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www.vtsgroup.com Page 12 of 16 ver. 2.0 (11.2021)
4.1.1. DEV_ID_REG (addr=11=0x000B) – read only
Bit no.
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
name
DEV[4..0]
HV[1..0]
OPTIONS[4..0]
0
0
T[1..0]
This register is used to store device ID. Meaning of bits:
DEV[4..0] = b11000 – fixed value meaning “air parameter sensors”
HV[1..0] – value 0..3 – hardware version
OPTIONS[4..0] – values 0..31 – device type
b10000 – CO2 transducer with MH-Z19B sensor
T[1..0] – value 0..3 – type
0 – duct type
1 – room type
2, 3 - reserved
CO2 duct sensor in basic hardware version returns the value b1100000100000000=0xC100.
4.1.2. SOFT_VER_REG (addr=12=0x000C) – read only
Bit no.
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
name
N[3..0]
A[3..0]
B[3..0]
REV[3..0]
Software version is represented as a sting of 4 characters: N.ABrev
where
N, A, B are digits in the the 0..9 range
rev (with values 0..9) is a letter in the range ‘a’...’j’.
Examples:
0x0000 represents software version: 0.00a; 0x4321 → 4.32b ; 0x2345 → 2.34f
4.2. Protocol functions
CODE
Name
0x03 (dec 3)
Reading N x 16-bit registers
0x06 (dec 6)
Writing single 16-bit registers
0x10 (dec 16)
Writing N x 16-bit registers