Overview
The objective of this project is to control the Jandy heater using the RS485 interface.
Model: Jandy JXi Gas-Fired Pool and Spa Heater 260N
RS-4865 Interface
RS485 protocol, wiring & adapters
All pool equipment uses a half duplex RS485 protocol to comunicate between Control Panel, Keypads and inteligent Devices like Salt Water Generators, Variable Speed Pumps, Chemical feeders & some heaters.
There are a few main problems areas that you should have a basic understanding of, that can effect the performance.
RS485 Wiring and Termination (The majority of issues new people have are here)
RS485 USB Adapters and how they actually work in reguard to Pool equiptment. (this becomes very important on busy RS485 bus)
Wiring and Termination
Below is a basic diagram of an RS485 bus
As you can see, each device is connected to 3 wires (Data+, Data- & Ground), and there is a termination resistor at each end of the wiring (or bus).
The ground connection is their so the adapter has a referance point for the voltages in Data+ & Data-, and there is some level of circuit protection.
The termination resistors are their to prodide clear signals and stop reflection. Here is a detailed article on that
References
Reference | URL |
---|---|
Jandy Heater Manuals | https://www.jandy.com/en/products/heaters/jxi Installation: https://www.jandy.com/-/media/zodiac/global/downloads/h/h0574300.pdf Installation Code Handbook: http://www.tagengineering.ca/wp-content/uploads/2015/02/B149-1handbook.pdf |
Jandy-Aqualink RS485 Protocol | https://github.com/sfeakes/AqualinkD/wiki/Jandy-Aqualink-RS485-protocol |
AqualinkD - Opensource Software | https://github.com/sfeakes/AqualinkD |
AqualinkD - Wiki | https://github.com/sfeakes/AqualinkD/wiki |
Controlling RS485 devices | https://www.troublefreepool.com/threads/controlling-rs485-slave-devices-heater-pump-swg-directly-with-pi.221088/ |