC 0…10 V
Note
Note