Thermostat connection error

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Thermostat connection error

Postby Steek » Sun Jan 08, 2017 2:36 am

Hi,

I'm trying to get an DIY of the OTGW working, but I run into some problems.
I've connected the thermostat (Remeha iSense v27) and the boiler (Remeha Calenta), but the Thermostat is giving an F207 error (connection error).

I see the following messages in otMonitor:
Code: Select all
00:52:51.945942  T1002010B  Write-Data  Master configuration: 00000001 11
                               - Smart power: supported (1)
00:52:52.088312  BD002010B  Write-Ack   Master configuration: 00000001 11
                               - Smart power: supported (1)
00:52:52.948710  T1002010B  Write-Data  Master configuration: 00000001 11
                               - Smart power: supported (1)
00:52:53.096713  BD002010B  Write-Ack   Master configuration: 00000001 11
                               - Smart power: supported (1)
00:52:53.952104  T1002010B  Write-Data  Master configuration: 00000001 11
                               - Smart power: supported (1)
00:52:54.091814  BD002010B  Write-Ack   Master configuration: 00000001 11

These messages keep repeating.
At some point after a restart, the messages changed:

Code: Select all
01:02:18.232159  A5014E100  Write-Ack   Day of week and time of day: Sun 01:00
01:02:18.700482  T9014E100  Write-Data  Day of week and time of day: Sun 01:00
01:02:18.723477  R00300000  Read-Data   DHW setpoint boundaries: 0 0
01:02:18.855540  BC0303C28  Read-Ack    DHW setpoint boundaries: 60 40
01:02:18.898105  A5014E100  Write-Ack   Day of week and time of day: Sun 01:00
01:02:19.702160  T9014E100  Write-Data  Day of week and time of day: Sun 01:00
01:02:19.727846  R80310000  Read-Data   Max CH setpoint boundaries: 0 0
01:02:19.858763  B40315014  Read-Ack    Max CH setpoint boundaries: 80 20
01:02:19.900590  A5014E100  Write-Ack   Day of week and time of day: Sun 01:00
01:02:20.708859  T9014E100  Write-Data  Day of week and time of day: Sun 01:00
01:02:20.731916  R00740000  Read-Data   Burner starts: 0
01:02:21.075791  B40749888  Read-Ack    Burner starts: 39048
01:02:21.106827  A5014E100  Write-Ack   Day of week and time of day: Sun 01:00
01:02:21.717316  T9014E100  Write-Data  Day of week and time of day: Sun 01:00
01:02:21.743435  R80750000  Read-Data   CH pump starts: 0
01:02:22.069512  BC075AC58  Read-Ack    CH pump starts: 44120
01:02:22.095594  A5014E100  Write-Ack   Day of week and time of day: Sun 01:00
01:02:22.719786  T9014E100  Write-Data  Day of week and time of day: Sun 01:00
01:02:22.759151  R80760000  Read-Data   DHW pump/valve starts: 0
01:02:23.069169  B407628A0  Read-Ack    DHW pump/valve starts: 10400

But still a connection error..

I've followed the steps on the troubleshooting page and I have one value which might be off:
Measure the voltage on pin 18 of the IC1 socket with pin 3 left open and again when it is connected to ground. In the former case the voltage should be below 1.25V (it is actually expected to be 0V). In the latter case the voltage must be above 1.25V (and will probably be close to 5V).


This gives 0V and 1.85.

The rest of the values seems OK

I've also tried some diagnostics tests and test #4 (delay symmetry) gave an error about the interfaces not being looped (I've tried connecting X1 to X2 and also X1 -> X1 and X2 -> X2, but no luck).

Does anyone know what the problem could be? Or how I can proceed to investigate further?

PS:
I've got a version with an esp8266 for communication, an TracoPower TSR 1-2450 as replacement for the 7805 and 15V/AC 2VA iso 15V/AC 1.2VA

Regards
Steek
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Re: Thermostat connection error

Postby hvxl » Sun Jan 08, 2017 10:23 am

These logs indicate that pretty much everything works; serial interface, receiving messages from the thermostat, sending messages to the boiler, receiving responses from the boiler and sending responses back to the thermostat. Only the thermostat keeps repeating the same message (and shows an error). That is an indication that the thermostat doesn't understand the responses.

Changing the current on the thermostat line as needed for sending messages to the thermostat is the job of IC1 pin 3, R9, R12, Q4, and Q5. These are being verified by the checks in the first 2 paragraphs of the opentherm interfaces section of the troubleshooting instructions. Please carefully rerun those checks. It is not necessary to remove IC2 and OK1, only removing IC1 is sufficient. You will also have to disconnect the thermostat.

If the checks are still OK, please also measure the current on X1 with IC1 in place. (Remove the OTGW power before removing or replacing IC1.) The current should also be between 5mA and 9mA in this situation.

If you don't find any issues this way, please load the diagnostic firmware and run test #4.
Schelte
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Re: Thermostat connection error

Postby Steek » Sun Jan 08, 2017 2:09 pm

Hi,

Thanks for the quick reply.

Here are the results of the measurements:
Next measure the voltage on X1. This should produce a value somewhere between 18V and 34.5V.

Result: 25.5V-26.5V

If the voltage is correct you can measure the current between the two terminals of X1. It should be between 5mA and 9mA.

Result: 5.93mA

If you connect pin 3 of the IC1 socket to ground (e.g. pin 5), the current between the two terminals of X1 should be between 17mA and 23mA

Result: 19.8mA

If the checks are still OK, please also measure the current on X1 with IC1 in place. (Remove the OTGW power before removing or replacing IC1.) The current should also be between 5mA and 9mA in this situation.

Result: 6.1mA

test 4 of diagnostics:

Opentherm gateway diagnostics - Version 1.1

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

Enter test number: 4
### Error: Interfaces don't appear to be looped

I've tried the following combinations:
- X1-1 connected to X2-1 and X1-2 connected to X2-2
- X1-2 connected to X2-1 and X1-1 connected to X2-2
- X1-1 connected to X1-2 and X2-1 connected to X2-2

All with the same result:
### Error: Interfaces don't appear to be looped

How does the system recognize that the interfaces are connected? Could the problem be in this area?
Steek
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Re: Thermostat connection error

Postby hvxl » Sun Jan 08, 2017 3:38 pm

Steek wrote:How does the system recognize that the interfaces are connected? Could the problem be in this area?

It pulls both pins 3 and 4 low and then expects to see high levels on pins 17 and 18 within a reasonable amount of time (65ms).

Apparently that doesn't happen, which matches with the thermostat problems. As we already know everything else works and you have manually verified that pulling pin 3 low produces the expected current, there must be an issue with PIC output port RA4 (pin 3). If you're lucky its just a contact problem. Is pin 3 perhaps bent and doesn't actually go into the socket? Or is it a cheap socket that has a bent contact so it doesn't touch the IC pin? With IC1 in its socket do you measure a short circuit between pin 3 and the nearby lead of R9?

Before finally concluding that IC1 is damaged, also check that Q4 is a BC548 and Q5 is a BC558. I don't expect the wrong components would cause the symptoms you experience, but it's easily checked before getting a new PIC. I don't suppose you happen to have a spare one?

By the way, the loop should be one of the first 2 options you listed. The 3rd one will never work.
Schelte
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Re: Thermostat connection error

Postby Steek » Sun Jan 08, 2017 8:32 pm

If I measure the pin 3 and the lead of R9 withthe diode (beeper) test, I get a sound, so I guess the connection is fine when I look at the schematic.

I used the following components:
Q4: https://www.conrad.nl/nl/transistor-fai ... 63804.html
Q5: https://www.conrad.nl/nl/transistor-fai ... 62971.html

I don't have a spare PIC lying around, but if that seems to be the problem I can order a new one.
Steek
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Re: Thermostat connection error

Postby hvxl » Sun Jan 08, 2017 10:53 pm

Those are suitable components. But my question was more to double-check that you put the right component in the right place.

It is quite unusual for RA4 of the PIC to be defective, but we've pretty much ruled out all other possibilities. And Sherlock Holmes says: When you have eliminated all which is impossible, then whatever remains, however improbable, must be the truth.
Schelte
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Re: Thermostat connection error

Postby Steek » Wed Jan 11, 2017 9:24 pm

It was indeed the PIC.

I ordered a new one, and flashed the diagnostics firmware to it.
When running test #4 I got the following result:

Enter test number: 4
OK1A high-to-low: 10us
OK1A low-to-high: 19us
OK1B high-to-low: 5us
OK1B low-to-high: 6us

And after installing it between my boiler and thermostat, the termostat doesn't return an error, and with otMonitor I can read-out the data.

Thanks for helping!
Steek
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Re: Thermostat connection error

Postby hvxl » Fri Jan 13, 2017 10:15 pm

Great. Thanks for reporting back that it is in fact possible that only one PIC I/O port is damaged while everything else works fine. I did not expect that.
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