7.6 Outdoor temperature compensation
With the outdoor temperature compensation function activated, the
product automatically adjusts the mixed flow temperature according
to the outdoor temperature.
Outdoor temperature compensation is set by means of a five-point
temperature curve. The curve allows you to predefine five liquid
temperature setpoints. MIXIT interpolates between the setpoints
and automatically adjusts the liquid temperature accordingly to
compensate for the heat demand.
For heating-coil applications, the curve defines the air temperature.
100
80
60
40
20
-20
-10
10
20
0
0
TM072831
Example of five point temperature curve. Y axis: Setpoint [°C]. X
axis: Outdoor temperature [°C].
7.6.1 Setting outdoor temperature compensation
1.
The control source must be set to bus control by setting BO,0
to 1. See BI, 1 for actual state.
2.
The setpoint source is configured by setting MV,0 to 5. It is also
possible to use an analog sensor connected to the MIXIT unit
by setting MV,0 to 4. The sensor must be configured via
Grundfos GO Remote. See
temperature sensor input and outdoor temperature
compensation
. Outdoor sensor types Pt1000 and 0-10 V are
available.
• If MV,0 is set to 5, the outdoor temperature value is given via
AO,1. Actual value of remote outdoor temperature is
read via AI,1.
3.
Adjust the heat curve offset in AV,4.
• BI,14 indicates if the heat curve offset value is out of range.
4.
Adjust the slope of the heat curve in AV,5.
• BI,13 indicates whether the base curve is linear or non-
linear.
• BI,15 indicates if the heat curve slope factor value is out of
range.
In case the signal from a bus or sensor is lost, the MIXIT unit will
use the fall back temperature setpoint. By default it is 40 °C. It can
be changed via AV,6.
If no outdoor temperature source is connected, the product will give
the warning code 125 in AI,0, except if the temperature source is
configured for a 0-10 V analog sensor.
ID
Object name R/W
Description
BO,0
Set Control
Source
W
0: Local control (default)
1: Bus control
BI,1
Status Fan
And Dampers
ED
R
0: Disabled
1: Enabled
This status indicates that the system
is in temperature control state.
MV,0
Config Temp
Setpoint
Source
[Enum]
R/W
This selects the source of the
temperature setpoint.
1: default_setpoint
2: ana_temp_setpoint
3: temp_setpoint_remote
4: outdoor_temp
5: outdoor_temp_remote
6 and above: reserved
•
4: Associated with an analog
sensor connected to the
product and objects:
- AV,4 (Config Heat curve
offset (+/-) [°C])
- AV,5 (Config Heat curve
slope (+/-) [-]).
•
5: Associated with objects:
- AO,1 (Set Outdoor
Temperature Remote [°C])
- AI,1 (Data Outdoor Temp
Remote [°C])
- AV,4 (Config Heat curve
offset (+/-) [°C])
- AV,5 (Config Heat curve
slope (+/-) [-])
For all options the actual
temperature setpoint used by the
algorithm can be read at AI,2 (Data
Act Temp Setpoint [°C]).
AO,1
Set Outdoor
Temperature
Remote [°C]
W
Outdoor temperature value via
fieldbus. It is enabled via MV,0 = 5
and by setting the control source to
bus control via BO,0.
AI,1
Data Outdoor
Temp
Remote [°C]
R
Actual value of remote outdoor
temperature.
AI,2
Data Act
Temp
Setpoint [°C]
R
Actual temperature setpoint used in
temperature controller.
If the limiter function is set to off, it is
the same as the actual reference
temperature derived from the set
reference temperature mode via
MV,0.
AV,4
Config Heat
curve offset
(+/-) [°C]
R/W
Adjusts the heat curve offset in
degrees Celsius. It is used when
MV,0 = 4 or MV,0 = 5.
AV,5
Config Heat
curve slope
(+/-) [-]
R/W
Adjusts the slope of the configured
heat curve.
1 equals the configured heat curve
and 1.5 equals the configured slope
multiplied by 1.5.
17
English (GB)
