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Model 24C Cryogenic Temperature Controller

Specifications


UpUp Model 24C General Specifications

User Interface

Display Type:240x64 graphics TFT LCD with LED back-light.
1x font is 4mm, 2x is 8mm.

Number of Inputs Displayed: One to Four.

Keypad: Sealed Silicon Rubber.

Temperature Display: Six significant digits, auto-ranged.

Display Update Rate: 0.5 Seconds.

Display Units: K, C, F or native sensor units.

Display Resolution: User selectable to seven significant digits.

Input Channels

There are four input channels, each of which may be independently configured for any of the supported sensor type.

Sensor Connection: 4-wire differential. DIN-6 Connector.

Sensor Types: See Supported Sensor Section.

Thermocouple: External option. Up to four supported.

Sensor Selection: Front Panel or remote interface.

Input Configurations: See input specifications table.

Bridge Modes: Constant-Current or Constant-Voltage.

Bridge type: Ratiometric resistance bridge.

AC Excitation Frequency: 7.5Hz bipolar square wave.

Voltage Excitations: 10mV, 1.0mV and 300uV. Minimum excitation current is 50nA.

DC Offset: <30nA.

Sample Rate: 15Hz per channel, all sensor types.

Digital Resolution: 24 bits.

Measurement Accuracy: See input specifications table.

Measurement Drift: 15ppm/°C.

Isolation: Input channel circuits are electrically isolated from all other internal circuitry but not from each other.

Measurement Filter: 0.5, 1, 2, 4, 8, 16, 32 and 64 Seconds.

Calibration Curves: Built-in curves for industry standard sensors plus eight user curves with up to 200 entries each. Interpolation is performed using a Cubic Spline.

CalGen™: Calibration curve generator fits any Diode or resistor sensor curve at 1, 2 or 3 user specified temperature points.

Status Outputs

Audible and Visual Alarms: Independent audible remote and visual alarms.

Relays: Two dry-contact relays. N.O. contacts available. Ratings are 125VAC @ 10A. Maximum switching power: 150W.

Status reported via Remote Interface: Sensor fault, Heater over temperature fault.

Control Outputs

Number of Independent Control Loops: Four.

Control Input: Any sensor input.

Loop Update Rate: 15Hz per loop.

Isolation: Control loop circuitry is electrically isolated from all other internal circuitry.

Control Type: PID table, Enhanced PID, Ramp or Manual.

Autotune: Minimum bandwidth PID loop design.

PID Tables: Six user PID tables available for storage of setpoint and heater range vs. PID and heater range. 16 entries/table.

Set-point Accuracy: Six+ significant digits.

Fault Monitors: Control loops are disconnected upon detection of a control sensor fault or excessive internal temperature.

Over Temperature Disconnect: Heater may be relay disconnected from user equipment when a specified temperature is exceeded on any selected input.


Loop #1 Primary Heater Output

Type: 50-Watt short circuit protected linear current source. Maximum compliance is selectable at 25V or 50V.

Ranges: Three output ranges of 1.0A, 333mA and 100mA full scale, which correspond to 50W, 5.0W and 0.5W.

Minimum Load: 10Ω in 25W setting, 40Ω in 50W setting.

Resolution: 1.0ppm of full-scale power (20 bits).

Readbacks: Heater output power, Heatsink temperature.

Loop #2 Heater Output

Type: 25-Watt, short circuit protected linear current source. Maximum output is 0.45A at 25V.

Ranges: Two output ranges of 25W and 2.5W into a 50Ω load.

Load Resistance: 50Ω for maximum output.

Minimum Load: 10Ω.

Resolution: 1.0ppm of full-scale power (20 bits).

Readbacks: Heater output power, Heatsink temperature.

Loop #3 and #4 Control Output

Loops #3 and #4 are analog voltage outputs that are intended to drive an external booster supply.

Output: User selectable at 10 or 5-Volt full scale..

Resolution: 1.0ppm of full-scale power (20 bits).

Connection: Detachable terminal block.

Remote Interfaces

Ethernet: Ethernet Local Area Network. Electrically isolated. TCP/IP and UDP servers provide remote control by using an ASCII command language. HTTP provides built-in web server. SMTP sends e-mail based on alarm conditions.

RS-232: Serial port is an RS-232 standard null modem. Data rates are 9600, 19,200, 38,400 and 57,200 Baud.

Optional IEEE-488 (GPIB): Full IEEE-488.2 compliant.

Optional USB: USB 1.1 and 2.0 compliant. Serial port emulation.

Remote Programming Language: IEEE-488.2 SCPI compliant.

LabVIEW™ drivers available for all interfaces.

Data Logging

Data logging is performed to an internal, 1,000 entry circular buffer and is time-stamped with a real-time clock. Buffer memory is non-volatile and will retain valid data without AC power.

User Setups

Four User Setups are available that save and restore the complete configuration of the instrument.

General

Ambient Temperature: 25°C ± 5°C for specified accuracy.

Mechanical: 8.5”W x 3.5”H x 12”D. One half-width 2U rack. Instrument bail standard, rack mount kit optional.

Weight: 9 Lbs.

Power Requirement: 100, 120, 220 or 240VAC +5% -10%. 50 or 60Hz, 150VA.

Conformity: European CE certified. RoHS, Lead Free.

Calibration: NIST traceable.

 

UpUpModel 24C Supported Sensors

A unique feature of the Model 24C is the use of a ratiometric AC resistance bridge to measure all types of sensors.

The AC excitation used with all resistor sensors (including Platinum RTDs) is a 1.625Hz bipolar square wave. This effectively eliminates DC offset errors including the thermal EMF induced offsets that often occur in cryogenic systems.

Positive Temperature Coefficient (PTC) resistor sensors including Platinum and Rhodium-Iron RTDs use the resistance bridge in it's constant-current, AC operating mode. Platinum RTD sensors use a built-in DIN standard calibration curve that has been extended to 14K for cryogenic use.

The Model 24C's resistance bridge is used in a constant-voltage AC mode to provide robust support for the Negative Temperature Coefficient (NTC) sensors commonly used by cryogenic applications. They include Ruthenium-oxide, Carbon-Glass, Cernox™, Carbon Ceramic, Germanium and several others. Since these sensors have a negative temperature coefficient, the use of a constant-voltage measurement method will reduce, rather than increase, power dissipation in the sensor as temperature decreases. By maintaining the lowest possible power level, sensor self-heating is minimized and useful temperature range is greatly increased.


page Listing of Supported Sensors

An additional advantage to constant-voltage excitation is that NTC resistors lose sensitivity in the upper part of their range. By auto-ranging excitation current to maintain a constant voltage, sensitivity and noise immunity in that range is also improved.

The excitation source in the Model 24C is continuously variable so there are no steps in sensor self-heating.

Diode sensors are supported over their full temperature range by using the bridge in a DC, constant-current mode. This mode provides the required 10µA DC sensor excitation and 0 to 2.25 volt input range


Thermocouple

Model 24C Supported Sensors
 
Temperature Range
Example Sensors
Diode 1.4 - 500K Cryo-con S950 / S900
SI-440, 430, 410
Lakeshore DT-670, 470
Platinum RTD 14 - 1200K Cryo-con CP-100
Cryo-con GP-100
Cryo-con XP-100
Cryo-con XP-1K
Rhodium-Iron 1.4 - 800K Oxford PHZ 0002

CLTS

4K to 300K

Vishay CLTS-2B

Germanium 200mK - 100K Lakeshore GR-200A
Carbon Glass™ 1.4 - 325K Lakeshore CGR-1-500
Cernox™ 200mK- 325K Lakeshore, all types
Carbon-Ceramic 200mK - 300K TMi-A1
Ruthenium-Oxide 200mK - 200K SI RO-600

1.4 to 1500K

All thermocouple types.

UpUp

Model 24C Input Specifications


 
Diode sensors
PTC resistor sensors
NTC resistor sensors Constant-Voltage mode
NTC Resistor Sensors Constant-Current mode

Thermocouple
(Option)

Excitation Mode
DC, Constant-Current
AC, Constant-Current
AC, Constant-Voltage
Constant-Current DC Resistance Bridge
DC voltage
Input Range
2.25V
750Ω,7.5KΩ and
75KΩ Full-Scale.
CLTS 300Ω
Minimum: 0.5Ω Maximum: 2.0MΩ
100K - 225KΩ
±70mV
Accuracy:
 % of Rdg + % of Range
0.005% + 0.0003%
0.01% + 0.0005%
14Ω to 30KΩ: 0.05% + 0.05%
0.5Ω to 2MΩ: 0.15% + 0.15%
0.005% ± 25Ω
0.05
Resolution:
  % of Range
0.00004%
0.0003%
0.0003%
0.00004%
0.0003%
Excitation Current
10µA DC
1.0mA, 100µA, 10µA
100mV, 10mV, 1.0mV
2.5mA to 50nA,
continuously variable
10µA DC
N/A

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Specifications subject to change without notice. ©Cryogenic Control Systems, Inc. 1998 - 2017