3712
Temnerature Control (continued)
Temnerature Control
Temperature Rangelo
Resolution and ~ccuracyl'
Temperature
-20 "C
0 "C
20
"C
50 "C
LM335 Setting Accuracy
AD590 Setting Accuracy
Short Term
Stability12
Long Term Stability13
Sensor Type
Usable Thermistor Range
LM335 Voltage
LM335 Bias
AD590 Current
AD590 Bias
Thermistor Sensing Current
Temperature Calculation Methods
Thermistor:
-99 OC to +199 OC
-20 OC to
+70
OC with typical 10K thermistor
Resolution
M.l OC
39.1 OC
M.1 OC
M.2 OC
39.2 OC
ko.2 OC
H.O
1 OC or better, over
1
hr.
M. 1 OC or better, over 24 hours
Accuracy
M.2
OC
M.2OC
33.2 OC
f0.2 OC
2-wire thermistor; AD590 current
type;
or LM3
3
5
voltage
type
25
n
to
450
m,
typ.
V(25 OC)
=
2980 mV; VT
=
10 mVI0K over rated sensor
range
1
mA
1(25 OC)
=
298.2 pA; IT
=
1 pAl°K over rated sensor range
+8 VDC
10 pA or 100 pA (user selectable)
AD590 or LM335 calibrated with
two-point
method.
Termistors are calibrated by storing three constants of the
Steinhart-Hart equation in internal non-volatile memory.
1R
=
(Cl
*
lo-))
+
(C2
*
)(In
R)
+
(C3
*
10-')(ln
R)3
(T
in Kelvin)
T
=
C1
+
C2
*
(V
/
(10 mVI0K)
-
273.15)
T=C1 +C2
*
(I/(l
pA/"K)
-
273.15
''~en~~erature control range depends primarily on the type of thermistor and
TE
module used. The range can be
extended higher and lower by selecting appropriate components. See Appendix B for more details.
"Accuracy figures quoted are typical for a 10
kR
thermistor and 100 pA source current setting (10 pA source
current settmg at -20 "C. Accuracy figures are relative to calibration standard.
Both resolution and accuracy are
dependent on the user defined configuration of the instrument.
120\.er
any
1
hour interval, controlling an LDM3112 mount
@
25 OC, with
a
10K thermistor on 100 pA setting.
l3O\,er
any
2-1
hour interval, controlling an LDM-4412 mount
@
25 "C, with a 10K thermistor on 100 pA setting.
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com
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