Dear All i need to use a stuck pt100 3 wire on cr510 and after on cr1000. I have not buy this pt100 in campbell store
the pt100 operating range is -80°C at +160°C
I used short cut for release a wiring diagram and using a half bridge but my value are bad. approximatively -3650 or i need to measure ambiant temperature approximatively 20°C
Now i measure between H1 and L1 and i excite on E1.
maybe it's mistake?
I measured the ohmic resistance of the Pt100 and the value are 100ohm
I'm new user of pt100 and after reading the forum, i think i need to add resistor or more than 1 resistor but i don't konw the value and where i need to put them.
i have already use pt100 4WPB100 from campbell scientific and it worked very well.
while waiting to read you
regards
Hi fdec,
You are correct, you need to add a 10K ohm resistor. Jumper the resistor between VX1 and H. Because your PT100 has three wires, it probably has two wires of the same color, then a third of another color. The two wires of the same color are coming off the one side of the PT100 the the other color is coming of the other side.
For example BLACK 1st wire, BLACK second wire, RED third.
Put one BLACK in the H and the other BLACK in the L, put the RED in the AG or ground.
Here is a sample program for a CR3000. This will help you more with the CR1000.
'CR3000
PreserveVariables
Dim BattV
Dim PTemp_C
Ambient_1_Res, Ambient_2_Res
Units BattV = Volts
Units PTemp_C = Deg C
'Main Program
BeginProg
'Main Scan
Scan(1,Sec,1,0)
'Default Datalogger Battery Voltage measurement BattV
Battery(BattV)
'Default Wiring Panel Temperature measurement PTemp_C
PanelTemp(PTemp_C,_60Hz)
'Generic Half Bridge, 3 Wire measurements HBr3W()
BrHalf3W(Top_Res,1,mV5000,1,1,1,5000,True,0,_60Hz,10,0)
PRTCalc (Top,1,Top_Res,1,1.8,32)
Top=Round(Top,1)
BrHalf3W(Middle_Res,1,mV5000,3,1,1,5000,True,0,_60Hz,10,0)
PRTCalc (Middle,1,Middle_Res,1,1.8,32)
Middle=Round(Middle,1)
' BrHalf3W(Bottom_Res,1,mV5000,5,1,1,5000,True,0,_60Hz,10,0)
' PRTCalc (Bottom,1,Bottom_Res,1,1.8,32)
TCDiff (Bottom,1,mV20c,3,TypeE,PTemp_C,True ,0,_60Hz,1.8,32)
Bottom=Round(Bottom,1)
BrHalf3W(Solar_Res,1,mV5000,7,1,1,5000,True,0,_60Hz,10,0)
PRTCalc (Solar,1,Solar_Res,1,1.8,32)
Solar=Round(Solar,1)
BrHalf3W(Ambient_1_Res,1,mV5000,9,1,1,5000,True,0,_60Hz,10,0)
PRTCalc (Ambient_1,1,Ambient_1_Res,1,1.8,32)
Ambient_1=Round(Ambient_1,1)
BrHalf3W(Ambient_2_Res,1,mV5000,11,1,1,5000,True,0,_60Hz,10,0)
PRTCalc (Ambient_2,1,Ambient_2_Res,1,1.8,32)
Ambient_2=Round(Ambient_2,1)
'Call Data Tables and Store Data
CallTable
NextScan
EndProg
* Last updated by: sonoautomated on 10/24/2013 @ 4:58 PM *
Dear sonoautomated
thank you for your answer
this is true i have finally realease the measurement with a cr510 by adding a 10kohm resistor.
the difference between your code and my code are the multiplier.
but i think it's specific.
many thanks
regards
Hi fdec,
That is correct, good catch.
For a 1K ohm RTD you use 10 for the multiplier.
For a 100 ohm you use 100 for the multiplier.
Regards,