Modbus bits and decoder

[Rene Mulder]

Hi,

I'm trying to make some software for my fancoils. The plan is to make the fancoil run on high speed when there is nobody in the room or when the temperature set point is 3°C lower then the measured tempreature.

So far so good, got allmost all the modbus addres working eexcept for the one adres dthat is used to red/write for operting the fancoil.
I think the fancoil sends out a binairy code(?) wich one i then should read out through a decoder. (its a 16 bit, so i would need some block to split the signal)Found out how that should be working thanks to google.

But for some reason i can't get any data from the modbuss adress.. I tried every function, with the checkboxes below it checked and unchecked.

See below how the register is explaned.




I made a modbuss, analogue sensor with the adress 201:



Am i using the wrong sensor, should it be a actor ? Can't imagine and actor is about 0 - 1.

Anyone got some leads I could follow ?

[Tico]

What value is displayed when the address is reduced by -1 (ie. set address to 200)?

[Labmaster]

addresses -1 might not be an option as the addresses in the table starts already at 0.

But if i look at the output of the register 201 in your screenshot i think this is correct. (value 0)
ich you look at the description a value 0 (all bits 0) would say:
PRG: Automatic
LOCK: Keyboard enabled
Stby: Normal Operation

This look like the standard values to me.

in a next step you should try to modify the Value on Register 201 with a modiified value, lets say with a different PRG Mode.
Setup a Modbus Aktor (with the same config as works already when reading) then write a value of 1 to it (what should set the system to silent)
or 3 (setting it to maximum)

Check the written value reading it back (with the sensor)

[Jan W.]

Am i using the wrong sensor, should it be a actor ? Can't imagine and actor is about 0 - 1.

No, the sensor looks to be O.K., but you also need an actor with the same modbus address to send any values to the fancoils.

The correction option in your last screenshot is only useful e.g. for a temperature that is represented as an integer by multiplying the actual value with 10: 21,5°C would be represented as 215. Leave the correction values as they are (1 stays 1 and 10 stays at 10, so nothing is changed).

At first you have to split the output from your sensor 'operating mode' e.g. with a modulo block (with 4 as the divisor) to get the 'PRG' (from 0 to 3). Then you may use a radiobuttons block to visualize the status values from 0 to 3 with a meaningful name and allow changes. That output would be added to the other settings (Stdby and Lock) and used as an input for the actor for 'operating mode'. For testing purpose, you may assume that Stdby and Lock are 0 (as in your screenshot) and just use the output from the radiobuttons as an input for the actor.

[Rene Mulder]

Thank you all so much! I was thinking way too hard. 😅 I got it working on one fan coil now. I will be ready tomorrow.