Vaisala AQT530, Configuration Manual

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c[2] c[0] c[3] c[1] c[6] c[4] c[7] c[5]
3141h
3332h
31h
33h
41h
32h
‘2’ ‘A’ ‘3’ ‘1’
n
n + 1
n
n + 2
n + 1
n + 3
Modbus
registers
Modbus
byte stream
Serial number string (8 characters):
“A1234567”
‘6’ ‘4’ ‘7’ ‘5’
3534h
3736h
n + 2
n + 3
35h
37h
34h
36h
n + 4
n + 6
n + 5
n + 7
32h 41h 33h 31h 36h 34h 37h 35h
Figure 4 Byte order for string fields
6.5 Modbus register addresses for
AQT530
The following register addresses are available in AQT530. The register addresses are:
• R = Read only
• RW = Read/write
• W = Write only
Table 37 Modbus register addresses
Address RW Type Unit Register
count Description
0x0000 R int16 ppb 1 Nitrogen dioxide (NO
2
) concentration in parts
per billion (ppb) with linear correction
• For a value without linear correction, use
register 0x006C
• For µg/m
3
value, use register 0x0066
0x0001 R int16 ppb 1 Sulfur dioxide (SO
2
) concentration in parts per
billion (ppb) with linear correction
• For a value without linear correction, use
register 0x006D
• For µg/m
3
value, use register 0x0067
Chapter 6 – Modbus interface description
45