Auxiliary Functions - Siemens RWD68U Technical Instructions

Technical Instructions
Document Number 155-738
January 14, 2005

Auxiliary Functions

P+I Limiter Function
NOTE: In the following
illustrations, heating
and cooling outputs
are Direct Acting.
Outputs can be
reversed.
Remote Setpoint
NOTE: You cannot select
the remote setpoint
auxiliary function in
Night mode.
Cascade Control
Maximum Priority
NOTE: You cannot select
the maximum priority
auxiliary function in
Night mode.
Page 6
One of the following auxiliary functions can be selected:
• P+I limiter (Absolute, #x2 and Relative, #x3)
• Remote setpoint, #x1
• Cascade control, #x5
• Setpoint compensation, #x4
• Winter/summer operation, Digital #x6, Analog #x7
• Maximum priority, #x8
• Main loop 0 to 10V input, #x9
Day and night operation mode is also available.
Y1 Q1
Y
Q1
Figure 12. P+I Limiter Function.
Q1 Y1
Y
Q1
Figure 13. Remote Setpoint.
Y1
Y
Figure 14. X2 Supply Air Temperature
Sensor.
Q1 Y1
Y
Q1
Figure 15. Maximum Priority,
Cooling.
The limiter function with P+I control
enables absolute (or relative) maximum
or minimum limitation of the supply air
temperature (X2).
X2 X1
When the value drops below or exceeds
Temp. the limiter setpoint, the limiter function
controls and takes priority over the main
setpoint.
A remote setpoint transmitter (QAA25U),
connected to X2 and configured
accordingly, enables setpoint
adjustment.
X2 X1
Active measurement from 0 to 10 Vdc
corresponding adjustable range from
Temp.
–100 to 8000 units.
Passive measurement from 0 to 1000 Ω
corresponding adjustable range from
–100 to 8000 units.
You can select the P+I/P+I room/supply
air temperature cascade control. In this
case, the virtual P+I room temperature
controller determines the setpoint within
the limiter setpoints for the P+I supply air
X2 X1
temperature controller.
Temp.
If the value (0 to 10V) of the input X2 is
greater than the calculated output of the
cooling sequence, the output will use the
X2 input value as output value. This is
active even when the controller is
X1 X2
working with the heating sequence.
Temp.
RWD68U Universal Controller
Siemens Building Technologies, Inc.