Hi there,
I have a Temperature sensor from Omega (http://www.omega.com/temperature/pdf/SA1-RTD.pdf)
I followed the steps on ShortCut to config (I used one of the 3 wires examples) and the wiring U1 (red) U2 Black and Ground Black
Conneting on CR6, However the readings are off
can someone help please
Hi Rafael
in shortcut, you have to choose in the temperature section, the PT100 PRT with three wires and have either a 3-Wire Half Bridge terminal input module or at least a 10K accurate and stable temperature resistance.
For this second option in the CR6 manual you will find described all (code, range, wiring), for PRT measurements (3 or 4 wires) and specifications of the 10K (3 wires reference) or 100 ohm (4 wires reference) resistance.
Smile
The CR6 has an internal 100 Ohm reference for making resistance measurements. I don't see it supported in ShortCut, but you can use the Resistance3W instruction in CRBasic. That will directly provide the resistance of the PT100. You can then use the PRTCalc instruction to go from resistance to temperature.
Do you have an example of the code and how it should be wired?
Thank you
This is what I got:
'Main Program
BeginProg
Scan (1,Sec,0,0)
PanelTemp (PTemp,15000)
Battery (batt_volt)
Resistance3W (RTDTemp,1,mV5000,U1,2500,True ,0,60,1.0,0)
PRTCalc (CTemp,1,RTDTemp,1,1.0,0)
Thnaks guys, Jordan W. helped me
Great work! here is the code for the Omega 3 wires temp sensor
'Program: Basic RTD Program.CR6
'Date: 01/06/2017
'Author: Jordan Williams
'Wiring
' RTD - CR6 Port
' Red - U1
' Blk1 - U2
' Blk2 - Ground
'Declare Constants
Const Res_RTD_Zero = 100 'resistance of the RTD at 0 DegC (R0) - SA1-RTD is 100 Ohms at 0 DegC as per manual
'Declare Public Variables
Public Res_RTD 'RTD Resistance(RS)
Public Res_Ratio 'ratio of RTD resitance (RS) to RTD resitance at 0 DegC(R0) - RS/RO
Public Temp_RTD 'RTD Temp
'Main Program
BeginProg
Scan (1,Sec,0,0)
'Get RTD Resistance (RS)
Resistance3W (Res_RTD,1,mV5000,U1,2500,True ,0,60,1.0,0)
'Determine ratio of RTD resitance (RS) to RTD resitance at 0 DegC(R0)
Res_Ratio = Res_RTD / Res_RTD_Zero
'Calculate RTD Temp using PRTCalc - SA1-RTD is a IEC60751 - alpha = 0.00385
PRTCalc (Temp_RTD,1,Res_Ratio,1,1.0,0)
NextScan
EndProg
Thnaks guys, Jordan W. helped me
Great work! here is the code for the Omega 3 wires temp sensor
'Program: Basic RTD Program.CR6
'Date: 01/06/2017
'Author: Jordan Williams
'Wiring
' RTD - CR6 Port
' Red - U1
' Blk1 - U2
' Blk2 - Ground
'Declare Constants
Const Res_RTD_Zero = 100 'resistance of the RTD at 0 DegC (R0) - SA1-RTD is 100 Ohms at 0 DegC as per manual
'Declare Public Variables
Public Res_RTD 'RTD Resistance(RS)
Public Res_Ratio 'ratio of RTD resitance (RS) to RTD resitance at 0 DegC(R0) - RS/RO
Public Temp_RTD 'RTD Temp
'Main Program
BeginProg
Scan (1,Sec,0,0)
'Get RTD Resistance (RS)
Resistance3W (Res_RTD,1,mV5000,U1,2500,True ,0,60,1.0,0)
'Determine ratio of RTD resitance (RS) to RTD resitance at 0 DegC(R0)
Res_Ratio = Res_RTD / Res_RTD_Zero
'Calculate RTD Temp using PRTCalc - SA1-RTD is a IEC60751 - alpha = 0.00385
PRTCalc (Temp_RTD,1,Res_Ratio,1,1.0,0)
NextScan
EndProg