Proportional Integral (PI) Loop Control

3 Minute Read

| How it Works

The PI Loop Control terminal profile can be used for a wide range of applications. Using an input to reset or modulate an output. Some examples below cover the basics of the Proportional side of the PI Loop Controller. The integral means if time keeps going by and the input is not receding to its Target then the output will slowly modulate more to bring the input signal down.  

The examples below cover the Proportional aspect of the PI Loop only to conceptualize what will occur. The integral portion will turn up the output if the input does not respond to the output for some time. 

Single Target

Modulating Target

Zero Error at Midpoint

| Wiring

Analog Input 

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Thermistor/ Temperature Input 

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| Configuration

The Proportional/ Integral controller is highly configurable and can be used in numerous applications for modulating an output or providing setpoint resets. As soon as you pair your SmartNode as a PI controller you will be faced with some options to correctly configure the physical characteristics of your application. 

Analog-in1 Input Sensor - Select the option for what type of Analog sensor you are using, choose a generic 0-10Vdc if your sensor option does not exist, or choose Not Used if you plan to use a temperature sensor. 

TH-in1 Input Sensor -Thermistor input sensor option. If you are using a 10K Type II thermistor to read temperature and modulate and output, choose the option. 

Use Analog-in2 for dynamic Setpoint -If your setpoint is not meant to be static and can change based on the output of another device. You can enable this so that your Target value is no longer used and the value coming in Analog 2 will be used as the Target value. 

Analog-in2 Input Sensor - Select the type of sensor option that will be used for setting your dynamic Target value. If your specific device type does not exist you can always use the Generic 0-10Vdc option. 

Target Value -Your target value is your set point. Set this value to the desired target value. (e.g) pressure target value maybe 0.5"w.c.)

Expected Error Range -The expected error range  + your Target Value that you will reach maximum output. 

Analog-out1 at Min Output -The minimum output on AO1. If you are at or below the setpoint than your output will be at this value. 

Analog-out1 at Max Output -The maximum output on AO1 if you are at or above Target Value + Expected Error Range. If you are above your maximum expected error range then your AO1 will go to this value. 

Expected Zero Error at Midpoint -Instead of using only additive logic you can go +/- for your Expected Error range. (E.g. Your target value is 5Vdc and your expected error range is 2Vdc. with this option disabled at 7Vdc, you will be at your max output, and at 4Vdc you will be at your minimum output. With this option enabled now at 7Vdc you will be at Max output and 4Vdc your output will be 2.5Vdc.) 

| Failsafe Mode

When the SmartNode/HelioNode loses the connection with the CCU, the system enters the failsafe mode where the required controls are still available from the SmartNode/HelioNode itself.

| Feature Availability Version