In-Situ Aqua TROLL 400 Modbus and SDI-12 Reference Guide - Manual (Page 39)

Register Size
(registers)
Mode & Access Level
(R/W)
Data
Type
Description
Specific Conductivity
The default units for specific conductivity are uS/cm.
Conversion to other units is as follows.
mS/cm = uS/cm / 1000
Specific conductivity is calculated from actual conductivity and temperature using the following
equation.
SC = AC * (
β
0
+
β
1
T +
β
2
T
2
+ … +
β
7
T
7
) / (1 +
α (T-Tref))
Where T
ref
,
α, and β
0-7
are specified in the sensor calibration registers. The factory default coefficients
calculate specific conductivity per Standard Methods 2510B.
0554 2 R1 float Measured value, SC
0556 1 R1 ushort Parameter ID = 10
(specific conductivity)
0557 1 R1/W2 ushort Units ID
65 = microsiemens
per centimeter (default)
66 = millisiemens
per centimeter
0558 1 R1 ushort Data Quality ID
0559 2 R1/W3 float Off line sentinel value
(default = 0.0)
0561 1 R1 16 bits Available Units = 0x0003 (3)
Salinity
Salinity is calculated using actual conductivity and temperature.
0562 2 R1 float Measured value, S
0564 1 R1 ushort Parameter ID = 12 (salinity)
0565 1 R1/W2 ushort Units ID
97 = Practical Salinity Units
PSU (default)
0566 1 R1 ushort Data Quality ID
39