We had still some work to do on our heatingplant, we had some flow issues to fix to let the boiler do a good job.
After we did this, we noticed that the boiler keeps burning on low flame. Even if the setpoint was high, the boiler stays at low flame.
We found out that we need to write a value at this register as well:
14 maximum relative modulation level setting
By default all values are 0, even this one.
When you give customers some advice about controlling their boiler with unipi, you should tell them this:
When a boiler needs to be controlled at setpoint:
write modulating supply setpoint at register 1
write fixed setpoint of maximum load of the boiler on register 14 (100%)
When a boiler needs to be controlled at cappacity:
write fixed supply setpoint at register 1 (90°)
Write modulating value of requested load setpoint on register 14
@Havor I do not have any experience with Stepper motors connected via Modbus so I cannot tell... But implementing any TCP or RS485 Modbus device is pretty straight forward in Mervis. You just need to map the registers you wish to read from/write to the Modbus device...
what is the best way to detect that the boiler and the thermostat are online
you could use the statistical registers, eg. 2004 and 2006 (or 2104, 2106)
does it make sense to switch the gateway between monitor and active mode (e.g. in normal condition, i rely on the thermostat, but in case the regular scedule needs to be overruled, i switch to active mode (with the thermostat still connected)
of course, it is only about the coil configuration of the coil whether the gateway is repeating the communication to the boiler from thermostat or no...
Experience in steering opentherm boilers, do's and dont's...
cannot tell much here, but definitely all pros!
Neuron/Neuron software has a higher level interface where i could integrate simply and just set measured and expected temperatures? (Can always consider to switch to Neuron, after all including heating control is a rather advanced
actually all you need is to set the boiler on or off and set the expected setpoint. The logic of those has to be done in your application. In Mervis there are function block like equithermal curve and time scheduler to help you write your own "thermostat"