Campbell CR1000

Section 7. Installation
A terminal input module can be used to complete the circuit in figure PT100 in
Three-Wire Half-Bridge
(p. 242). Refer to the appendix Signal Conditioners (p. 647)
for information concerning available TIM modules.
Figure 64. PT100 in Three-Wire Half-Bridge
CRBasic Example 51. PT100 in Three-wire Half-bridge
'This program example demonstrates the measurement of a 100-ohm PRT using a three-wire half
'bridge. See FIGURE. PT100 in Three-Wire Half-Bridge
(p. 242) for wiring diagram.
Public Rs_Ro
Public Deg_C
BeginProg
Scan(1,Sec,0,0)
'BrHalf3W(Dest,Reps,Range1,SEChan,ExChan,MPE,Ex_mV,True,0,250,100.93,0)
BrHalf3W(Rs_Ro,1,mV25,1,Vx1,1,2200,True,0,250,100.93,0)
'PRTCalc(Destination,Reps,Source,PRTType,Mult,Offset)
PRTCalc(Deg_C,1,Rs_Ro,1,1.0,0)
NextScan
EndProg
7.9.15.4 PT100 in Four-Wire Full-Bridge
Example shows:
• How to measure a PRT in a four-wire full-bridge
Advantages:
• Uses half as many terminals configured for analog input as four-wire half-
bridge.
Example PRT Specifications:
• α = 0.00392 (PRTType 2)
This example measures a 100 ohm PRT in a four-wire full-bridge, as shown in
figure PT100 in Four-Wire Full-Bridge
(p. 244), using CRBasic instruction
242