Campbell CS240 Product Manual page 33

CRBasic Example 3: CR1000X 2-wire configuration for measuring the CS240
'CR1000X Series
'Declare Variables and Units
Dim CS240X
Dim CS240Rs
Public CS240T_C
Units CS240T_C=Deg C
'Define Data Tables
DataTable(Hourly,True,-1)
DataInterval(0,60,Min,10)
Sample(1,CS240T_C,FP2)
EndTable
'Main Program
BeginProg
'Main Scan
Scan(5,Sec,1,0)
'CS240 (2-wire) Class A RTD Back of PV Module Temperature Sensor
'measurement 'CS240T_C'
BrHalf(CS240X,1,mV200,1,Vx1,1,350,True,0,60,1,0)
'Convert ratio to ohms and remove cable resistance
CS240Rs=CS240X*(1000+0.274)/(1-CS240X)-0.274
'Calculate temperature from resistance
PRTCalc(CS240T_C,1,CS240Rs/1000,1,1,0)
'Call Data Tables and Store Data
CallTable Hourly
NextScan
EndProg
CS240 and CS240DM PT-1000 Class A, Back-of-Module Temperature Sensors 27