OTGW no Boiler communication

This Forum is about the Opentherm gateway (OTGW) from Schelte

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ChrisW
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OTGW no Boiler communication

Post by ChrisW »

Hello All,

I have bought a new OTGW from kiwi-electronics and the soldered the OTGW.
When finished i connected it to my laptop and powered it up OTmonitor showed me that the diagnostics firmware is present and operational.
So i flashed the gateway (4.2.5) firmware. and connected it in between my thermostat (Remeha iSence, version 19) and my Boiler (Remeha Avanta 28C)

Otmonitor responded that the Thermostat is connected and working fine set time works also.
But he cannot find the Boiler also OTGW does not start communicating with the Boiler.

What could be the problem I have tried the troubleshooting steps on webpage otgw.tclcode and almost everything looks fine. I will put the test result into this topic later today.

Anyone has a suggestion?
Raspberry Pi 3 Model B, Raspbian+Domoticz V3.5877, RF-Link R44, OTGW 2.4.5, iSence v19, Avanta 28C
ChrisW
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Re: OTGW no Boiler communication

Post by ChrisW »

Power supply
Check 1:
The first thing to check is the power supply. Start out with the gateway unplugged from mains power, thermostat and boiler disconnected, and the IC's removed from their sockets. Now measure the resistance between the two terminals of X3. This should be in the order of kΩs. Check for short circuits if it is lower, or broken connections if it is higher.
Answer 1: Passed.
I must guess but X3 is the mains power I measure 2,98 kΩ.
Check 2:
Now that you have verified that the device will not blow out a circuit breaker, you can connect it to mains power. Be careful not to touch any of the parts that have 220 Volts on them. Check for 5V +/- 1% between pins 5 and 14 of IC1 and pin 15 and 16 of IC2.
Answer 2: Failed.
I don’t have IC2 for rs232 so ill only check IC1 and has 5,91V if it should be 1% then it should be between 4,95V and 5,05V.
But how to correct this problem?
Check 3:
Also make sure the polarity is correct. You should get a positive voltage if you put the black probe on the pin mentioned first and the red probe on the second one.
Answer 3: Passed.

Opentherm interfaces

Check 4:
Next measure the voltage on X1. This should produce a value somewhere between 18V and 34.5V. Anything higher means a risk of blowing out IC3. The polarity is not important.
Answer 4: Passed.
X1 volt measurement 22,8V
Check 5:
If the voltage is correct you can measure the current between the two terminals of X1. It should be between 5mA and 9mA. If you don't have a current setting on your multimeter you can hook up a 100Ω resistor to X1 and measure the voltage on X1. If you remember your high school physics you have probably already figured out that the voltage should be between 0.5V and 0.9V. Change the value of R11 if the current is not within the expected limits. A higher resistor value results in less current.
Answer 5: Passed.
X1 current measurement 6,27mA.
Check 6:
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 (1.7V and 2.3V across a 100Ω resistor). Deviations can be corrected by changing the value of R12. You increase the current by lowering the resistor value. Don't start manipulating R12 until the correct value of R11 has been determined (see above) because R11 influences both the low and high current values while R12 only affects the high current value.
Answer 6: Passed.
X1 current measurement 20,1mA.
Check 7:
If opto-coupler OK1 was not yet installed, remove the mains power and plug OK1 into its socket. Make sure it is placed the right way around. Now use two pieces of wire to connect X1 to X2 and plug the mains power back in. You should now find a voltage between 15V and 18V on X2 (and X1).
Answer 7: Passed.
X1 volt measurement 17,2V
Check 8:
If you connect pin 2 of the IC1 socket to VDD (e.g. pin 14), the voltage on X2 should drop to between 5V and 7V.
Answer 8: Passed.
X1 volt measurement 6,18V
Check 9:
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).
Answer 9: Unknown if it passed or failed?
Volt measurement between IC1:18 and IC1:5 – 0V when 3 and 5 are open.
Volt measurement between IC1:18 and X1:0 – 0V when 3 and 5 are open.
Volt measurement between IC1:18 and IC1:14 – 5,65V when 3 and 5 are open.
Volt measurement between IC1:18 and IC1:5 – 198,2mV when 3 and 5 are closed.
Volt measurement between IC1:18 and X1:0 – 198,2mV when 3 and 5 are closed.
Volt measurement between IC1:18 and IC1:14 – 4,86V when 3 and 5 are closed.
When finished, remove the wires between X1 and X2. Do not continue until all of the above checks have passed.

USB interface.
Remove the mains power again and place IC1 into its socket. Beware that IC1 is oriented the other way around from IC2. Connect the gateway to your PC.
Start the OTmonitor program and configure the connection via Options → Connection. For the RS232 and USB versions, you should choose "Serial port" and then select the correct serial port. Then click connect. Make sure the icon in the bottom right-hand corner of the main window shows an active connection: Note that the icon only shows that the program has successfully accessed the serial port/USB device. It provides no proof that the whole path to the gateway is in working order. Close the configuration window and access the Log tab.
Check 10:
If your PIC has been loaded with the latest gateway firmware, you should see a message saying "OpenTherm Gateway 4.2" when you reapply the mains power to the gateway. If you see only garbage appearing on the screen, there may be a baud rate mismatch.
Answer 10: Passed.
OpenTherm Gateway 4.2.5 received and a bunch more every second as described later.
Make sure you have configured your terminal emulator program correctly. If you see only some of the characters (like "OpenThery 4.2"), your serial cable could be too long. Gateways bought from the web shop usually come with the diagnostic firmware loaded. In that case you should expect "Opentherm gateway diagnostics - Version 1.0". OTmonitor will automatically pop up its diagnostics window when it sees this message.
Check 11:
If you see none of the above and you have checked your connection to the PC, verify that the PIC is really running. You should measure the following voltages on IC1: pin1=1.25V, pin2=0V, pin3=4.5V, pin4=5V, pin8=5V, pin9=5V, pin10=5V, pin11=5V, pin12=5V, pin13=5V, pin17=3.0V. If you are running the gateway firmware and have LEDs attached to the device, you should see them flash briefly about a second after applying power to the gateway.
Answer 11: Partly Failed.
I didn’t buy LED’s so I have to measure the volt on the Pins:
Pin 1 – 1,24V
Pin 2 – 4,88V
Pin 3 – 5,05V

Pin 4 – 5,05V
Pin 8 – 3,36V
Pin 9 – 5,05V
Pin 10 – 5,05V or 4,88V it jumps between these two values.
Pin 11 – 5,05V or 4,88V it jumps between these two values.
Pin 12 – 5,05V
Pin 13 – 5,05V
Pin 17 – 2,73V
The remainder of these troubleshooting instructions presume that the gateway is running the latest gateway firmware. If you have the diagnostics firmware loaded, you can take this opportunity to run a few of the diagnostics (and note down the results in case you need to report them later). When you are happy with the results, obtain the latest version of the gateway firmware and load it into the gateway using the File → Firmware upgrade option of OTmonitor.
Check 12:
The gateway should detect that no thermostat is connected and report "Thermostat disconnected". A few seconds later it starts generating opentherm messages every second, which it reports as R00000000. In addition to the actual report, OTmonitor will provide a time stamp and translate the message to a slightly more human readable version.
Answer 12: Passed.
Yes every second this message appears.
Check 13:
When serial transmission from the gateway to the PC is working, you can try to send a free format command to the gateway via Options → Miscellaneous (also accessible with the F7 key). If you type and enter "PR=B" you should get the date and time the firmware was built. For version 4.2 that is supposed to be "10:04 30-12-2014" ("12:31 02-02-2012" for version 2.1).
Answer 13: Passed.
20:55:24.076751 PR: B=17:59 20-10-2015
Raspberry Pi 3 Model B, Raspbian+Domoticz V3.5877, RF-Link R44, OTGW 2.4.5, iSence v19, Avanta 28C
hvxl
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Re: OTGW no Boiler communication

Post by hvxl »

Check 2: The webshop has a habit of providing a version of the 7805 that is not fit for the job. Ask them to send you a correct one.

Check 9: It's not unknown if it passed or failed. That's a big fat fail. 198,2mV is way below the required 1.25V or higher.

Check 11: Is irrelevant because check 10 already showed that the PIC is running.

You'll need to investigate why check 9 failed. Look at Q1, R1, R2, R3, and R4. Are they the right type/value and do you see the expected voltages on each of them?
Schelte
ChrisW
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Re: OTGW no Boiler communication

Post by ChrisW »

Thank you Schelte i will report back when i have more information.
Raspberry Pi 3 Model B, Raspbian+Domoticz V3.5877, RF-Link R44, OTGW 2.4.5, iSence v19, Avanta 28C
ChrisW
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Re: OTGW no Boiler communication

Post by ChrisW »

Corrected the resistors R2 and R3.

Check 9:
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).
Answer 9: Passed
Volt measurement between IC1:18 and IC1:5 – 0V when 3 and 5 are open.
Volt measurement between IC1:18 and X1:0 – 0V when 3 and 5 are open.
Volt measurement between IC1:18 and IC1:14 – 5,51V when 3 and 5 are open.
Volt measurement between IC1:18 and IC1:5 – 3,51mV when 3 and 5 are closed.
Volt measurement between IC1:18 and X1:0 – 3,48V when 3 and 5 are closed.
Volt measurement between IC1:18 and IC1:14 – 1,50V when 3 and 5 are closed.
Raspberry Pi 3 Model B, Raspbian+Domoticz V3.5877, RF-Link R44, OTGW 2.4.5, iSence v19, Avanta 28C
ChrisW
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Re: OTGW no Boiler communication

Post by ChrisW »

Finally, I got it working now.

But now I still need to convince Kiwi to send me the correct 7805.
Raspberry Pi 3 Model B, Raspbian+Domoticz V3.5877, RF-Link R44, OTGW 2.4.5, iSence v19, Avanta 28C
AlfredB
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Re: OTGW no Boiler communication

Post by AlfredB »

Hi there, can you please Tell how you managed to solve it? I'm having sort of the Same issue.

Thanks!
ChrisW
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Re: OTGW no Boiler communication

Post by ChrisW »

Hi i mixed up some resistors thats why my voltages where wrong.
Raspberry Pi 3 Model B, Raspbian+Domoticz V3.5877, RF-Link R44, OTGW 2.4.5, iSence v19, Avanta 28C
AlfredB
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Re: OTGW no Boiler communication

Post by AlfredB »

Hi,

Thanks for your reply. I've triple checked my resistors and they are all in the right place and the right value. Hoped that I had also mixed up one... I'll continue troubleshooting. Thanks again for your response.
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