A Node-RED PID control node and a Hystersis node

PID Control Node

This node has 2 outputs, the first is for heating control, the second is for cooling control.

Both outputs provide a floating point value between 0 and 10.

Settings

The node takes the following configuration values:

• Gain: The % gain to apply to the difference between the setpoint and input value
• Ti: The time in seconds over which to apply the gain value
• Dead Band: The +/- each side of the setpoint to consider the setpoint reached
• Recalculation Time: The time in seconds between each calculation of values
• Setpoint Topic: the topic a message should have to set the setpoint
• Fire Topic: the topic a message should have to enable/disable Fire mode
• Fixed Value Topic: the topic a message should have to enable/disable fixed output mode
• Fixed Value: the value to output when in fixed mode, +ve for heating -ve for cooling

Operations

Before you can use the node you need to set the setpoint, to do this you need send a message with the setpoint value as the payload and a topic set to the Setpoint Topic configured in the editor UI.

Fire mode sets all outputs to 0. Fire mode is enabled by sending a message with a payload of false to and a topic equal to the Fire Topic. To disable Fire mode send a message with a payload of true and a topic equal to the Fire Topic

Hysteresis Node

This node gives a true output value when the input values are outside the deadband of the setpoint and a false when the setpoint is reached.