* SPICE netlist
R_Pt100 N002 0 {Rpt}
R2 N002 V+ {Rf4}
Rf1 N002 N001 {Rf1}
R4 0 N005 {Rf2}
R5 0 V- {Rf3}
V1 +5V 0 5
V2 0 -5V 5
I1 N005 N001 {Is}
XU1 V- N003 N004 V+ -18V 0 V_AI1 +18V AD8421 ;pnba IN-)RG1)RG2)IN+)VEE)REF)OUT)VCC
RG1 N003 N004 1800
V3 +18V 0 18
V4 0 -18V 18
V5V N006 0 5
R3 N006 ref 2k
R6 ref 0 3k
XU2 ref N007 N008 V_AI1 -18V 0 Vout +18V AD8421 ;pnba IN-)RG1)RG2)IN+)VEE)REF)OUT)VCC
RG2 N007 N008 4.2k
.step temp -10 50 10
;tran 0 1 0
.param Ro 100
.param A 3.9083*10**-3
.param B -5.775*10**-7
.param Rpt=Ro*(1+A*temp+B*temp**2)
.param Rf1 Rfio
.param Rf2 Rfio
.param Rf3 Rfio
.param Rf4 Rfio
.param Is 5m
.param Rfio 10
;op 0 1 0
.ac dec 10 1 1meg

* LTspice schematic (.asc)
Version 4
SHEET 1 1504 800
WIRE -656 -384 -752 -384
WIRE -480 -384 -576 -384
WIRE -704 -288 -704 -304
WIRE -656 -288 -704 -288
WIRE -480 -288 -480 -384
WIRE -480 -288 -576 -288
WIRE 0 -272 -48 -272
WIRE 640 -272 640 -288
WIRE 640 -272 624 -272
WIRE 752 -272 752 -288
WIRE 752 -272 736 -272
WIRE -752 -256 -752 -384
WIRE -480 -256 -480 -288
WIRE 640 -256 640 -272
WIRE 752 -256 752 -272
WIRE 0 -240 -32 -240
WIRE 208 -192 176 -192
WIRE -656 -144 -704 -144
WIRE -480 -144 -480 -176
WIRE -480 -144 -576 -144
WIRE -32 -144 -32 -160
WIRE 0 -144 -32 -144
WIRE -704 -128 -704 -144
WIRE 0 -112 -48 -112
WIRE -752 -48 -752 -176
WIRE -656 -48 -752 -48
WIRE -480 -48 -480 -144
WIRE -480 -48 -576 -48
WIRE -480 -16 -480 -48
WIRE 16 160 -112 160
WIRE 16 176 16 160
WIRE 256 192 208 192
WIRE 256 224 224 224
WIRE -112 240 -112 160
WIRE 16 272 16 256
WIRE 48 272 16 272
WIRE 464 272 432 272
WIRE 16 288 16 272
WIRE 224 320 224 304
WIRE 256 320 224 320
WIRE 256 352 208 352
WIRE -112 384 -112 320
WIRE -48 384 -112 384
WIRE 16 384 16 368
WIRE 16 384 -48 384
WIRE -48 400 -48 384
FLAG -704 -304 V+
FLAG 624 -272 0
FLAG 640 -368 +5V
FLAG 640 -176 -5V
FLAG -704 -128 V-
FLAG 736 -272 0
FLAG 752 -368 +18V
FLAG 752 -176 -18V
FLAG -48 -272 V+
FLAG -48 -112 V-
FLAG 112 -128 0
FLAG -480 -16 0
FLAG 48 272 ref
FLAG -48 400 0
FLAG 208 -192 V_AI1
FLAG 32 -288 +18V
FLAG 32 -96 -18V
FLAG 368 336 0
FLAG 464 272 Vout
FLAG 288 176 +18V
FLAG 288 368 -18V
FLAG 208 352 ref
FLAG 208 192 V_AI1
SYMBOL res -496 -272 R0
SYMATTR InstName R_Pt100
SYMATTR Value {Rpt}
SYMBOL res -560 -304 R90
SYMATTR InstName R2
SYMATTR Value {Rf4}
SYMBOL res -560 -400 R90
SYMATTR InstName Rf1
SYMATTR Value {Rf1}
SYMBOL res -560 -64 R90
SYMATTR InstName R4
SYMATTR Value {Rf2}
SYMBOL res -560 -160 R90
SYMATTR InstName R5
SYMATTR Value {Rf3}
SYMBOL voltage 640 -384 R0
SYMATTR InstName V1
SYMATTR Value 5
SYMBOL voltage 640 -272 R0
SYMATTR InstName V2
SYMATTR Value 5
SYMBOL current -752 -176 R180
SYMATTR InstName I1
SYMATTR Value {Is}
SYMBOL OpAmps\\AD8421 32 -192 R0
SYMATTR InstName U1
SYMBOL res -48 -256 R0
SYMATTR InstName RG1
SYMATTR Value 1800
SYMBOL voltage 752 -384 R0
SYMATTR InstName V3
SYMATTR Value 18
SYMBOL voltage 752 -272 R0
SYMATTR InstName V4
SYMATTR Value 18
SYMBOL voltage -112 224 R0
SYMATTR InstName 5V
SYMATTR Value 5
SYMBOL res 0 160 R0
SYMATTR InstName R3
SYMATTR Value 2k
SYMBOL res 0 272 R0
SYMATTR InstName R6
SYMATTR Value 3k
SYMBOL OpAmps\\AD8421 288 272 R0
SYMATTR InstName U2
SYMBOL res 208 208 R0
SYMATTR InstName RG2
SYMATTR Value 4.2k