Comfort's Built-in Thermostat Function for Heating and Cooling

[ident]

Comfigurator 3.7.6 see http://www.comfortforums.com/forum20/3543.html has a new Functions Category. The Functions are a new concept in Comfort where previously, what required complex programming using Responses can be replaced by the built-in Functions which require the entry of parameters
Functions are implemented in Comfort Firmware 7.039 (yet to be released)
Only Comfort Ultra and Logic Engine shall support Functions

The first functions available are Thermostats and Blinds



The Thermostat function allows Comfort to control the Heating and Cooling valves of a heating system or cooling system or a combined system using Comforts Outputs
Comfort starts with 8 outputs and can be expanded to 96 outputs with Slaves and LEMs and a further 120 outputs using RIOs

In the Thermostat function, Temperatures are kept in Comfort Sensors (1 to 32)
The sensors can be loaded from temperature sensors in SCS, TCS or other systems like KNX or Heatmiser, Zwave which is able to map to Sensors.

The Heating and Cooling Setpoints are kept in Counters. Changing the value in Heating Counter changes the heating  setpoint and changing the value of the Cooling Counter changes the cooling setpoint

A Comfort Flag is assigned to a thermostat. The Thermostat can be turned on or off by setting and clearing the associated Flag

Using Comfort Counters, Sensors and Flags allows the thermostat to be controlled easily by manipulating these in Comfort

The next part will show how to configure the Thermostats Function

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The Thermostat function screen is shown below



8 Thermostats are available
Common Thermostat properties
The common properties for all thermostats are

Maximum Heating Temperature
This is the maximum heating setpoint temperature. If a higher value is put into the Heating Setpoint counter, the setpoint will be limited to this maximum value

Minimum Heating Temperature
This is the minimum heating setpoint temperature. If a lower value is put into the Heating Setpoint counter, the setpoint will be limited to this minimum value

Maximum Cooling Temperature
This is the maximum cooling  setpoint temperature. If a higher value is put into the Cooling  Setpoint counter, the setpoint will be limited to this maximum value

Minimum Cooling Temperature
This is the minimum cooling setpoint temperature. If a lower value is put into the Cooling Setpoint counter, the setpoint will be limited to this minimum value

Hysteresis
This is the Hysteresis temperature value used in the comparison between actual temperature and setpoint.

Each of the 8 Thermostat has the following settings
Sensor Number
This is the Comfort sensor assigned to the Temperature of the Thermostat. 
Sensors assigned to Thermostats must be  unique, i.e. they can be assigned to only 1 Thermostat
The temperature reading can be from TCS01 or external temperature sensor like Heatmiser, Zwave or Velbus

Flag Number
This is the Comfort Flag assigned to the Thermostat.
Assign a flag to a thermostat to enable and disable the thermostat. When the flag is off, the heating and cooling outputs will turn off. When the flag is on, the heating and cooling setpoints will operate the outputs based on comparison between the temperature and the heating/cooling setpoints. Flags assigned to thermostats must be unique, i.e. they can be assigned to only 1 Thermostat.
Note that Flags are not reset by Comfort Reset in firmware  7.039 and above but cold Reset (power off without battery) will reset the Flags to 0

Heating Output Number
This is the Comfort Output number for Heating control. If the Heating Output is Unassigned then  the heating function will not work. Heating and Cooling cannot be on at the same time but they can both be off. Outputs must be uniquely assigned to one heating or cooling only and cannot be also assigned to security outputs, blinds function, Responses or other purposes

Heating Setpoint Counter Number
This is the Comfort Counter number which holds the Heating Setpoint. The counter value is limited by the Minimum Heating Setpoint and Maximum heating Setpoint and cannot be set to any values outside this range.
Setting the heating counter value= 0 will disable the heating function and turn off the heating output
The same counter number can be used in more than 1 thermostat so the same setpoints can be used
Note that Counters are not reset by Comfort Reset in firmware  7.039 and above but cold Reset (power off without battery) will reset the counters to 0

Cooling Output Number
This is the Comfort Output number for Cooling control. If the Cooling Output is Unassigned then  the cooling function will not work. Heating and Cooling cannot be on at the same time but they can both be off. Outputs must be uniquely assigned to one heating or cooling only and cannot be also assigned to security outputs, blinds function, responses or other purposes

Cooling Setpoint Counter Number
This is the Comfort Counter number which holds the Cooling Setpoint. The counter value is limted by the Minimum Heating Setpoint and Maximum heating Setpoint and cannot be set to any values outside this range.
Setting the cooling counter value= 0 will disable the Cooling function and turn off the cooling output.
The same counter number can be used in more than 1 thermostat so the same setpoints can be used
Note that Counters are not reset by Comfort Reset in firmware  7.039 and above but cold Reset (power off without battery) will reset the counters to 0

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Principle of Operation
If the Flag assigned to the thermostat is ON, then the thermostat is enabled. If it is off, then Heating and Cooling outputs will be off and the thermostat  is disabled.
This works by comparing the setpoint with the actual temperature for each Thermostat.
In cooling mode, if the actual temperature is higher than the setpoint + hystereris, the cooling is turned on (and heating off) using an output. If the temperature is lower than setpoint - hysteresis, the cooling is turned off. The hysteresis prevents constant switching between on and off.
In heating mode, the opposite applies. If the temperature is lower than the setpoint, the heating is turned on (and cooling off) until the temp rises to the setpoint. When the temp falls below the setpoint - hysteresis, the heating is turned on again
Heating and cooling cannot be switched on at the same time (interlocking)

The flowchart is shown below. The sequence is triggred by a change in Sensor value (Temperature), a change in the setpoint (counter) value or a change in state of the Flag (on.off).

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Sample Configuration
The cclx file blindshvactest.cclx attached has the configuration descrbed here.
Thermostats 1 and 8 are programmed for this example



The common parameters by default are;
Max Heating Temp = 30
Min Heating Temp = 16
Max Cooling Temp = 26
Min Cooling Temp = 16
Hysteresis  = 1

These can be changed as required

Thermostats 1 and 8 are programmed in the example
Thermostat 1
Sensor =  1
Flag = 1
Heating Output 8
Heating Setpoint Counter  2
Cooling Output 9
Cooling Setpoint Counter 3

Thermostat 8
Sensor =  8
Flag = 8
Heating Output 10
Heating Setpoint Counter  2
Cooling Output 11
Cooling Setpoint Counter 3

Note that you are not allowed to select any Outputs that are used for other purposes like Security Status Outputs, Blinds, and Responses

The Home Control Menu shows how it can be used to set temperature setpoints turn the thermostats on and off and read the temperature of the Thermostats 1 and 8



The \"Execute Response\" link on each control menu action key allows the programmed response to be activated for testing. Execute Responses is also available in the Responses page.
The Feedback is programmed as Sensor 1 so that the temperature can be heard or seen



Next we will show how KT03 can be used to control the thermostats

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This shows how KT03 can be programmed to change setpoints and show temperature


The KT03 Thermostat 1 page is seen below(in KT03 simulation Mode)




Touching the On/Off button will toggle the On/Off state by toggling the assigned flag
The temperature box shows the value of Sensor 1

The Cooling and Heating Setpoints (counter values) are shown. The + and - buttons below the heating and cooling setpoints increment and decrement the heating and cooling setpoint counters.

The Heating and Cooling Boxes show the state of the respective Outputs.
The + and - buttons next to the temperature display is to simulate the temperature to see the effect on the heating and cooling.  Use this to increment and decrement the sensor holding  the temperature and see the heating and cooling outputs turn on and off accordingly. These boxes can be deleted in the final configuration.

The KT03 can fully simulate the action of the thermostat without connecting any hardware

If only heating is required set the cooling setpoint counter value to 0.
If only cooling is required, set the heating setpoint counter value to 0.

[juwi_uk]

Can I ask why for the thermostats are you referencing counter, flags etc by a number dropdown list instead of the names dropdowns you use just about everywhere else in Comfigurator? I\'m sure there must be a reason but I\'d suggest maybe now it is going to be more prone to making mistakes?

Julian

[juwi_uk]

Any why every time I submit a reply does it do it twice!
Julian:?

[ident]

You are right, the counters sensors and flags shoould be selected by name in future

We wanted to get this version out first

[wexfordman]

Looking forward to playing about with this. Just a query though, my heating is controlled by velbus relays, so how do I asking this as a heating output? Do I just have it assigned to any output and associate a velbus response to the output also?

Also, just a point regarding the name rather than counter number, if you are fixing this issue in the next release of configurator could you also apply the same logic to velbus device names? The same issue applies where when holiday responses for velbus modules you reference the module and channel number rather than a device name and it\'s very confusing

[ident]

The function is meant to control heating and cooling is currently by Comfort outputs, not by 3rd party
This would be the simplest and most reliable way to do it instead of having another communication device

There are no  responses triggered by Outputs. Perhaps you could connect outputs to velbus using their input module?


Your point has been noted about velbus names