controlsfreak.dev /// FIELD REFERENCE OK
BMS Field Reference

Tools for those in controls,
built for the field.

A reference site for building-controls people. Open calculators and lookups for the math you don't want to redo at the panel — BACnet/IP, Modbus registers, signal scaling, psychrometrics, thermistors. Alongside, a growing set of explainers that walk through hydronic loops, load piping, VFDs, and pump control end-to-end. No login, no ads, no tracking — view-source still works, and the same pages run ten years from now.

AI / AO Scaling Modbus Register Viewer PID Tuning BACnet/IP Hex Psychrometric Chart Thermistor / RTD Lookup More coming
OK VERSION v2.1.0 LAST BUILT UPTIME 24×7

Start Here

Tools
Calculators & lookups →
Calculators and lookups for the parts of the job that come up over and over — psychrometric staging, signal scaling, register and address conversions, thermistor curves, a practice VFD keypad. Open one, get an answer, get back to work.
 Education
Learn the fundamentals →
A connected set of explainers, not a glossary. The current arc: PID control → hydronic loops → load piping → VFDs → pump control, each page asking one question and answering it with diagrams, worked examples, and the occasional interactive widget.

About

Role Controls Programmer
Industry BAS / Building Automation
Location Northeast U.S.
Verified 2026
Status Active

Hi, I'm a controls programmer based in the Northeast U.S. This is a side project I'm working on while exploring vibe coding. There's a genuine gap in easy reference websites and educational resources for this trade. This site started as just a way to have some easy reference tools in one place, but has expanded to include much more. Teaching those in the trade has been a passion of mine since I began to grow my own knowledge. With this project I aim to do that with a broader audience. I try to verify the accuracy of everything on this site the best that I can, but if anything is incorrect, please contact me and I will ensure I fix the accuracy issue. If there are any specific tools or topics you want to see covered, I want to hear about it!

Bug reports, tool requests, or feedback — get in touch.