a. It looks like Atomic Base does not have a 120Ohm resistor integrated - it is needed for proper operation of rs485 (I have it in my device schematic). * Atomic RS485 Base does not have an integrated 120Ω terminal resistor inside. You can refer to the position in the diagram below to add a 120Ω resistor between the A/B lines. - If you have any 100-200 ohm resistor, give it a try.
b. Do you have TTL/Serial converter (similar to what is used to program ESP chops) If yes, I’d try to connect it to the atomic rs485 base to see if anything comes there - that will help you to isolate hardware vs software problem (although I think it is highly likely to be hardware).
I’m curious about this, as I also have an NPE-250A2 and using an RS485 Base as well, but with the Atom Lite (not S3 version) and it seems to work fine without a resistor…unless I’m missing something.
Then the only theory I have left is the variation between RS485 modules Or, perhaps, do you have anything else connected to the RS485 bus (unlikely I am guessing, but just in case)?
Normally, RS485 receivers should not work without proper resistor. Mystery that it works in your case…
Looking at the current schematics for the Atomic RS485 Base, it does show a resistor. Is the same unit mentioned above though, but I wonder if maybe that’s an update to newer ones
This is certainly interesting. My base is new (ordered new at least). I did try moving to the Atom Lite (not S3 version) and hit the same issue as with the S3 version. Did you have it wired the same way as in my picture?
Interested in an interface also. I have the following boiler working with a Navilink light. NHB-55H ultra-high efficiency heating boiler | Navien . If all sold out can I get a reccomended parts list ? ESP32, RS485 board and I’d like a splitter if possible so I can keep the Navilink light. Thanks.
Or, perhaps, do you have anything else connected to the RS485 bus (unlikely I am guessing, but just in case)?
