Figure 81: pt100 in four-wire half-bridge, Crbasic example 59. pt100 in four-wire half-bridge – Campbell Scientific CR3000 Micrologger User Manual
Page 264
Section 7. Installation
264
calibrated multiplier. The 10 ppm/°C temperature coefficient of the fixed resistor
will limit the error due to its change in resistance with temperature to less than
0.15°C over the -10 to 40°C temperature range. Because the measurement is
ratiometric (R
S
/R
f
), the properties of the 10-kΩ resistor do not affect the result.
A terminal-input module (TIM) can be used to complete the circuit shown in
figure PT100 in Four-Wire Half-Bridge
(p. 264).
Refer to the appendix Signal
Conditioners
for information concerning available TIM modules.
Figure 81: PT100 in four-wire half-bridge
CRBasic EXAMPLE. PT100 in Four-Wire Half-Bridge
CRBasic Example 59. PT100 in Four‐Wire Half‐Bridge
'See FIGURE. PT100 in Four-Wire Half-Bridge
(p. 264)
for wiring diagram
Public
Rs_Ro
Public
Deg_C
BeginProg
Scan
(1,Sec,0,0)
'BrHalf4W(Dest,Reps,Range1,Range2,DiffChan1,ExChan,MPS,Ex_mV,RevEx,RevDiff,
' Settling, Integration,Mult,Offset)
BrHalf4W
(Rs_Ro,1,mV50,mV50,1,Vx1,1,4400,True,True,0,250,1.0111,0)
'PRTCalc(Destination,Reps,Source,PRTType,Mult,Offset)
PRTCalc
(Deg_C,1,Rs_Ro,1,1.0,0)
'PRTType sets alpha
NextScan
EndProg