RKI Instruments 71-0530, Operator'S Manual, Page: 70 / 72

70 • VOC Pro Transmitter
Appendix C: Modbus Register Map
Register Address 1: Hexadecimal numbers
Register Address 2: Decimal numbers
R/W: Read/Write capable data
R: Read-only data
FLOAT: Floating point number
ENUM: Enumeration
UINT: Unsigned integer
INT: Integer
BFLD: Bit Field
(*): Limited by precision
Register
Address
(Hex)
Register
Address
(Dec)
Data Description R/W Length Unit Valid Response(s)
1 1 Gas Reading R 2 FLOAT Numerical Gas Reading
3 3 Modbus Address R 1 UINT 0 – 247
4 4 Gas Type R 1 ENUM 0 – 26, see below
5 5 Unit Type R 1 ENUM 0 – 1, see below
6 6 Major Revision R 1 UINT 0 – 100
7 7 Minor Revision R 1 UINT 0 – 9
8 8 Mode of Sensor R 1 ENUM 0 – 7, see below
9 9 Voltage Reading R 2 FLOAT 12V – 35V
B 11 Fault Code R 1 ENUM 0 – 6, see below
C 12 Sensor Type R 1 ENUM 0-4, see below
E† 14† Relay 1 Setting R 2 FLOAT 1 – 32000
10† 16† Relay 2 Setting R 2 FLOAT 1 – 32000
16 22 Precision R 1 INT 0 – 3
17† 23† Relay Setting R 1 BFLD See Relay Setting Table
18 24 Days Since Last Zero R 1 UINT 0 – 60000
(>60000) Default to “Never”
19 25 Calibration Type R 1 ENUM 0 – 1
1A 26 Auto-Calibration Value R 2 FLOAT Numerical Gas Reading
1C 28 Days Since Last
Calibration
R 1 UINT 0-60000
(>60000) Default to “Never”
1E 30 Relay 1 State R 1 INT 0 – Relay Inactive
1 – Relay Active
1F 31 Relay 2 State R 1 INT 0 – Relay Inactive
1 – Relay Active
20 32 Relay 1 Reset R/W 1 INT Read as 0
Write 1 to reset Relay 1 state
21 33 Relay 2 Reset R/W 1 INT Read as 0
Write 1 to reset Relay 2 state