Max CH Temperature PS1 command

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Schampbakken
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Max CH Temperature PS1 command

Post by Schampbakken »

Hello,

i'm trying to read out data parallel with otmonitor and a python program, it's working quite fine. I have a question about how otmonitor get the info Max CH Temperature.
When i look at the PS1 string i get info like:

00000011/00000000,90.00,00000001/00000001,0.00,0/0,25.00,0.00,0.00,13.13,23.00,0.00,0.00,0.00,0/0,0/0,0.00,0.00,0,0,
MsgID0 ,1 ,6 ,14 ,15 ,16 ,17 ,18 ,24 ,25 ,26 ,27 ,28 ,48 ,49 ,56 ,57 ,116,117
The bold part should be the Max CH Temperature (MsgID57), but is 0.
In the PS1 string it is missing but when i look in OtMonitor log i see a message passing like:
AC0395A00 Read-Ack Max CH water setpoint: 90.00
Is there a way i can get this info also, or what is the trick otmonitor is doing?
Schampbakken
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Re: Max CH Temperature PS1 command

Post by Schampbakken »

I think I have to add the next lines to my question:
This is what i see in the log:
10:14:54.225932 T00390000 Read-Data Max CH water setpoint: 0.00
10:14:54.318330 BF0390000 Unk-DataId Max CH water setpoint: 0.00
10:14:54.329728 AC0395A00 Read-Ack Max CH water setpoint: 90.00

It looks to me the otmonitor is doing something with an Alternative Data-ID.
But what is the trick to catch the data of this.

When i do for example
http://localhost:8081/command?AA=56
i get a response:
AA: 56

in the log of otmonitor i then see these 2 lines pass after the AA=56
10:14:54.225932 T00390000 Read-Data Max CH water setpoint: 0.00
10:14:54.329728 AC0395A00 Read-Ack Max CH water setpoint: 90.00
hvxl
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Re: Max CH Temperature PS1 command

Post by hvxl »

This has been discussed before in this topic: viewtopic.php?f=75&t=12126.
Your boiler apparently doesn't support the Max CH water setpoint message, as can be seen from:
10:14:54.318330 BF0390000 Unk-DataId Max CH water setpoint: 0.00
That's why you get 0.00 in the PS=1 output.

The AC0395A00 message is generated by the OTGW (the first A indicates a message from the GW to the thermostat that differs from the message received from the boiler). The OTGW fills in the Max CH setpoint specified by the user, or the hard coded default Max CH setpoint, which is 90. But as this value is sent by the OTGW, it doesn't show in the PS=1 output.

MessageID 56 is the DHW setpoint, not the Max CH water setpoint. But most boilers either support both or neither. When adding an alternative message that the boiler does not support, the OTGW will delete it from the list of alternatives again. It doesn't keep requesting information that the boiler has indicated it won't provide.
Schelte
Schampbakken
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Re: Max CH Temperature PS1 command

Post by Schampbakken »

Ok thanks for the quick answer!!!

What is the reason OTGW is sending then the 90 to the thermostat?

My next question is when i send CS=XX (Control Setpoint) i see the value in OTmonitor,
in the OT log it is also passing, but it looks like the value of the thermostat is overwriting my value.
The PS message shows the value of the thermostat.
The Log is showing the next lines:
21:18:15.949039 Command (via websocket from ::1:60254): CS=60
21:18:15.966808 CS: 60.00
21:18:24.818519 T10012400 Write-Data Control setpoint: 36.00
21:18:24.840312 R10013C00 Write-Data Control setpoint: 60.00
21:18:24.910742 BD0013C00 Write-Ack Control setpoint: 60.00
21:18:24.927113 AD0012400 Write-Ack Control setpoint: 36.00

What can this cause?

I also tried the stand alone solution, i made a bridge on the thermostat input of the gateway. I tried to send the MM command.
13:50:12.281573 Command (via websocket from ::1:55514): 50=50
13:50:12.307060 MM: 50

I get a confirm from the gateway, but I don't think it is send to the boiler.

When i read the log on the place where the MsgID 14, should be the MsgID0 appears.
When nothing is connected to the thermostat terminals of the gateway (X1), the gateway will send a fixed series of opentherm messages to the boiler. The sequence is:
MsgID 0: Master and Slave Status flags
MsgID 25: Boiler flow water temperature
MsgID 1: Control Setpoint
UserDefined
MsgID 17: Relative Modulation Level
MsgID 27: Outside temperature
MsgID 28: Return water temperature
MsgID 14: Maximum relative modulation level setting
UserDefined
MsgID 0: Master and Slave Status flags
MsgID 25: Boiler flow water temperature
MsgID 1: Control Setpoint
MsgID 56: DHW Setpoint
MsgID 57: Max CH water Setpoint
UserDefined
MsgID 18: Water pressure in CH circuit
The only thing what is writen from the gateway to the boiler seems to be the control setpoint.
When I send now the control setpoint it looks like it is not overwriten, but in this solution i hoped to control the temperature with the max relative modulation level, cause then I can use a standard PID to control the boiler.
hvxl
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Re: Max CH Temperature PS1 command

Post by hvxl »

I haven't seen a thermostat that stops requesting certain MsgIDs when the slave returns Unk-DataId. But just to be sure certain functionality remains available, the OTGW will make up its own responses for selected requests.

Please read the normal operation section on the OTGW website to understand the meaning of the reports from the OTGW. Your log shows exactly what is supposed to happen: The thermostat requests 36 degrees. The OTGW changes that to 60 degrees in the message to the boiler. The boiler acknowledges that request. Finally the OTGW acknowledges the request that it received from the thermostat, which was for a control setpoint of 36 degrees. The OTGW should not send 60 degrees in the Write-Ack, because a thermostat may interpret that as a failure to do what was requested and repeat the original request for 36 degrees.

Why did you bridge the thermostat input when trying the stand-alone solution? You are not supposed to do that.

When you think the OTGW doesn't behave correctly, it would be much more helpful to show the logs of what you think is going wrong rather than the information from the web site that explains what is expected to happen. A possible reason for the OTGW not to send some messages is that the boiler has indicated that it doesn't support those messages, as explained on the web site just below the part you quoted. You should be able to find if that is the case in the statistics overview of OTmonitor. If the direction column for a certain message shows Unk, the boiler does not support that message. Note: You may not see unknown messages in stand-alone mode if OTmonitor hasn't been running since the last reset of the OTGW.

It is not usual to control the boiler using the max relative modulation level, but it should be possible. But that can only work if your boiler supports that message. So far my impression is that yours doesn't.
Schelte
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