I’m using latest version of Openhab2 on a Raspberry Pi3 (latest OS). I’m having a simple heating solution:
Danboss thermostat on the wall and Fibaro smart plug between electric heater and a wall plug. The logic is that when thermostat sees the room is cold, it turns on the smartplug, which turns on the heater and if thermostat sees the room is in set temperature, it turns off the plug again.
I’m not experienced coder so I found a suitable rule somewhere from this forum, which works for me but there’s something that annoys me and I need help solving it. The rule itself is as follows:
ElutoaSetpoint = Thermostat Setpoint
ElutoaTemp = Current room temperature
ElutoaRadikas = Fibaro smart plug
rule "Elutoa temperatuur"
when
Item ElutoaSetpoint changed or
Item ElutoaTemp changed
then
var Number cur_temp = ElutoaTemp.state
var Number setpoint = ElutoaSetpoint.state
val hysteresis = 0.5
if ((cur_temp).floatValue < ((setpoint).floatValue - hysteresis)) {
if (ElutoaRadikas == OFF) {
sendCommand(ElutoaRadikas, ON)
}
}
else {
sendCommand(ElutoaRadikas, OFF)
}
end
The system sees the temperature with two decimal places (example 22,25). So every time the temperature changes 0,01 degrees, the thermostat sends the “OFF” command.
2018-08-30 14:48:32.877 [vent.ItemStateChangedEvent] - ElutoaTemp changed from 24.27 to 24.23
2018-08-30 14:48:32.909 [me.event.ThingUpdatedEvent] - Thing 'zwave:device:6675270d:node3' has been updated.
2018-08-30 14:48:33.343 [ome.event.ItemCommandEvent] - Item 'ElutoaRadikas' received command OFF
2018-08-30 14:53:33.876 [vent.ItemStateChangedEvent] - ElutoaTemp changed from 24.23 to 24.19
2018-08-30 14:53:33.899 [ome.event.ItemCommandEvent] - Item 'ElutoaRadikas' received command OFF
2018-08-30 14:53:33.934 [me.event.ThingUpdatedEvent] - Thing 'zwave:device:6675270d:node3' has been updated.
2018-08-30 14:58:34.865 [vent.ItemStateChangedEvent] - ElutoaTemp changed from 24.19 to 24.13
2018-08-30 14:58:34.904 [me.event.ThingUpdatedEvent] - Thing 'zwave:device:6675270d:node3' has been updated.
2018-08-30 14:58:34.920 [ome.event.ItemCommandEvent] - Item 'ElutoaRadikas' received command OFF
How can I modify the code so that the “OFF” command is sent only when the change is 0,5 degrees (hysteresis)?
@hr3 code is more elegant than two rules. You may want to add + hysteresis to the else if. That way you have a larger hysteresis to prevent short cycling.
Hi,
Moving the var’s to the top (right before “when”) for some reason gave me some kind of error so I moved them back.
But I used your suggestion to use two rules, without the “else” and it works. I’ll test some time, when the weather gets colder and see how it performs and if the cycles get too short then I’ll have a look of the @hr3 suggestion.
Change the hysteresis to a Number val
As your variable and hysteresis are now all numbers you won’t need the floatValue anymore
rule "Elutoa temperatuur"
when
Item ElutoaSetpoint changed or
Item ElutoaTemp changed
then
var Number cur_temp = ElutoaTemp.state as Number
var Number setpoint = ElutoaSetpoint.state as Number
val Number hysteresis = 0.5
if (cur_temp < (setpoint - hysteresis)) {
if (ElutoaRadikas.state != ON) {ElutoaRadikas.sendCommand(ON)}
}
else if(cur_temp > setpoint + hysteresis) {
if (ElutoaRadikas.state != OFF) {ElutoaRadikas.sendCommand(OFF)}
}
end
Would there be a way to implement a switch to decide wether this rule activated or not? I’m planning to run my boiler using a general wireless thermostat to control schedules and so forth and then have valves on every radiator and sensors to determine a certain room temperature. With the rule set out as it is if the boiler was off and the room Setpoint was say 21 but the actual room temperature was 17 the valve would be open using electric and opening the valve unnecessarily. I would read the boiler state and then use a switch item to control wether the rule would run or not. Or would it just be a case of adding a when Boiler_State is on carry on rule if off wait till Boiler_State changed to on? Can anybody help?
ive got a sensor connected to my boiler. Boiler_Status
this is the rule i came up with but its coming up with errors.
rule “Kids Bedroom heating”
when
Item Boiler_Status changed to ON then
Item Kids_Bedroom_Temp_Setpoint changed or
Item Bed_Temperature changed
then
var Number cur_temp = Bed_Temperature.state as Number
var Number setpoint = Kids_Bedroom_Temp_Setpoint.state as Number
val Number hysteresis = 0.5
if (cur_temp < (setpoint - hysteresis)) {
if (Bed_Heater.state != ON) {Bed_Heater.sendCommand(ON)}
}
else if(cur_temp > setpoint + hysteresis) {
if (Bed_Heater.state != OFF) {Bed_Heater.sendCommand(OFF)}
}
end
Some items are just demo items at the minute
this is the error i get
2020-05-10 16:16:16.755 [WARN ] [el.core.internal.ModelRepositoryImpl] - Configuration model ‘heating.rules’ has errors, therefore ignoring it: [4,5]: mismatched input ‘Item’ expecting ‘end’
Move Boiler_Status to the then section and check the condition.
rule "Elutoa temperatuur"
when
Item ElutoaSetpoint changed or
Item ElutoaTemp changed
then
var Number cur_temp = ElutoaTemp.state as Number
var Number setpoint = ElutoaSetpoint.state as Number
val Number hysteresis = 0.5
if (cur_temp < (setpoint - hysteresis) && Boiler_Status.state == ON) {
if (ElutoaRadikas.state != ON) {ElutoaRadikas.sendCommand(ON)}
}
else if(cur_temp > setpoint + hysteresis) {
if (ElutoaRadikas.state != OFF) {ElutoaRadikas.sendCommand(OFF)}
}
end
Or just check if the switch is off and do nothing with:
if (Boiler_Status.state == OFF) return;
Put this at the first part of the then part of rule. If the switch is off the rule will do nothing.
i have just run the rule and it works perfectly apart from the Bed_Heater is still on when the boiler status changes to off because the setpoint temp is not met, could i implement a or Bed_Heater.state OFF, on the else if line?
You may want to add + hysteresis to the else if. That way you have a larger hysteresis to prevent short cycling.