Cryo-con 24C User Manual

User's Guide

Model 24C

Cryogenic Temperature Controller

CRYOGENIC CONTROL SYSTEMS, INC.

P.O. Box 7012
Rancho Santa Fe, CA 92067
Tel: [phone]
Fax: [phone]
www.cryocon.com

Copyright 2010- 2014
Cryogenic Control Systems, Inc.
All Rights Reserved.

Printing History

Edition 3e.

Certification

Cryogenic Control Systems, Inc. (Cryo-con)
certifies that this product met its published
specifications at the time of shipment. Cryo-con
further certifies that its calibration
measurements are traceable to the United
States National Institute of Standards and
Technology (NIST).

Warranty

This product is warranted against defects in
materials and workmanship for a period of one
year from date of shipment. During this period
Cryo-con will, at its option, either repair or
replace products which prove to be defective.

For products returned to Cryo-con for warranty
service, the Buyer shall prepay shipping
charges and Cryo-con shall pay shipping
charges to return the product to the Buyer.

However, the Buyer shall pay all shipping
charges, duties, and taxes for products returned
to Cryo-con from another country.

Warranty Service

For warranty service or repair, this product must
be returned to a service facility designated by
Cryo-con.

Limitation of Warranty

The foregoing warranty shall not apply to
defects resulting from improper or inadequate
maintenance by the Buyer, Buyer supplied
products or interfacing, unauthorized
modification or misuse, operation outside of the
environmental specifications for the product, or
improper site preparation or maintenance.

The design and implementation of any circuit on
this product is the sole responsibility of the
Buyer. Cryo-con does not warrant the Buyer's
circuitry or malfunctions of this product that
result from the Buyer's circuitry.

In addition Cryo-con does not warrant any
damage that occurs as a result of the Buyer's
circuit or any defects that result from Buyer­supplied products.

Notice

Information contained in this document is
subject to change without notice.

Cryo-con makes no warranty of any kind with
regard to this material, including, but not limited
to, the implied warranties of merchantability and
fitness for a particular purpose.

Cryo-con shall not be liable for errors contained
herein or for incidental or consequential
damages in connection with the furnishing,
performance, or use of this material. No part of
this document may be photocopied,
reproduced, electronically transferred, or
translated to another language without prior
written consent.

Trademark Acknowledgement

CalGen® and Cryo-Con® are registered
trademarks of Cryogenic Control Systems, Inc.
All other product and company names are
trademarks or trade names of their respective
companies.

Safety

The Model 24C does not contain any user
serviceable parts. Do not open the enclosure.
Do not install substitute parts or perform any
unauthorized modification to the product. For
service or repair, return the product to Cryo-con
or an authorized service center.

Cryo-con Model 24C

Table of Contents

Introduction................................................................................................. 1

Sensor Inputs.......................................................................................1

Control Loops....................................................................................... 2

User Interface...................................................................................... 2

Remote Control....................................................................................4

Preparing the controller for use..................................................................7

Supplied Items..................................................................................... 7

Verify the AC Power Line Voltage Selection.........................................7

Apply Power to the Controller...............................................................8

Installation............................................................................................9

Initial Setup and Configuration.............................................................11

A Quick Start Guide to the User Interface...................................................17

Specifications, Features and Functions......................................................21

Specification Summary........................................................................ 21

Performance Summary........................................................................27

Input Channel Characteristics..............................................................30

Control Loop Outputs...........................................................................34

Remote Interfaces................................................................................ 36

Rear Panel...........................................................................................37

Mechanical, Form Factors and Environmental.....................................38

Front Panel Operation................................................................................41

The Keypad.......................................................................................... 41

The Front Panel Display.......................................................................46

Front Panel Menu Operation......................................................................51

Instrument Setup Menus......................................................................51

Basic Setup and Operation.........................................................................73

Configuring a Sensor........................................................................... 73

Using NTC Sensors............................................................................. 74

Using PTC resistor sensors.................................................................76

Downloading a Sensor Calibration Curve.............................................77

Autotuning............................................................................................80

Temperature Ramping.........................................................................85

Cryocooler Signature Subtraction.........................................................88

Using an external power booster..........................................................91

Using CalGen....................................................................................... 91

Using Thermocouple Sensors..............................................................95

System Shielding and Grounding Issues....................................................99

Instrument Calibration................................................................................101

Cryo-con Calibration Services.............................................................. 101

Calibration Interval...............................................................................101

Remote Operation......................................................................................102

Remote Interface Configuration...........................................................102

Remote Programming Guide...................................................................... 105

General Overview................................................................................ 105

An Introduction to the SCPI Language................................................. 106

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Cryo-con Model 24C

Remote Command Tree....................................................................... 115

Remote Command Descriptions..........................................................119

Code snippet in C++............................................................................ 138

EU Declaration of Conformity..................................................................... 139

Appendix A: Installed Sensor Curves..........................................................141

Factory Installed Curves.......................................................................141

User Installed Sensor Curves...............................................................142

Sensor Curves on CD..........................................................................143

User Calibration Curve File Format......................................................143

Appendix B: Updating Instrument Firmware...............................................147

Discussion............................................................................................ 147

Updating unit firmware.........................................................................148

Appendix C: Troubleshooting Guide...........................................................151

Error Displays....................................................................................... 151

Control Loop and Heater Problems......................................................152

Temperature Measurement Errors.......................................................153

Remote I/O problems...........................................................................154

General problems................................................................................ 156

Appendix D: Tuning Control Loops.............................................................157

Introduction.......................................................................................... 157

Various methods for obtaining PID coefficients....................................157

Manual Tuning Procedures..................................................................158

Appendix E: Sensor Data...........................................................................159

Cryo-con S700 Silicon Diode................................................................159

Cryo-con S900 Silicon Diode................................................................160

Cryo-con R500 Ruthenium-Oxide Sensor............................................161

Cryo-con R400 Ruthenium-Oxide Sensor............................................162

Sensor Packages.................................................................................163

Appendix F: Configuration Scripts.............................................................. 167

Script File Structure ............................................................................. 167

Script File Example..............................................................................170

Appendix G: Sensor Data Tables................................................................173

Silicon Diode........................................................................................173

Platinum RTD....................................................................................... 175

Rhodium-Iron....................................................................................... 175

Cryogenic Linear Temperature Sensor (CLTS)....................................175

Cernox™..............................................................................................176

Ruthenium-Oxide.................................................................................178

Appendix H: Rear Panel Connections........................................................181

Sensor Connections............................................................................. 181

Control Loop #1 Connections...............................................................183

Control Loop #2 and Relay Connections.............................................183

Ethernet (LAN) Connection..................................................................184

IEEE-488.2 Connections...................................................................... 184

RS-232 Connections............................................................................184

Index........................................................................................................... 185

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Cryo-con Model 24C

Index of Figures

Figure 1: 4122-030 Rack Mount Kit............................................................9

Figure 2: 4034-032 Rack Mount Kit............................................................10

Figure 3: Model 24C Rear Panel Layout.................................................... 37

Figure 4: Model 24C Front Panel Layout...................................................41

Figure 5: Thermocouple Module.................................................................95

Figure 6: Thermocouple Switches.............................................................. 95

Figure 7: Proper Assembly of the Input Connector ....................................181

Figure 8: Diode and Resistor Sensor Connections.....................................182

Figure 9: RS-232 Null Modem Cable..........................................................184

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Cryo-con Model 24C

Index of Tables

Table 1: Model 24C Instrument Accessories...............................................14

Table 2: Cryogenic Accessories..................................................................15

Table 3: Loop #1 Output Summary.............................................................18

Table 4: Control Type Summary..................................................................19

Table 5: Supported Sensor Types...............................................................21

Table 6: Accuracy and Resolution for PTC Resistors..................................22

Table 7: Minimum and Maximum Resistance vs. Bias Voltage...................23

Table 8: Resolution for NTC Resistors........................................................24

Table 9: 10mV Constant-Voltage Accuracy Specifications..........................24

Table 10: Supported Sensor Configurations...............................................30

Table 11: PTC Resistor Sensor Configuration...........................................31

Table 12: Loop 1 Heater output ranges.......................................................34

Table 13: Loop 2 Heater output ranges.......................................................35

Table 14. AC Power Line Fuses..................................................................38

Table 15: Keypad key functions..................................................................45

Table 16: Temperature Units.......................................................................47

Table 17: Input Channel Configuration Menu..............................................52

Table 18: Control Loop Setup Menus..........................................................55

Table 19: User Configurations Menu..........................................................59

Table 20: System Configuration Menu........................................................ 60

Table 21: Over Temperature Disconnect Configuration..............................62

Table 22: Network Configuration Menu.......................................................64

Table 23: PID Table Edit Menu................................................................... 66

Table 24: Sensor Setup Menu....................................................................67

Table 25: Calibration Curve Menu...............................................................68

Table 26: Auto Tune Menu..........................................................................69

Table 27: digital output Status Indicators....................................................71

Table 28: Digital Output Modes...................................................................71

Table 29: Recommended Sensor Configuration Data.................................78

Table 30: Autotune Menu............................................................................ 83

Table 31: Autotune States...........................................................................84

Table 32: First CalGen Menu, Diode Sensor..............................................92

Table 33: CalGen Menu, 2-point Diode Sensor...........................................93

Table 34: CalGen New Curve Menu...........................................................94

Table 35: Thermocouple Polarities.............................................................97

Table 36: GPIB Host Setup Parameters.....................................................103

Table 37: BB Package Specifications.........................................................164

Table 38: Input Connector Pin-out..............................................................181

Table 39: Sensor Cable Color Codes.........................................................182

Table 40: Loop 1 Connections....................................................................183

Table 41: Loop #2 and Digital Output Connections....................................183

Table 42: RS-232 DB-9 Connector Pinout.................................................184

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Cryo-con Model 24C Introduction

Introduction

The Model 24C is a four-input, four-control loop cryogenic temperature controller
designed for general purpose laboratory and industrial use. Each input is independent
and capable of temperature measurement to <100mK with an appropriate
temperature sensor. The Model 24C supports virtually any cryogenic temperature
sensor produced by any manufacturer.

The four-output control loop circuits feature a primary 50W heater, a secondary
heater of 25W and two 10-Volt non-powered outputs. All control modes are supported
by all outputs.

The 24C front panel incorporates a large high resolution graphics TFT type Liquid
Crystal Display with an exceptionally wide viewing angle. With it's bright white LED
back-light, complete instrument status can be seen at a glance, even from across the
room.

Sensor Inputs

The Model 24C has four identical input channels, each of which implements a
ratiometric AC resistance bridge. This bridge uses separate, balanced circuits to
simultaneously measure both the voltage drop across the temperature sensor and the
current flowing through it. By measuring current with a higher accuracy than it can be
set, precision resistance measurements are obtained, even at low excitation levels.

Negative-Temperature-Coefficient (NTC) resistors are often used as low temperature
thermometers, especially at ultra-low temperature. Examples include Ruthenium­oxide, Carbon-Glass, Cernox™, Carbon-Ceramic, Germanium and several others.
Their resistance and sensitivity increase dramatically at low temperature but their
sensitivity is usually poor at warmer temperatures.

The Model 24C provides robust support for NTC resistor sensors by using constant­voltage AC excitation. In the warm region where the sensor has low resistance and
low sensitivity, constant-voltage will apply a high excitation current to improve
measurement accuracy. At low temperature where the sensor has high sensitivity and
high resistance, measurement errors are dominated by sensor self-heating.
Constant-voltage excitation reduces this error by reducing power dissipated in the
sensor as temperature decreases.

A common source of error at ultra-low temperature is sensor self-heating due to DC
offsets in the measurement electronics. The Model 24C resistance bridge measures
the actual current flowing through the sensor to actively cancel DC offsets by using a
feedback loop to offset it's excitation source.

Ultra-low temperature systems can be negatively affected by coarse steps in
excitation current. The Model 24C prevents this by using a step-less, continuously
variable excitation source.

Positive Temperature Coefficient (PTC) resistor sensors including Platinum, CLTS
and Rhodium-Iron RTDs use the resistance bridge in a constant-current, AC mode.
Platinum RTD sensors use a built-in DIN standard calibration curve that has been
extended to 14K for cryogenic use. Lower temperature use is possible with custom
calibrations.

1

Cryo-con Model 24C Introduction

Silicon diode sensors are supported over their full temperature range by using the
bridge in a DC, constant-current mode.

Thermocouple sensors are supported by using an optional thermocouple module
that plugs into any of the Model 24C's input channels. Up to four modules can be
connected to a single instrument.

For all sensor types, conversion of a sensor reading into temperature is performed by
using a Cubic Spline interpolation algorithm. In addition to providing higher accuracy
than conventional linear interpolation, the spline function eliminates discontinuities
during temperature ramps or sweeps by ensuring that the first and second derivatives
are continuous.

Control Loops

There are four independent control loop outputs:

1. Loop #1 heater output is a linear, low noise RFI filtered current source that

can provide up to 1.0 Ampere into 50 resistive loads. Three full-scale

ranges are available in decade increments down to 500mW full-scale.

2. Loop #2 is a linear heater with two output ranges of 25-Watts and 2.5-Watt

full-scale into a 50 load.

3. Loop #3 and #4 are a non-powered analog voltage output intended to control

an external booster power supply. Output is selectable at 10 or 5 Volts full

scale.

User Interface

The Model 24C’s user interface consists of a large, bright TFT type Liquid Crystal
Display and a full 21-key keypad. In this user-friendly interface, all features and
functions of the instrument can be accessed via this simple and intuitive menu driven
interface.

The Home screen projects four user configurable zones that allow the real-time
display of all input channel, control loop and instrument status information. From this
screen, accessing any of
the instrument's
configuration menus
requires only the press of
a single key. As always,
convenient names can be
assigned to input

1A:Sample Holder 2B:First Stage

251.445K 123.845K

300.000K 1-Off-Low 100.000K 2-Off-Low
C:Second Stage D:Rad Shield

15.445K 4.845K

RO-600 RuOx 10mV R500 RuOx 1.0mV

channels.

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Cryo-con Model 24C Introduction

Cryo-con's innovative instrument configuration menus show real-time status
information so the user can instantly view the results of any changes made.

On the control loop menu,
the controlling source
temperature, heater range
and power output level can
be observed while tuning a
loop.

Loop 1A:Sample Holder
Set Pt:300.000K
Pgain: 6.000
Igain: 60.00S
Dgain: 7.500/S
Pman: 5.0000%
Type: RampT
Input: ChA

A: 123.456K
Ramp 42% of Mid

Range: MID
PID Table index: 2

Htr Load: 50W
Next2

An essential feature for
debugging system software
is the Network Configuration
Menu's ability to show
remote commands as they

Network Configuration Menu
Dev: M24C1234
DHCP Ena: On
Msk:255.255.255.0

00:50:C2:6F:40:3C
IP: 192.168.0.198
GWy:192.168.0.1

are sent and received to the
instrument.

>input a:temp?;units?;name?;sys:time?
<0.5321;K;Sample Holder;14:37:25.

Sensor Curves: The Model 24C includes built-in curves that support most

industry standard temperature sensors. Additionally, eight user calibration curves
are available for custom or calibrated sensors. Each user curve may have up to 200
entries and are entered from the front panel, or transferred via any of the available
remote interfaces.

New calibration curves may be generated using the CalGen feature to fit any existing
diode, Platinum or NTC resistor calibration curve at up to three user specified
temperature points. This provides an easy and effective method for obtaining higher
accuracy temperature measurements without expensive sensor calibrations.

Data logging is performed by continuously recording to an internal 1,365 entry

circular buffer. Data is time stamped so that the actual time of an event can be
determined. Non-volatile memory is used so that data will survive a power failure.

Input Channel Statistics: The Model 24C continuously tracks temperature

history independently on each input channel and provides a statistical summary that
indicates the channel's minimum, maximum, average and standard deviation. Also
shown are the slope and the offset of the best-fit straight line of temperature history
data.

Alarms: Visual, remote and audible alarms are independently programmed to

assert, or clear based on high or low temperature condition, or a detected sensor
fault. Latched alarms are asserted on an alarm condition and will remain asserted
until cleared by the user.

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Cryo-con Model 24C Introduction

Relays: The Model 24C has two 10-Ampere dry-contact relays. These can be used

to control a refrigerator system or other external equipment.
Each relay can be asserted or cleared based on the temperature reading of a

selected input channel. High and low setpoints may be set from the front panel or a
remote interface. Furthermore, the relays can be manually asserted ON or OFF.

Remote Control

Standard Remote Interfaces include Ethernet and RS-232. IEEE-488.2(GPIB) and
USB are optional.

The Model 24C connects directly to any Ethernet Local-Area-Network (LAN) to make
measurements easily and economically. TCP/IP and UDP data port servers brings
fast Ethernet connectivity to all common data acquisition software programs including
LabView. An ASCII text based command language identical to those commonly
used with GPIB or RS-232 interfaces is implemented. This is the primary way that
user software interfaces to the instrument.

Using the Ethernet SMTP protocol, the controller will send e-mail based on selected
alarm conditions. E-mail is configured by using the web page interface.

Using the Ethernet HTTP protocol, the instrument’s embedded web server allows the
instrument to be viewed and configured from any web browser.

4

Cryo-con Model 24C Introduction

5

Cryo-con Model 24C Introduction

In order to eliminate ground-loop and noise pickup problems commonly associated
with IEEE-488 systems, the Model 24C moves the internal IEEE-488 circuitry to an
optional external module that interfaces directly to the electrically isolated and low
noise Ethernet interface. This compact module is completely transparent to the IEEE­488 system and does not require changes to customer software or LabView drivers.

Remote Command Language: The Model 24C's remote command language

is SCPI compliant according to the IEEE-488.2 specification. SCPI establishes a
common language and syntax across various types of instruments. It is easy to learn
and easy to read.

The SCPI command language is identical across all Cryo-con products so that the
user's investment in system software is always protected.

Command Scripts can be used to completely configure an instrument including

setting custom sensor calibration curves and PID tables. Further, scripts can query
and test data. They are commonly used in a manufacturing environment to set a
baseline state and test a target product. In the laboratory, scripts can be used to save
and restore configurations for various experiments.

XML (Extensible Markup Language) is used for the structure and format of script files.
XML can be generated and edited with a standard text editor. Further, it is easy to
read and understand.

Firmware updates: Instrument firmware updates may be installed by using the

Ethernet connection. Cryo-con provides firmware updates, on request, via e-mail.
They are free of charge and generally include enhancements and new features as
well as problem fixes. Send e-mail to [e-mail]

Ethernet API: An Applications Program Interface (API) package is supplied that

facilitates communication with the instrument using the TCP/IP and UDP protocols. It
is supplied as a Microsoft Windows DLL that is easily linked with C, C++ or Basic
programs.

6

Cryo-con Model 24C Preparing the controller for use

Preparing the controller for use

The following steps help you verify that the controller is ready for use.

Supplied Items

Confirm that you have received the following items with your controller. If anything is
missing, contact Cryogenic Control Systems, Inc. directly.

 Model 24C Cryogenic Temperature Controller.
 This User’s Manual.
 Cryo-con software CD.
 Input connector kit (4024-016) consisting of four screw-in DIN-6 input

connectors (PN 04-0414).

 Output connector kit (4124-018) consisting of a 10-pin detachable

terminal block (04-0007) and a dual banana plug(04-0433).

 Detachable 120VAC USA Line Cord (04-0310), or universal Euro cord.
 Certificate of Calibration.

Verify the AC Power Line Voltage Selection

The AC power line voltage is set to the proper value for your country when the
controller is shipped from the factory. Change the voltage setting if it is not correct.
The settings are: 100, 120 220, or 240 VAC. For 230 VAC operation, use the 240 VAC
setting.

On the rear panel of the instrument, the AC voltage selection is on the power entry
module. If the setting is incorrect, please refer to section Fuse Replacement and

Voltage Selection to change it.

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Cryo-con Model 24C Preparing the controller for use

Status: Self Test

Apply Power to the Controller

Connect the power cord and turn the controller on by pressing the Power key for a
minimum of 2 Seconds. The front panel will show a Power Up display with the model
number and firmware
revision.

While the Power Up display
is shown, the controller is
performing a self-test
procedure that verifies the
proper function of internal
data and program
memories, remote interfaces and input/output channels. If an error is detected during
this process, the controller will freeze operation with an error message display. In this
case, turn the unit off and refer to Appendix C: Troubleshooting Guide.

Caution: Do not remove the instrument’s cover or attempt to repair
the controller. There are no user serviceable parts, jumpers or
switches inside the unit. Further, there are no software ROM chips,
trim pots, batteries or battery-backed memories.
All firmware installation and instrument calibration functions are
performed externally via the remote interfaces.

Cryogenic Control Systems, Inc.
Model 24C SN:209999 Rev: 1.23B
IP:192.168.1.5 Static Port: 5000
MAC: 00:50:c2:6f:40:3E
Calibration: Testing NVRAM: Testing
Device Name: NewCryocon Connecting
GPIB Adrs: 012 RS232: 9600

After about fifteen seconds, the self-test will complete and the controller will begin
normal operation.

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Cryo-con Model 24C Preparing the controller for use

Installation

General

The Model 24C can be used as a bench top instrument, or mounted in an equipment
rack. In either case, it is important to ensure that adequate ventilation is provided.

Cooling airflow enters through the side holes and exhausts out the fan on the rear
panel. It is important to allow at least ½" of clearance on the left and right sides and to
ensure that the exhaust path of the fan is not blocked.

Rack Mounting

You can rack mount the controller in a standard 19-inch rack cabinet using the
optional rack mount kit. Instructions and mounting hardware are included with the kit.

4122-030 Single instrument 2U rack mount kit.

4034-032 Single instrument shelf rack mount kit.

4034-031 Dual instrument shelf rack mount kit.

Figure 1: 4122-030 Rack Mount Kit

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Cryo-con Model 24C Preparing the controller for use

Using the one- or two-instrument shelf rack mount kit, additional equipment may be
mounted on the shelf space next to the controller. Note that these rack mount kits
extends the height of the controller from 2U (3½") to 3U (5¼").
Since the controller is an industry standard size, it is possible to mount any similar
size instrument next to it in the rack.

Figure 2: 4034-032 Rack Mount Kit

10

Warning: When using the shelf type rack mount kits, do not use
screws that protrude into the bottom of instrument more than ¼".
Otherwise, they can touch internal circuitry and damage it.

Cryo-con Model 24C Preparing the controller for use

Initial Setup and Configuration

Before attempting to control temperature, the following instrument parameters should
be checked:

1. The Loop #1Heater resistance setting should match the actual heater
resistance that you are going to use. Choices are 50 and 25. A heater
resistance of less than 25 should use the 25 setting. Using the 50
setting with a heater resistance much less than 50 may cause the
instrument to overheat and disengage the control loops.

Set the heater resistance by pressing the Loop 1 key and refer to the Loop

Configuration Menu section.

2. The Loop #1 heater range should be set to a range where the maximum
output power will not damage the equipment. To set this parameter, press the
Loop 1 key and refer to the Loop Configuration Menu section.

3. The controller has an over-temperature disconnect feature that monitors a
selected input and will disconnect both control loops if the specified
temperature is exceeded. This feature should be enabled in order to protect
your equipment from being over heated. To enable, press the System key
and refer to the System Functions Menu section.

i NOTE: Factory defaults may be restored at any time by use of
the following sequence: 1) Turn AC power OFF. 2) Press and hold
the Enter key while turning power back ON. This sequence will
restore factory defaults including resetting user supplied sensor
calibration curves and saved user configurations. However, it will
NOT erase the instrument’s internal calibration data.

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Cryo-con Model 24C Preparing the controller for use

Model Identification

The model number of all Cryo-con controllers is identified on the front and rear panel
of the instrument as well as in various instrument displays.

Ordering Information

Standard Description

Model 24C

Controller with four standard multi-function sensor input channels.

Controller includes: User's Manual, Cryo-con software CD, four
input connectors, heater connector, terminal block plug, detachable
power cord and a certificate of calibration.

Specify AC Line Voltage when ordering:

-100 Configured for 90 - 100VAC with detachable USA power
cord.

-110 Configured for 110 - 120VAC with detachable USA power
cord.

-220 Configured for 220VAC with detachable universal Euro
(Shuko) line cord.

-240 Configured for 240VAC with detachable universal Euro
(Shuko) line cord.

Options Description

4039-004

4001-002

4001-001

Thermocouple Input Module. Field installable. Supports all
thermocouple types. Controller supports up to 4 modules.

IEEE-488.2 (GPIB) Option. Field installable.

USB Option. Serial Port Emulation. Field installable.

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Cryo-con Model 24C Preparing the controller for use

Technical Assistance

Troubleshooting guides and user’s manuals are available on our web page at
http://www.cryocon.com.
Technical assistance may be also be obtained by contacting Cryo-con as follows:

Cryogenic Control Systems, Inc.
PO Box 7012
Rancho Santa Fe, CA 92067-7012

Telephone: [phone]x100 FAX: [phone]
e-mail: [e-mail]

For updates to LabView™ drivers, Cryo-con utility software and product
documentation, go to our web site and select the Download area.

Current Firmware Revision Level

As of July, 2014 the firmware
revision level for the Model 24C
series is 2.52. Instrument firmware
can be updated in the field via the
LAN port. Updates are available on
the Internet.

Current Hardware Revision Level

As of July, 2014, the hardware
revision level for the Model 24C

Hardware

Revision

Relay contact
rating

Non-powered
outputs

Loop 2 output

A B, C

2.0A, 30W 10.0A, 150W

10.0V

10W or 1.0W-

Volt full-scale

Selectable 10V or 5V

full scale.

25W or 2.5W-Volt full-

scale

series is C.

Returning Equipment

If an instrument must be returned to Cryo-con for repair or recalibration, a Return
Material Authorization (RMA) number must first be obtained from the factory. This
may be done by Telephone, FAX or e-mail.

When requesting an RMA, please provide the following information:

1. Instrument model and serial number.

2. User contact information.

3. Return shipping address.

4. If the return is for service, please provide a description of the malfunction.

If possible, the original packing material should be retained for reshipment. If not
available, consult factory for packing assistance.

Cryo-con’s shipping address is:

Cryogenic Control Systems, Inc.
17279 La Brisa
Rancho Santa Fe, CA 92067-7012

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Cryo-con Model 24C Preparing the controller for use

Instrument Accessories

Cryo-con Part # Description

4034-031

4034-032 One instrument shelf rack mount kit

4034-035

04-0310

04-0317 AC Power Cord, Cont. European (Shuko)

04-0414

04-0007 Ten-pin detachable terminal block for Loop 2 and relay connections.

04-0433

4042-040 8' Sensor cable, four wire, wired to DIN-6 connector.

3124-029

Two instrument shelf rack mount kit

Shielded IEEE-488.2 Interface Bus Cable, 6'6"

AC Power Cord

Din-6 Sensor Input Connector, Amphenol T3400 001

Dual banana plug for Loop 1 connection.

Additional User’s Manual/CD

Table 1: Model 24C Instrument Accessories

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Cryo-con Model 24C Preparing the controller for use

Cryogenic Accessories

Cryo-con Part # Description

S900

S900 series Silicon diode Temperature Sensors. Temperature
range: 1.4 to 500K

Cryo-con R400 Ruthenium-Oxide temperature sensor.

R400

Temperature range: 2.0K to 273K. Optimized for use in Liquid
Helium systems including superconducting magnets.

R500

Cryo-con R500 Ultra-low temperature Ruthenium-Oxide
temperature sensor. Temperature range: <100mK to 40K.

CP-100

GP-100

XP-100

XP-1K

3039-002

3039-001

4039-011

4039-012

3039-006

CP-100 series Ceramic Wound RTD, 100

GP-100 series Glass Wound RTD, 100

XP-100 series Thin Film Platinum RTD, 100

XP-1K series Thin Film Platinum RTD, 1,000

Cartridge Heater, Silicon free, 25 / 25 Watt,
1/4" x 1 1/8". Temperature range to 1,600K

Cartridge Heater, Silicon free, 50 / 50 Watt,
1/4" x 1 1/8. Temperature range to 1,600K

Pre-cut Nichrome wire heater w/connectors, 25

Pre-cut Nichrome wire heater w/connectors, 50

Bulk Nichrome Heater Wire, 32AWG,
Polyamide insulation, 100’

Table 2: Cryogenic Accessories

15

Cryo-con Model 24C A Quick Start Guide to the User Interface.

A Quick Start Guide to the User Interface.

Pressing the Power key will toggle the controller's AC power on and off. This key
must be pressed and held for two seconds before power will toggle.

Pressing the Stop key will immediately disengage both control loops. Pressing the
Control key will engage them.

Use the ESC key to exit an erroneous entry.

Home Status Display

Pressing the Home key will return the screen to the Home Display from anywhere in
the sub-menus. The Home Display is the primary display for instrument status
information.

The Home Status display consists of four zone quadrants. Each zone has 4 lines,
containing 20 characters each, and can be individually configured to show useful
information with minimum clutter.

To configure zone displays, press the Display key.

Accessing the heater setpoint

To instantly access the setpoint for either control loop, press the Set Pt key.

Configuring a temperature sensor

Configuring an input sensor from the front panel is performed by using the Input
Channel Configuration Menu. First, press input channel key ChA , ChB , ChC , or
ChD to select the desired channel for configuration.

The first line of the Input Channel Configuration menu is used to change the sensor
units. It shows the selected input channel, the current
temperature (in real time) and the current units. An
example is shown here.

To change the sensor units, use the + and 0 keys to scroll through the available
options. When the desired units are shown, press the Enter key to make the
selection. The display will now show the current temperature with the new units.

Next, go to the sensor selection field by pressing the down arrow navigation key. This
field is used to select the actual sensor type. In the example shown below, the input
channel is currently configured for a standard Cryo-con S900 diode sensor. Use the +
and 0 keys to scroll through the available sensors including user sensors. When the
desired sensor is shown, press the Enter key to make the selection. A complete
listing of selectable sensors is given in Appendix A.

Before one of the user-supplied sensors can be
used, the sensor’s calibration curve and configuration data must be installed. This is
best done by using Cryo-con’s utility software.

This completes the process of configuring an input channel. Press the Home key to
return to the Home Status display.

+ --

+Sen: 1 Cryocon S900

17

Cryo-con Model 24C A Quick Start Guide to the User Interface.

+

Configuring the Control Loops

Before using the Loop #1 (main heater) control output, it is essential that the proper
load resistance and output range be selected. This is done using the Control Loop
Setup menu as follows:

 Press the Loop 1 key.
 In the Control Loop Configuration menu, Use the up, down, right and left

keys to scroll to the Htr Resistance field. An example is shown here:

 Use the + and 0 keys to select between a 50-

Ohm and a 25-Ohm heater and then press
the Enter key.

 Use the navigation keys to scroll to the Range

+

field and then select the desired heater range.
Be sure to select a range that does not exceed the ratings of your cryostat. A
summary of full-scale output power for the various ranges is given here:

Range

Hi

Mid

Low

Max. Output Power

25 50

25 Watts 50 Watts

2.5 Watts 5.0 Watts

0.25 Watts 0.50 Watts

Table 3: Loop #1 Output Summary

Next, the control type should be set by scrolling to the Type field and selecting the
desired loop operating mode.

+

18

Cryo-con Model 24C A Quick Start Guide to the User Interface.

A summary of control types is given here:

Type Description

Off

Control loop is disabled.

Manual control mode. Here, a constant heater output power is

Man

applied. The Pman field selects the output power as a percentage of
full-scale.

Table

PID

RampP

RampT

PID control mode where the PID coefficients are generated from a
stored, user supplied PID table.

Standard PID control.

Temperature ramp control. Uses PID control to perform a
temperature ramp.

Temperature ramp control using a PID table. Uses PID control to
perform a temperature ramp.

Table 4: Control Type Summary

Caution: The Model 24C has an automatic control-on-power-up

feature. If enabled, the controller will automatically begin controlling
temperature whenever AC power is applied. For a complete
description of this function, please see the Auto Ctl function in the

System Functions menu section.

Restoring Factory Defaults

Factory default settings may be restored with the following simple procedure:

1. Turn AC power OFF by pressing the Power key.

2. Press and hold the Enter key while turning AC power back ON. Keep the

key pressed until you see the power-up display indicating that defaults
have been restored.

i NOTE: Factory defaults may be restored at any time by use of
the following sequence: 1) Turn AC power OFF. 2) Press and hold
the Enter key while turning power back ON. This sequence will
restore factory defaults including resetting user supplied sensor
calibration curves and saved user configurations. However, it will
NOT erase the instrument’s internal calibration data.

19

Cryo-con Model 24C Specifications, Features and Functions

Specifications, Features and Functions

Specification Summary

User Interface

Display Type: 40 character by 8 line TFT LCD with LED backlight.
Number of Inputs Displayed: Four.
Keypad: Sealed Silicon Rubber.
Temperature Display: Six significant digits, autoranged.
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 types.

Sensor Connection: 4-wire differential. Screw-in type DIN-6 circular.

Connections are described in the Sensor Connections section.

Supported Sensors Include:

Type Excitation

Silicon diode

Platinum RTD

Cernox™ Constant-Voltage AC 100mK to 420K Lakeshore, all types

Ruthenium-Oxide

Carbon-Ceramic

Rhodium-Iron Constant-Current, 1mA AC 1.4 to 800K Oxford PHZ 0002

Germanium
Thermistor
Silicon
Thermistor

Thermistor

CLTS Constant-current, 100uA AC 4 to 325K Vishay CLTS-2B

Thermocouple

Constant-Current, 1mA AC 14 to 1200K

10mA DC

Constant-Voltage AC 100mK to 273K SI RO-600, SI RO-105

Constant-Voltage AC 1.0K to 300K TMi-A1

Constant-Voltage AC 100mK to 100K AdSem, Inc.

Constant-Voltage AC 1.0K to 400K AdSem, Inc.

Constant-Voltage AC 193 - 523K Measurement Specialties

None 1.4 to 1500K All thermocouple type

Temperature

Range

1.4 to 475K

Example

Cryo-con S900
SI-440, 430, 410
Lakeshore DT-670, 470

Cryo-con CP-100
Cryo-con GP-100
Cryo-con XP-100
Cryo-con XP-1K

Table 5: Supported Sensor Types

21

Cryo-con Model 24C Specifications, Features and Functions

Sensor Selection: Front Panel or remote interface. There are no internal

jumpers or switches.

Sample Rate: 15Hz per channel in all measurement modes.

Digital Resolution: 24 bits.

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.

Sensor Performance Specifications:

Diode Sensors

Configuration: Constant-Current mode, 10mA ± 0.05% DC excitation.

Note: Current source error has negligible effect on measurement accuracy.

Input voltage range: 0 to 2.00VDC.
Accuracy: ±(80mV + 0.005% * reading)
Resolution: 2.3mV
Drift: 25ppm/ºC over an ambient temperature range of 25ºC± 5ºC.

PTC Resistor Sensors

Configuration: Constant-Current AC resistance bridge mode.

Ratiometric measurement cancels any error in excitation current.

Drift: 20ppm/ºC over an ambient temperature range of 25ºC± 5ºC.
AC Excitation Frequency: 7.5Hz bipolar square wave.

22

Range

PTC100

1mA

PTC1K

100mA

Max/Min

Resistance

500W

0.01W

7.5KW

0.1W

Table 6: Accuracy and Resolution for PTC Resistors

Excitation

Current

1.0mA

100mA 1.0mW

Resolution Accuracy

0.1mW

± (0.004 + 0.01%)Ω

± (0.05 + 0.02%)Ω

Note: The Model 24C is calibrated with AC excitation. User
selection of DC excitation will introduce offset errors in temperature
measurement.

Cryo-con Model 24C Specifications, Features and Functions

Thermocouple Sensors

Thermocouple devices are supported by using an optional external module.

Measurement Drift: 25ppm/ºC Input Range: ±70mV
Accuracy: ±1.0µ V ± 0.05%. Resolution: 0.0003%

Installed Types: K, E, T and Chromel-AuFe (0.07%).
Input Connector: Isothermal, Screw-type terminals.

NTC Resistor Sensors

Type: Constant-Voltage AC resistance bridge with excitations

of 10mV, 3.0mV, 1.0mV and 300µV RMS. Fixed or auto-ranged.

Excitation Current: 2.5mA to 10nA.

Four ranges of 2.5mA, 250uA and 25uA full-scale.

Excitation Frequency: 7.5Hz bipolar square wave.
Drift: >10W and <10KW: 15ppm/ºC

<10W or >10KW: 25ppm/ºC

over an ambient temperature range of 25ºC± 5ºC.

DC Offset Current: <8nA by active cancellation.
Resistance Range: 0.5W to 1.0MW.

Resistance 10mV 3.0mV 1.0mV 300µV

Maximum

Minimum

Table 7: Minimum and Maximum Resistance vs. Bias Voltage

1.0MW 100KW 100KW 33KW

1W 0.5W 0.5W 0.16W

23

Cryo-con Model 24C Specifications, Features and Functions

Resolution: Shown below are typical RMS resistance noise values measured
at 50% of full-scale on a room-temperature resistor with a 3-Second analog
time-constant.

Range 10mV 3.0mV 1.0mV

40W

400W

4KW

40KW

Table 8: Resolution for NTC Resistors

1.0mA
255µW

100μA

2.6mW

10μA

26mW

1.0μA

250mW

1.0mA
255µW

100μA

2.6mW

10μA

26mW

1.0μA

250mW

100μA

2.6mW

10μA

26mW

1.0μA

260mW

1.0μA

2.5W

Accuracy: Accuracy for the 10mV bias setting is specified in ranges
according to the following table. The formulas apply from the maximum to the
minimum resistance shown below.

Resistance

Range

1Ω

4Ω

40Ω

400Ω

4KΩ

100KΩ

Excitation

Current

Range

1.0mA 1 - 4Ω ±0.02Ω ± 0.05% * Rdg

1.0mA 4 - 40Ω ±0.02Ω ± 0.05% * Rdg

100µA 40 - 400Ω ±0.2Ω ± 0.05% * Rdg

10µA 400 - 4KΩ ±2.0Ω ± 0.05% * Rdg

10µA 4K - 40KΩ ±20Ω ± 0.05% * Rdg

10µA 40K - 100KΩ ±50Ω ± 0.1% * Rdg

Min/Max

Resistance

Accuracy at 25C

Table 9: 10mV Constant-Voltage Accuracy Specifications

While it is possible to measure resistance above100KΩ, accuracy is not
guaranteed.

The 1.0mV and lower bias settings are provided for use in very low
temperature applications (<~1K) where errors are often dominated by sensor
self heating rather than the accuracy of resistance measurement. In the

1.0mV range, the Model 24C will have an accuracy of ± 0.5% over the
resistance range of 40 to 10.0KΩ.

24