serialLoop logic

[micmoc95]

Hello Chris,

Two questions are bothering me.

First
serialLoop() is invoked from loop() with while (ModbusSerial.available()) serialLoop().
So when we enter serialLoop there’s always at least one byte read from modbus.
This code section is never executed, right ?

if (!ModbusSerial.available() && (millis() - lastSerialLoop) < 1000) {
// only run serialLoop if there is new data or last run was 1 sec ago
return;
}

Second
Suppose now, as this is my case, that preventCommunication() returns true. As ModbusSerial.available() returns true wasAvail will be set to true leading to leave serialLoop and getting stuck to "not talking to heater" ?

Thx for your help

[dumpfheimer]

Hi
Yes, the first one is a kind of a bug I introduced a few weeks ago while trying to optimize latency.

I don't understand what you mean with your second question. The "not talking to heater" part happens when there has been no recent room temperature received. WiFiVototrol then refuses to talk to the heater which causes an error on the heater and might revert it to another mode such as outside temperature lead control (depending on heater).

So, if there are bytes available in loop it will loop through serialLoop. If a message valid message is read it will check if any datapoint is preventing communication with the heater and will not proceed if so.

[micmoc95]

Thx for your answed.
After first boot when WifiVitotrol enters serialLoop (first character received from the boiler) for the first time, preventCommunication() returns true (maybe that’s the point).
So this code:

if (preventCommunication()) {
bool wasAvail = false;
while (ModbusSerial.available()) {
ModbusSerial.read();
wasAvail = true;
lastReadAt = millis();
}
if (wasAvail) {
strncpy(linkState, "Did not respond to heater because datapoint prevented it", LINK_STATE_LENGTH);
}
debugPrintln("not talking to heater");
return;
}
#endif

leaves me stuck with a down link state.
Maybe preventCommunication is faulty in my case.

Regards

[dumpfheimer]

preventCommunication is true and therefore prevents communications with the heater when there is no valid current room temperature. This is the case when the device has never received a temp since boot or after (if I remember correctly) 30 minutes. So you are required to send a current room temperature after boot to enable communication with the heater.

The reason is: I do not want the heater to keep raising / lowering the Vorlauftemperatur (target desired exit water temperature of the heater) to the maximum value if e.g. Home assistant (or any other "master") stops working. Rather the heater should revert to its default behaviour if it looses communication with the vitotrol, which is caused by preventCommunication.

Hope this clears things up a bit.

You can prevent this behaviour in the datapoint configuration if it does not suit your needs. I would be interested in why that is the case for you, though.

[micmoc95]

I understand the reason to prevent communication during actual behaviour. But my issue is on the very first exchange when the heater sends a request to ESP32 to get ils serial number.
As I replaced my Vitotrol 200 with the ESP there is no other trafic before the first exchange after boot so how can some room temperature be involved ?
When you say "YOU have to send à current room temperature" who is the YOU ?

[dumpfheimer]

The heater will continuously ping the Vitotrol and when it receives a pong it will read the serial number.
So preventing communication from the start will not cause any issues. My heat pump pings every few seconds, some older devices may need up to 5 minutes.

It is the Vitotrols task to communicate the current room temperature to the heater. WiFiVitotrol relies on something/someone external to transmit that temperature regularly. That can be you as in you for testing but would more likely be some automation or system that simply sends it periodically.

Without a current room temperature WiFiVitotrol will refuse to talk to the heater.

You can send the temperature via mqtt to virtualvitotrol/currentRoomTemperature/set or post it to eg /setCurrentRoomTemperature?val=23

[micmoc95]

OK Chris

But as my understanding the preventCommunication test is at the start of serialLoop.
When first message from heater is read byte per byte the reader returns from the loop and the message or any next message is never processed. The "not talking to heater" and "Did not respond to heater because datapoint prevented it" are printed for each message from heater. So the ESP never answers to heater request - pong or serial number enquiry -.
What am I missing ?

void serialLoop() {
if (!ModbusSerial.available() && (millis() - lastSerialLoop) < 1000) {
// only run serialLoop if there is new data or last run was 1 sec ago
return;
}
lastSerialLoop = millis();
// only speak to heater when no datapoint is preventing it
#ifndef FIND_DEVICE_ID
if (preventCommunication()) {
bool wasAvail = false;
while (ModbusSerial.available()) {
ModbusSerial.read();
wasAvail = true;
lastReadAt = millis();
}
if (wasAvail) {
strncpy(linkState, "Did not respond to heater because datapoint prevented it", LINK_STATE_LENGTH);
}
debugPrintln("not talking to heater");
return;
}
#endif

[dumpfheimer]

Thanks for clearing things up, @MarenB .
Be aware that /datasets has a kind of flawed logic in presenting data as the WiFiVitotrol project currently has no correct implementation of the 3F/BF commands Viessmann uses. However it does not look like there will be much more information extractable than outside temp, setpoints, and some states.

[micmoc95]

Even if I wait à few tens of minutes everything I can see is my heater asking for Vitotrol serial number on and on.
Maybe because I replaced my actual Vitotrol 200 with WifiVitotrol ?
My goal is to get fuel consumption and hours of heating to include then in Home Assistant’s energy panel.

[MarenB]

Does your heater accept the ESP as Vitotrol at least already or us complaining the remote wouldn't be available?
Mine didn't like the virtual one sent with SA 0x34, but with 0x38 it was ok.
What kind of heater do you have?

[MarenB]

Unless you want to send a current room temperature, it's probably easier to use the optolink interface to obtain burner power, operating hours, etc.
The current room temperature is the only application that actually requires to go via KM bus.

[micmoc95]

My heater is à fuel heater :

• Vitola 200 VB2A
• Vitoflame 100 VEM burner
• Vitotronic 200 K01B or K02B ? controller
• Vitotrol 200A wired remote command

It does not have an Optolink interface.
I will try using SA38 (Vitotrol 300).