RWD68U Universal Controller
Technical Instructions
Document Number 155-738
January 14, 2005
Dependent Control Loops
TH0751R1
Y1
Max V
Heating
Temp.
Setpoint
O
u
tput
V
o
lt
age
Q1
OFF
ON
Min V
Figure 6. Two Direct Acting
Sequences
(Application No.: 20 to 29).
TH0750R1
Y1
Max V
Cooling
Temp.
Setpoint
O
u
tput
V
o
lt
age
Q1
OFF
ON
Min V
Figure 7. Two Reverse Acting
Sequences
(Application 60 to 69).
Independent Control Loops
TH0752R1
Y1
Min V
Temp.
Setpoint
XP
Heating
Heating
O
uptut
V
o
lt
agee
OFF
ON
Q1
SD
SD
SD
2
2
Max V
Figure 8. One Reverse Acting, One
Direct Acting Sequence
(Application 30 to 39).
TH0753R1
Y1
Min V
Temp.
Setpoint
Cooling
Cooling
O
uptut
V
o
lt
age
OFF
ON
Q1
SD
SD
SD
2
2
Max V
Figure 9. Two Direct Acting
Sequences
(Application 70 to 79).
Universal Input X1
The primary input for a Siemens Ni 1000 temperature sensor, a Pt 1000 temperature
sensor, or a 0 to 10 Vdc active input.
Universal Input X2
The secondary input for a Siemens Ni 1000 temperature sensor, a Pt 1000
temperature sensor, an active/passive remote setpoint transmitter, or a 0 to 10 Vdc
active input.
Digital Input D1
Selects the day/night changeover. Changeover occurs via potential-free contacts
between D1 and M. Typically, a time clock controls D1 input.
Analog Output Y1
Output Y1 can be configured for either reverse or direct acting. The modulating
voltage output (Y1) controls the devices requiring a 0 to 10 Vdc signal.
Digital Output Q1
Output Q1 can be configured for either reverse or direct acting control.
Example
TH0754R1
X1
Y1
Q1
Temp.
Y
Q1
X1 Room
temperature
Q1
Heating, reverse action
Y1
Cooling, reverse action
Figure 10. Constant Volume with Temperature Control,
Reverse Acting/Reverse Acting.
TH0754R1
X1
Y1
Q1
Temp.
Y
Q1
X1 Room
temperature
Q1
Heating, direct action
Y1
Cooling, direct action
Figure 11. Constant Volume with Temperature Control, Direct Acting/Direct Acting.
Siemens Building Technologies, Inc.
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