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
Connecting to a Remote Pool-Off-Spa Selector (3-Wire Connection) (See b above)
NOTE: When a fireman’s switch is being utilized and “hi-lo-com” is selected, the heater will fire automatically when the contacts close even if the user interface on the heater is off.
Configure the Control Panel
NOTE: The display will revert back to OFF 1 minute after the last key press.
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)
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
See:
Table 1 of the manual you posted lists the connections as
Red: +10V
Black: SD+
Yellow: SD-
Green: GND
Serial port runs at 9600 baud, no parity, 1 stop bit, 7-bit chars only.
DTR must be HIGH. RTS must be LOW to receive and HIGH to transmit!
All packets are formatted as follows:
DLE STX <data> <checksum> DLE ETX
Sometimes NULs are sent before and after the packet.
note: if DLE occurs in packet it is escaped as DLE NUL!!!
<data> := <dest><command><args>
<checksum> := the 7-bit sum of bytes DLE, STX and <data>
<dest> := a single byte representing destination for packet
<command> := a single byte with command for destination device
<args> := optional string of bytes for command data
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 |
*** Serial Adaptor Information | |
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/ |