Mixing Valve Controller

FUNCTIONS

The heating mixer block provides mixer control for heating or cooling. It can be used with all common types of mixers (3-way valves and analogue 0-10V mixers etc).

For a three-way valve, the current position of the actuator is stored in the software. Once the position has reached 0% or 100%, a synchronization signal (a continuous on or off pulse which lasts 1.5-times the operation time) is sent to the actuator to ensure that it is in the correct position.

If the mixer hasn’t been in the 0% or 100% position in the last 24 hours, then a synchronization signal (a continuous on pulse lasting 1.5-times the operation time) will be sent to the actuator. The actuator is then immediately brought back to its original position.

A synchronization signal is also sent after each restart of the Miniserver.

BASIC SETUP

The desired target temperature can be set with the analogue input temperature T. The desired temperature can either be set with a virtual input connector or a timer switch.

An actual temperature reading from a temperature sensor in the respective room should be connected to the analogue input AI.
Activating the input stop St locks the outputs in their current states.

Mixing Valve Controller Configuration

OVERVIEW

INPUTS

T Target temperature Connect an analogue value here to set the target temperature, such as a timer/scheduler, a constant or a virtual analogue input.
AI Actual temperature Connect a 1-Wire or analogue temperature sensor here to measure the flow temperature.
St Stop input Will move the valve according to the parameter Sm.
Dis Disable input This input will disable T. The last value for T to be entered is used and any further changes are ignored.

OUTPUTS

AQ Analogue output Connect a 0-10V mixing valve.
Q1 Digital output Connect the open contact for a three-way mixer (hotter).
Q2 Digital output Connect the open contact for a three-way mixer (colder).
Qe Output error This output will be on when the actual temperature AI is either greater or lesser than the target temperature T by 5°C. If the stop input ST is active then Qe will be off.

PARAMETERS

R Sets the mixer running time How long the valve takes to go from open to closed in seconds.
S Adjusts the sampling time How often the heating mixer will adjust the valve in seconds. Default setting is suitable for most heating control systems (typically flow temperature control with a three-way mixer). For more complex control systems such as a heating circuit with an exchanger this parameter may need to be adjusted.
Kp Gain Determines the % gain of the controller. Default setting is suitable for most heating control systems (typically flow temperature control with a three-way mixer). For more complex control systems such as a heating circuit with an exchanger this parameter may need to be adjusted.
Ki Integral component Sets the % integral component of the controller. Default setting is suitable for most heating control systems (typically flow temperature control with a three-way mixer). For more complex control systems such as a heating circuit with an exchanger this parameter may need to be adjusted.
Sm Stop behaviour This parameter controls what happens when the stop input is active:
0 = Unchanged
1 = Open
2 = Close
M Sets the mixing mode 0 = Normal
1 = Inverse (the open output Q1 is considered colder)
Min Minimum output value Sets the minimum output value in percent. So if this value is set to 20 the smallest allowable value of AQ would be 2.
Max Maximum output value Sets the maximum output value in percent. So if this value is set to 50 the smallest allowable value of AQ would be 5.