OTGW does not communicate with boiler (OK1A errors)

[joukio]

hi all,

got a OTGW for half a year now and suddenly it doesn't look like it's working anymore. Setup is as follows:

isense thermostate
remeha tzerra boiler
opentherm gateway (rs232 model)
domoticz beta release (latest from today, 17xx).

I noticed in domoticz that all the boiler and thermostat figures weren't updated. I disabled the otgw in domoticz and took over with screen (no X running on that server, so otgw monitor only working in webmode). The gateway was only showing me commands from the thermostat but not from the boiler. So when I got home I removed the gateway and made a direct connection and boiler and thermostat were working again. But, the gateway wasn't.

I hooked up the gateway to a laptop with X running, flashed the firmware to the diagnostics firmware and when I ran test nr 4 it showed me the below results:

Enter test number: 4
OK1A high-to-low: ### Error
OK1A low-to-high: ### Error
OK1B high-to-low: 6us
OK1B low-to-high: 4us

I didn't have the time to run the tests with boiler and thermostat connected (besides the fact that wouldn't be easy to do within the closet it sits in) but my conclusion was that the gateway interface to the boiler is broken. At least that's what is looks like to me. Could someone give me a hand with debugging it a bit further?

kind regards

Jouk

[hvxl]

What does test #5 report? You can shift the opto-coupler (OK1) 2 pins toward the center of the board and rerun test #4 and #5 to verify if the problem is with the opto-coupler, or somewhere else. You may also shift it 2 pins in the opposite direction (from its initial location) and run test #4 and #5 again. You did loop X1 and X2 together for test #4, right?

[joukio]

Well, I did the test a couple of times and the error stayed or there was no loopback interface detected. Then I reseated the optocoupler in its normal position and it worked with the diagnostics firmware.
What I did noticed is that if I run test 4 a couple of times in a row OK1B high-to-low gives an error in some tests, but most tests run fine. Will flash the latest beta firmware back in and hook it up tomorrow.

For the record, below the output of test 4 and 5

Enter test number: 4
OK1A high-to-low: 9us
OK1A low-to-high: 11us
OK1B high-to-low: ### Error
OK1B low-to-high: 4us

Opentherm gateway diagnostics - Version 1.1

1. LED test
2. Bit timing thermostat
3. Bit timing boiler
4. Delay symmetry
5. Voltage leves
6. Idle times

Enter test number: 4
OK1A high-to-low: 9us
OK1A low-to-high: 11us
OK1B high-to-low: 4us
OK1B low-to-high: 4us

Opentherm gateway diagnostics - Version 1.1


1. LED test
2. Bit timing thermostat
3. Bit timing boiler
4. Delay symmetry
5. Voltage leves
6. Idle times

Enter test number: 5
Thermostat: 2.06
Boiler: 0.00
Reference: 1.21

will post once I have more information.

regards Jouk