Node.JS Read/write serial communication, bitwise

[alveman]

I am trying to read/write values to a heat pump. How the communication works is described at https://rago600.sourceforge.net/ and in these examples.

For example:
Register 020B is sixteen bit number.
Let's write it in binary form 0000 0010|0000 1011
Now we can mark 7 groups from the end 00|0000100|0001011
And now we have this number in 7 bit form 00 04 0B

We have received temperature 00 04 38
Let's write 7 bit numbers in binary form 0000000|0000010|0111000
We will mark 8 bit delimiters 00000001|00111000
It is: 138(hex) 312(dec)
In that case temperature is 31.2C

We have received temperature 03 7C 1D
Let's write 7 bit numbers in binary form 0000011|1111100|0011101
We will mark 8 bit delimiters 11111110|00011101
It is: FE1D(hex) 65053(dec)-483(signed integer)
Received temperature is -48.3C

I have succeeded in decoding the values coming from the heat pump with this function but cannot get the reverse to work ie from dec to 7 bit hex.

var data = Buffer.from(msg.payload);
var decoded_int = (data[1] << 14) + (data[2] << 7) + data[3];
var decoded_buffer = Buffer.from([decoded_int & 0xff, decoded_int >> 8]);
var decoded = decoded_buffer.readInt16LE();
return { "decoded": decoded };

 

[Antero360]

I am trying to read/write values to a heat pump. How the communication works is described at https://rago600.sourceforge.net/ and in these examples.

For example:
Register 020B is sixteen bit number.
Let's write it in binary form 0000 0010|0000 1011
Now we can mark 7 groups from the end 00|0000100|0001011
And now we have this number in 7 bit form 00 04 0B

We have received temperature 00 04 38
Let's write 7 bit numbers in binary form 0000000|0000010|0111000
We will mark 8 bit delimiters 00000001|00111000
It is: 138(hex) 312(dec)
In that case temperature is 31.2C

We have received temperature 03 7C 1D
Let's write 7 bit numbers in binary form 0000011|1111100|0011101
We will mark 8 bit delimiters 11111110|00011101
It is: FE1D(hex) 65053(dec)-483(signed integer)
Received temperature is -48.3C

I have succeeded in decoding the values coming from the heat pump with this function but cannot get the reverse to work ie from dec to 7 bit hex.

var data = Buffer.from(msg.payload);
var decoded_int = (data[1] << 14) + (data[2] << 7) + data[3];
var decoded_buffer = Buffer.from([decoded_int & 0xff, decoded_int >> 8]);
var decoded = decoded_buffer.readInt16LE();
return { "decoded": decoded };

Hi there,
Is there a particular reason you would need this knowledge?

 

[alveman]

I am trying to program an interface between my heat pump and Node Red to be able to control the heat pump according to the prevailing electricity price.