@mschaeffler/node-red-thermostat NPM

@mschaeffler/node-red-thermostat

A Node Red node to control an (electric) heater.

image of example flow

Install

$ npm install @mschaeffler/node-red-thermostat

Closed Loop Control

A heating device that just can be switched on and off, can be closed loop controlled:

closed loop control

The on / off cycles are done like this:

cycle state

The on time is calculated in this way:

formula

with this values |value |description | |:------|:---------------| |t_on |time of on cycle| |T_nom |nominal Temperature, parameter nominal| |T_act |actual temperature, msg.payload.temperature| |s |minimal Delta, parameter summand| |f_cycle|$1.4$ for the 1st cycle, $1.2$ for the 2nd, then $1$| |f_msg |control coefficient, msg.payload.factor| |f_node |control coefficient, parameter factor| |t_cycle|time of complete cycle, parameter cycleTime|

Input

msg.	type	description
payload	object	data to control the thermostat

There are two different ways to control the thermostat:

direct control

msg.payload is a destinct value:

msg.payload	type	description
`true`	boolean	starts heating according to already set data
`false`	boolean	stops heating
`on`	string	starts heating according to already set data
`off`	string	stops heating
`1`	number	sets the cycle count to 1 and starts heating
`2`	number	sets the cycle count to 2 and starts heating
`3`	number	sets the cycle count to 3 and starts heating
`4`	number	sets the cycle count to 4 and starts heating
`5`	number	sets the cycle count to 5 and starts heating
`0`	number	stops heating

control with objects

msg.payload is an object with at least one of these members:

msg.payload.	type	description
temperature	number	actual temperature for the closed loop control
block	boolean	blocks the heating (e.G. open window)
nominal	number	nominal temperature
factor	number	multilies the control coefficent (parameter factor) with this value
cycleTime	number	sets the cyclic time
cycleCount	number	sets the nuber of cycles

Outputs

state feedback

This is the general feedback: heating is on or off.

msg.	type	description
topic	string	parameter `topic`
payload		value according to parameter `feedback`

control output

This controls the heater according to the cycles.

msg.	type	description
topic	string	parameter `topic`
payload	boolean	control value to switch the heater

Parameters

config	type	description
topic	string	topic value for the output messages
nominal	number	nominal temperature for the closed loop control
minDelta	number	actual temp must be by this value lower then the nominal to start heating
summand	number	additional summand for the closed loop control
factor	number	control coefficient for the closed loop control
cycleTime	number	time period of one heating cycle
cycleCount	number	number of heating cycles
feedback	string	style of the state feedback