Lake Shore Model 331 Temperature Controller User’s Manual
1.2 SPECIFICATIONS
Table 1-3. Input Specifications
Sensor
Temperature
Coefficient
Input Range
Excitation Current
Display
Resolution
Measurement
Resolution
Electronic Accuracy
Electronic
Control
Stability
11
Diode
negative
0 V to 2.5 V
10 µA ±0.05%
12,13
100 µV
10 µV
±80 µV ±0.005% of rdg
±20 µV
negative
0 V to 7.5 V
10 µA ±0.05%
12,13
100 µV
20 µV
±80 µV ±0.01% of rdg
±40 µV
PTC RTD
positive
0
Ω
to 500
Ω
1 mA
14
10 m
Ω
2
m
Ω
±0.004
Ω
±0.01% of rdg
±4 m
Ω
positive
0
Ω
to 5000
Ω
1 mA
14
100 m
Ω
20
m
Ω
±0.04
Ω
±0.02% of rdg
±40 m
Ω
NTC RTD
negative
0
Ω
to 7500
Ω
10 µA ±0.05%
14
100 m
Ω
40
m
Ω
±0.1
Ω
±0.04% of rdg
±80 m
Ω
Thermocouple
positive
±25 mV
NA
1 µV
0.4 µV
±1 µV ±0.05% of rdg
15
±0.8
µV
positive
±50 mV
NA
1 µV
0.4 µV
±1 µV ±0.05% of rdg
15
±0.8
µV
11
Control stability of the electronics only, in an ideal thermal system
12
Current source error has negligible effect on measurement accuracy
13
Diode input excitation can be set to 1 mA – refer to Paragraph 4.4.2
14
Current source error is removed during calibration
15
Accuracy specification does not include errors from room temperature compensation
Thermometry
Number of inputs
2
Input configuration
Each input is factory configured for either diode/RTD or thermocouples
Isolation
Sensor inputs optically isolated from other circuits but not each other
A/D resolution
24-bit
Input accuracy
Sensor dependent – refer to Input Specifications table
Measurement resolution Sensor dependent – refer to Input Specifications table
Maximum update rate
10 readings/s on each input (except 5 readings/s on input A when configured
as thermocouple)
User curves
Room for twenty 200-point CalCurves™ or user curves
SoftCal™
Improves accuracy of DT-470 diode to ±0.25 K from 30 K to 375 K; improves
accuracy of Platinum RTDs to ±0.25 K from 70 K to 325 K – stored as user
curves
Math
Maximum, Minimum, and Linear Equation (Mx + B) or M(x+B)
Filter
Averages 2 to 64 input readings
Table 1-4. Sensor Input Configuration
Diode/RTD
Thermocouple
Measurement type
4-lead differential
2-lead, room temperature compensated
Excitation
Constant current with current reversal for
RTDs
NA
Supported sensors
Diodes: Silicon, GaAlAs RTDs: 100
Ω
Platinum, 1000
Ω
Platinum, Germanium,
Carbon-Glass, Cernox™, and Rox™
Most thermocouple types
Standard curves
DT-470, DT-500D, DT-670, PT-100, PT-
1000, RX-102A, RX-202A
Type E, Type K, Type T, AuFe 0.07%
vs. Cr, AuFe 0.03% vs. Cr
Input connector
6-pin DIN
Ceramic isothermal block
1-6
Introduction
