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VersaLog Data Loggers User’s Manual
Page 28
Channel and Sensor Specifications:
Connections:
Plugeable terminal block for four external channels, excitation
controls and alarm outputs
Channels: CH0: on-board thermistor (-40 ~ +70°C (-40 to + 158°F).
CH1 ~ CH4: three-wire/two-wire RTD.
VL-RTD-1: 20 ~ 400 Ohms (-200°C ~ 850°C)
Built-in equations for TCR 0.00385 and 0.00392
Resolution: 0.0018% (PT100: 0.02°C)
Accuracy:
Thermistor channel: +/- 0.2°C(0°C ~ 70°C)
RTD channels: +/- 0.015% @ 25°C
LRTD-1: +/-0.16°C @ 25°C
Choose Right Equation for RTD Sensors:
SiteView provides two factory RTD equations for measuring the temperature values:
RTD_TCR385:
This equation is for RTD sensor (PT100) with TCR 0.00385
Ω/Ω/°C between 0 and 100°C.
The temperature coefficients are:
A: 3.9083E-3 B: -5.775E-7 C: -4.183E-12
RTD_TCR392:
This equation is for RTD sensor (PT100) with TCR 0.00392
Ω/Ω/°C between 0 and 100°C.
The temperature coefficients are:
A: 3.9848E-3 B: -5.87E-7 C: -4E-12
SiteView also provides a custom equation called RTDEquation in case a RTD sensor has
different characteristics. The sample code looks like below and you can change TMAX,
TMIN, A, B, C and R0 to make it suit for your application:
// A custom equation for any RTD sensor
// Please change the following parameters based on the RTD types
const double TMAX = 850; //maximum temperature range in degree C
const double TMIN = -200; //minimum temperature range in degree C
//temperature coefficients. Change them accordingly
const double A = 3.9083E-3;
const double B = -5.775E-7;
const double C = -4.183E-12;
//resistance value in OHM at zero degree C
const double R0 = 100;
//A custom equation. Do not change equation name. Equation must return a value.
public double RTDEquation( double Input)
{
//Input is resistance in Ohm
double r = Input;
double t;