Siemens RDF300 - Page 18

18 / 40
Siemens RDF300…/RDF340.../RDF400… Basic Documentation CE1P3076en
Building Technologies 4BFunctions 28 Aug 2008
The diagram below shows the control sequence of a continuous PI control.
Heating and cooling mode (P01=04)
T[°C] Room temperature
w Room temperature setpoint
Y1 Control command “Valve” Heating
Y2 Control command “Valve” Cooling
XpH Proportional band “Heating”
XpC Proportional band “Cooling”
Y [%]
100
0
w
3076D12
T[°C]
Y2
XpH
Y1
XpC
½ x
dz
½
x
dz
X
dz
Dead zone
Heating mode with manual selection
(P1=2)
Cooling mode with manual selection
(P1=2)
XpH
100
0
w
Y [%]
3076D03
T[°C]
Y1
XpC
Y [%]
100
0
w
3076D14
T[°C]
Y2
This function (4-pipe modulating) is only available with RDF340 (2 analog outputs
DC 0…10 V are required).
Note: The diagrams only show the PI controller’s proportional part.
Control sequence
modulating output