Campbell Scientific CR3000 Micrologger - Manual (Page 270)

Section 7. Installation
270
Conclusion: Limit is imposed by the resistance of the PRT. If resistance
of 5 PRTs is expected to sum below 5000 Ω (below an average of ≈0°C),
5 PRTs can be accommodated.
Figure 84: PT100s with current excitation
CRBasic Example 62. PT100s with Current Excitation
'See FIGURE. PT100s with Current Excitation (p. 270) for wiring diagram.
Public Rs(3), Rs_Ro(3)
Public Deg_C(3)
Const Ro = 100
Public z
BeginProg
Scan (1,Sec,0,0)
'Resistance(Dest,Reps,Range,InputChan,IExChan,MPE,ExuA,RevEx,RevDiff,
' SetTime,Integ,Mult,Offset)
Resistance (Rs(),3,mV200,1,Ix1,3,1000,True,True,0,250,1.0,0)
For z = 1 To 3
Rs_Ro(z) = Rs(z) / Ro
Next z
'PRTCalc(Dest,Reps,Source,PRTType,Mult,Offset)
PRTCalc (Deg_C,3,Rs_Ro(),1,1.0,0)
NextScan
EndProg