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Model 331 Autotuning Temperature
Controller |
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Features
Description Temperature Range  Technical
Information (370 Kb) |
| Features |
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- Two control loops
- Supports diodes,
Cernox™, Rox™, Thermox™, Carbon-Glass™, germanium, platinum,
rodium-iron, and thermocouple sensors
- Two sensor inputs
- Large vacuum
flourescent display
- One-touch access
to commonly used functions
- Model 330
emulation mode
- Current reversal
- Autotuning
- Alarms
- IEEE-488 and
RS-232 interface
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| Description |
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Intelligently designed and well-integrated for high performance and ease
of use,
the Model 331 Temperature Controllers are suitable for most cryogenic and
many higher temperature measurement and control applications. The Model 331 Temperature
Controllers combine the easy operation and unsurpassed reliability
of the Model 330 with improved sensor input and interface flexibility, including
compatibility with negative temperature coefficient (NTC) RTDs. Backed by
Lake Shore's tradition of excellence in cryogenic sensors and instrumentation,
the Model 331 Temperature Controllers set the standard for mid-price range temperature
control instruments.
The Model 331 Temperature Controllers are available in two versions. The Model 331S is
fully equipped for interface and control flexibility. The Model 331E shares measurement
and display capability with the Model 331S, but does not include the IEEE-488 interface,
relays, analog voltage output, or a second control loop. The purchaser's choice of Model
331S or 331E must be specified at time of order and cannot be reconfigured in the field. |
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| Sensor Inputs |
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The Model 331 Temperature Controllers are designed for high
performance with sensors across the 1.4 to over 1000 K temperature range and in difficult
sensing conditions, including magnetic fields. The Model 331 Temperature Controllers
feature two inputs, with a high-resolution 24-bit analog-to-digital converter and separate
current source for each input. Sensors
are optically isolated from other instrument functions for quiet
and repeatable sensor measurements. Sensor data from each input can be read up to ten
times per second, with display updates twice each second.
Standard temperature response curves for silicon diodes, platinum RTDs, and many
thermocouples are included. |
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| Up to twenty 200-point CalCurvesTM for Lake Shore calibrated sensors or
user curves can be loaded into non-volatile memory via computer interface or the
instrument front panel. A built-in SoftCalTM algorithm can also be used to generate curves
for silicon diodes and platinum RTDs, for storage as user curves. |
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| Factory-Configured Inputs |
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| Sensor inputs for both versions of the Model 331 are factory configured
and compatible with either diode/RTDs or thermocouple sensors. The purchaser's choice of
two diode/RTD inputs, one diode/RTD input and one thermocouple input, or two thermocouple
inputs must be specified at time of order and cannot be reconfigured in the field.
Software selects appropriate excitation current and signal gain levels when sensor type is
entered via the instrument front panel. |
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| The Diode/RTD input configuration is compatible with most diode and
negative and positive temperature coefficient RTDs. Current reversal eliminates thermal
EMF voltage errors for resistor sensors. |
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| The Thermocouple input configuration is compatible only with thermocouple
sensors. Room temperature compensation is included for any type of thermocouple in use.
Appropriate temperature response curves for many types of thermocouples are included;
temperature response curves may be entered as user curves for other thermocouples |
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Features
Description Temperature Range Technical Information (370 Kb) |
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| Temperature Control |
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| The Model 331E offers one and Model 331S two
proportional-integral-derivative (PID) control loops. A PID control algorithm calculates
control output based on temperature setpoint and feedback from the control sensor. Wide
tuning parameters accommodate most cryogenic cooling systems and many small high
temperature ovens. Control output is generated by a high-resolution digital-to-analog
converter for smooth continuous control. The first control loop drives heater output. Both
versions also include manual control mode. |
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| Heater output for the Models 331S and 331E is a well-regulated variable DC
current source. Heater output is optically isolated from other circuits to reduce
interference and ground loops. Heater output can provide up to 50 W of continuous power as
resistive heater load and includes two lower ranges for systems with less cooling power.
Heater output is short circuit protected to prevent instrument damage if the heater load
is accidentally shorted. |
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| The setpoint ramp feature allows smooth continuous changes in setpoint and
can also make the approach to a setpoint temperature more predictable. The zone feature
can automatically change control parameter values for operation over a large temperature
range; values for ten different temperature zones can be loaded into the instrument, which
will select the next appropriate value on setpoint change. |
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| Interface |
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| Interface Features
of Models 331S and 331E |
| Feature |
331S |
331E |
| Numeric keypad |
• |
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| Front panel curve entry |
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| Alarms |
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| Serial interface |
• |
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| IEEE-488 interface |
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| Two control loops |
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| Analog voltage output |
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| Relays |
• |
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| Model 331E is equipped with a serial RS-232C interface, while Model 331S
includes serial RS-232C and parallel IEEE-488 interfaces. Maximum reading rate can be
achieved with either interface. The most frequently used functions can be accomplished
from the instrument front panel with one or two keystrokes. Nearly every function on the
instrument front panel can also be performed via computer interface. Both versions include
Model 330 command emulation mode for drop-in interchangeability with Model 330 temperature
controllers in existing systems. |
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| High and low alarms for each input can be used in latching mode, requiring
user intervention before alarms reset. For the Model 331S, alarms can also be used in
conjunction with relays in non-latching mode, where alarms automatically reset when the
activation condition ends, to perform simple on-off control functions. Relay assignments
are configurable so that one relay may be assigned to each input or both assigned to a
single input for high/low control. |
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| The Model 331S's analog voltage output can be configured to send a voltage
proportional to temperature to a strip chart recorder or data acquisition system. The user
may select the scale and data sent to the output, including temperature, sensor units, or
linear equation results. Under manual control, the analog voltage output can also serve as
a voltage source for any other application. |
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| Autotuning |
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| he Model 331S and 331E autotuning feature automates the tuning process.
With its own measurements of system characteristics and based on characteristics of
typical cryogenic systems, the autotuning function computes proportional, integral, and
derivative setting values. On the Model 331S, the autotune function tunes one control loop
at a time. Because setting an inappropriate heating range is potentially dangerous to some
loads, the Model 331S and 331E autotuning feature does not attempt to automate that step
of the tuning process. |
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| SoftCal™ |
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| Lake Shore's SoftCal™ algorithm for silicon diode and platinum RTD
sensors is a good solution for applications that need more accuracy than a standard sensor
curve but not traditional calibration. SoftCal™ uses the predictability of a standard
curve to improve an individual sensor's accuracy around a few known temperature reference
points. Both versions of the Model 331 generate SoftCal™ curves. |
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| Configurable Display |
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| Both versions of the Model 331 include a bright vacuum fluorescent display
that simultaneously displays up to four readings. Display data includes input and source
annunciators for each reading. All four display locations can be configured by the user.
Data from either input may be assigned to any of the four locations; the user's choice of
temperature, sensor units, and maximum, minimum, or linear equation results can be
displayed. Heater range and control output as current or power can also be continuously
displayed for immediate feedback on control operation. |
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Features
Description Temperature Range Technical Information (370 Kb) |
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| Model 331 Temperature Range |
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| Diodes |
Model |
Useful Range |
| Silicon Diode |
DT-470 |
1.4 - 475 K |
| GaAlAs Diode |
TG-120 |
1.4 - 475 K |
| Positive Temperature
Coefficient RTDs |
| 100 W Platinum
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PT-100 |
30 - 800 K |
| Rhodium-Iron |
RF-800-4 |
1.4 - 400 K |
| Negative Temperature
Coefficient RTDs |
| Germanium |
GR-200A-1000 |
2 - 100 K |
| Germanium |
GR-200A-250 |
1.2 - 40 K |
| Carbon Glass™ |
CGR-1-500 |
3 - 325 K |
| Cernox™ |
CX-1050 AA or SD |
3.5 - 325 K |
| Cernox™ |
CX-1030 AA or SD |
2 - 325 K |
| High Temperature
Cernox™ |
CX-1030 AA or SD |
2 - 420 K |
| Rox™ |
RX-102A |
2 - 40 K |
| Rox™ |
RX-202A |
3 - 40 K |
| Thermox™ |
TX-104-GB |
110 - 325 K |
| Thermocouples |
| Type K |
9006-006 |
3.2 - 1500 K |
| Type E |
9006-004 |
3.2 - 930 K |
| Type T |
9006-008 |
3.2 - 670 K |
| Chromel-AuFe 0.07% |
9006-002 |
1.4 - 610 K |
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| Single excitation
current may limit the low temperature range of NTC resistors. |
| *Sensors sold
separately |
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| Model 331
Specifications |
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| Thermometry |
| Number of Inputs |
2 |
| Input Configuration |
Each input is factory
configured for either diode/ RTD or thermocouples |
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Diode / RTD |
Thermocouple |
| Measurement Type |
Four-lead differential
with current reversal |
Two-lead, room
temperature compensated |
| Excitation |
Constant Current |
NA |
| Supported
Sensors |
Diodes: Silicon, GaAlAs
RTDs: 100 W Platinum,
100 W Platinum, Germanium,
Carbon-Glass, Cernox™, Rox™, Thermox |
Most
thermocouple type |
| Standard Curves |
DT-470, DT-500D,
DT-600, PT-100, PT-1000, RX-102A, RX-202A |
Type E, Type K, Type
T,AuFe 0.07% Vs CH, AuFe 0.03% Vs CH |
| Input Connector |
6-pin DIN |
Ceramic isothermal
block |
| Isolation |
Sensor inputs optically
isolated from other circuits but not each other |
| A/D Resolution |
24 bit |
| Input Accuracy |
Sensor dependent; see
Sensor Input Performance chart |
| Measurement Resolution |
See Sensor Input
Performance chart |
| Maximum Update Rate |
10 readings/s on each
input (except 5 readings/s on input A when configured as thermocouple) |
| User Curves |
Room for 20 200-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 |
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| Control |
| Control Loops |
2 on 331S, 1 on 331E |
| Control Type |
Closed loop digital PID
with Manual Heater or open loop |
| Tuning |
AutoTune (one loop at a
time), PID, PID zones |
| Control Stability |
Sensor dependent; see
Sensor Input Performance chart |
| PID
Control Parameters |
| Proportional (Gain) |
0 – 1000 with 0.1
setting resolution |
| Integral (Reset) |
1 – 1000 (1000/s)
with 0.1 setting resolution |
| Derivative (Rate) |
1 – 200% with 1%
resolution |
| Manual Heater |
0 – 100% with
0.01% setting resolution |
| Zone Control |
10 temperature zones
with P, I, D, Manual Heater, and Heater Range |
| Setpoint Ramping |
0.1 to 100 K/min |
| Protection |
Curve temperature
limits, power up heater off, short circuit protection |
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Loop
1 |
Loop
2 |
| Heater Output Type |
Variable DC current
source |
Variable DC voltage
source |
| Heater Output D/A
Resolution |
18 bit |
16 bit |
| Max Heater Power |
50 W |
1 W |
| Max Heater Output
Current |
1 A |
0.1 A |
| Heater Output
Compliance |
50 V |
10 V |
| Heater Output Ranges |
3 decade steps in power
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1 |
| Heater Load Type |
Resistive |
Resistive |
| Heater Load Range |
10 W to 100 W
recommended |
100 W minimum
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| Heater Load for Max
Power |
50 W |
100 W |
| Heater Noise (<1
kHZ) RMS |
50 µV +
0.01% of output voltage |
< 0.3
mV |
| Isolation |
Optical
isolation between output and other circuits |
None |
| Heater Connector |
Dual banana |
Detachable terminal
block |
| Loop 1 Full Scale
Heater Power at Typical Resistance |
Heater
Resistance |
Heater
Range |
Heater
Power |
10 W |
Low
Med
High |
100mW
1 W
10 W |
25 W |
Low
Med
High |
250mW
2.5 W
25 W |
50 W |
Low
Med
High |
500mW
5 W
50 W |
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| Front Panel |
| Display |
2 line by 20 character,
9 mm character height, vacuum fluorescent display |
| Number of reading
displays |
1 to 4 |
| Display Units |
K, °C, V, mV, W |
| Reading Source |
Temperature, sensor
units, max, min, and linear equation |
| Display Update Rate |
All readings twice per
second |
| Temperature Display
Resolution |
0.001° between 0° -
99.999°, 0.01° between 100° - 999.99°, 0.1° above 1000° |
| Sensor Units Display
Resolution |
Sensor dependent, to 5
digits |
| Other Displays |
Setpoint, Heater Range,
and Heater Output (user selected) |
| Setpoint Setting
Resolution |
Same as display
resolution (actual resolution is sensor dependent) |
| Heater Output Display |
Numeric display in
percent of full scale for power or current |
| Heater Output
Resolution |
1% |
| Display Annunciators |
Control Input, Remote,
Alarm, Tuning, Ramp, Max, Min, Linear |
| Keypad |
20 full travel keys,
numeric and specific functions |
| Front Panel Features |
Front panel curve
entry, display brightness control, keypad lock-out |
| Interface |
| IEEE-488
Interface (331S) |
| Features |
SH1, AH1, T5, L4, SR1,
RL1, PP0, DC1, DT0, C0, E1 |
| Reading Rate |
To 10 readings/s on
each input |
| Software Support |
LabView driver (consult
factory for availability) |
| Serial Interface |
| Electrical Format |
RS-232C |
| Max Baud Rate |
9600 BAUD |
| Connector |
DE-9 |
| Reading Rate |
To 10 readings/s on
each input (at 9600 baud) |
| Special Interface
Features |
Model 330 command
emulation mode |
| Alarms |
| Number |
4, high and low for
each input |
| Data Source |
Temperature, Sensor
Units, Linear Equation |
| Settings |
High Setpoint, Low
Setpoint, Deadband, Latching or Non-Latching, Audible On/Off |
| Off Actuators |
Display annunciator,
beeper, relays |
| Relays
(331S) |
| Number |
2 |
| Contacts |
Normally Open (NO),
Normally Closed (NC), and Common (C) |
| Contact Rating |
30 VDC at 5 A |
| Operation |
Activate relays on
high, low, or both alarms for either input or manual |
| Connector |
Detachable terminal
block |
| Analog Voltage
Output (331S) |
| Scale |
User selected |
| Update Rate |
10 readings per second |
| Data Source |
Temperature, Sensor
Units, Linear Equation |
| Settings |
Input, source, top of
scale, bottom of scale, or manual |
| Range |
±10 V |
| Resolution |
0.3 mV |
| Accuracy |
±2.5 mV |
| Minimum
Load Resistance |
100 W (short
circuit protected) |
| General |
| Ambient Temperature |
15 - 35 °C at rated
accuracy. 10 - 40 °C at reduced accuracy |
| Power Requirement |
100, 120, 220, 240 VAC,
+5% -10%, 50 or 60 Hz, 120 VA |
| Size |
217 mm W x 90 mm H x
317 mm D (8.5” x 3.5” x 14.5”), half rack |
| Weight |
4.77 kg (10.5 lbs) |
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| Ordering Information |
| Part number |
Description (Input
configuration cannot be changed in the field.) |
| Standard Temperature
Controllers, all features included |
| 331S |
Two Diode / Resistor
Inputs |
| 331S-T1 |
One Diode / Resistor
Input, One Thermocouple Input |
| 331S-T2 |
Two Thermocouple Inputs
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| Economy Temperature
Controllers, all features of the 331S are included except IEEE-488 interface, relays,
analog voltage output, and a second control loop |
| 331E |
Two Diode / Resistor
Inputs |
| 331E-T1 |
One Diode / Resistor
Input, One Thermocouple Input |
| 331E-T2 |
Two Thermocouple Inputs
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Features
Description Temperature Range Technical Information (370 Kb) |
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Advanced Research Systems, Inc.
7476 Industrial Park Way, Macungie, PA 18062
Tel: 610 967 2120 Fax: 610 967 2395
E mail ars@arscryo.com |
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