Pool Temperature Controller: Difference between revisions

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Details to follow.
This project is extensively detailed on the Parnell Engineering website [https://www.parnelleng.com/2021/02/a-wifi-enabled-red-lion-t48-temperature-controller-via-the-esp8266/ here].  The high-level details of the project are mirrored on this Wiki page.
 
=== Overview ===
 
The pool heater temperature controller was created to enhance control and monitoring over the unit used prior to 2020 (a Johnson Controls A419).
 
It provides thermostatic (on/off) control of the pool temperature via the boiler.
 
The key features are as follows:
 
* Clear indication of the sensed (feedback/input) temperature and setpoint (process) temperature on LED displays.
* Monitoring of the boiler operation (response to a 'call for heat').
* Provides network services via WiFi:
** A mobile-friendly website indicating operating status and temperatures.
** A monitoring-friendly service (i.e. JSON via HTTP) for monitoring trends, etc. via external software tools.
** On-call connection to an SMTP server to provide notification messages.
** The ability to post the present temperature to a website and/or digital signage (optional).
 
Furthermore, the following principles are used in its design:
 
* The core function (temperature control) shall be performed by a proven, durable controller.  In this case, a Red Lion T48 was chosen.
* The auxiliary function (monitoring) shall occur in a separate controller/core (NodeMCU/ESP8266) and shall NOT affect the core function in the event of failure or malfunction.
* While the device is connected to a restricted network (access limited via strict firewall rules), the monitoring controller should NOT be able to modify parameters on the temperature controller.  The reasons for this are two-fold:
** This adds additional security risk, as a security exploit could allow the boiler could be controlled remotely.
** There is no apparent need; changes to the setpoint are rare.  Changes can be done on-site via the front panel.


=== Drawings ===
=== Drawings ===
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[[File:FFSC-002 Temperature Controller.png|300px]]
[[File:FFSC-002 Temperature Controller.png|300px]]
=== Software ===
The software is stored on GitHub, in a private repository located at https://github.com/fairwayfarms/PoolHeaterControl.
As the source contains private information for WiFi and SMTP, it is not shared.  For FFSC members or staff: contact B&G for access to the repository.  In the future, a sanitized version may be made public.