Omega Engineering CYTX231 Series User manual

Omega Model CYTX231 User’s Manual
Table of Contents i
TABLE OF CONTENTS
Chapter/Paragraph Title Page
1 INTRODUCTION.......................................................................... 1-1
1.0 General .......................................................................... 1-1
1.1 Model CYTX231 System Description............................. 1-1
1.2 Single Enclosure Case Description................................ 1-6
1.3 Multiple Unit Enclosure Case Description ...................... 1-7
2 INSTALLATION........................................................................... 2-1
2.0 General .......................................................................... 2-1
2.1 Inspection and Unpacking.............................................. 2-1
2.2 Repackaging For Shipment ........................................... 2-1
2.3 Sensor Installation Recommendations........................... 2-2
2.3.1 Two-Lead vs. Four-Lead Measurements.................... 2-2
2.3.1.1 Two-Lead Measurements ....................................... 2-2
2.3.1.2 Four-Lead Measurements ...................................... 2-3
2.3.2 Connecting Leads To The Sensor.............................. 2-3
2.3.3 Sensor Mounting ........................................................ 2-3
2.3.4 Measurement Errors Due To AC Noise...................... 2-5
2.4 Sensor Curve Definition ................................................. 2-6
2.5 Power Connections........................................................ 2-7
3 OPERATION................................................................................ 3-1
3.0 General .......................................................................... 3-1
3.1 PCB DIP Switch Settings ............................................... 3-1
3.2 Output to Temperature Conversion ............................... 3-2
4 SERVICE ..................................................................................... 4-1
4.0 General .......................................................................... 4-1
4.1 General Troubleshooting ............................................... 4-1
4.1.1 No Output (On-Board LED Off) .................................. 4-1
4.1.2 Output Stops Before Reaching Upper Limit ............... 4-1
4.1.3 Output Is Incorrect Value (Small Error) ...................... 4-1
4.1.4 Output Is Incorrect Value (Large Error) ...................... 4-2
4.2 Model CYTX231 Connector Definitions ......................... 4-2
4.3 Calibration...................................................................... 4-3
4.3.1 Test Equipment Required........................................... 4-3
4.3.2 Reference Calibration................................................. 4-4
4.3.3 Output Calibration ...................................................... 4-5

Omega Model CYTX231 User’s Manual
ii Table of Contents
TABLE OF CONTENTS (Continued)
Chapter/Paragraph Title Page
5 OPTIONS AND ACCESSORIES ................................................. 5-1
5.0 General .......................................................................... 5-1
5.1 Enclosures .....................................................................5-1
5.2 Options ..........................................................................5-1
5.3 Accessories....................................................................5-2
5.4 Wires.............................................................................. 5-2
5.5 Sensors.......................................................................... 5-3
5.6 Special Equipment ......................................................... 5-3
APPENDIX A – MODEL CYTX231 CURVE TABLES ....................... A-1
APPENDIX B – GLOSSARY OF TERMINOLOGY............................ B-1
LIST OF ILLUSTRATIONS
Figure No. Title Page
1-1 Typical Model CYTX231 Front Panel .................................... 1-2
1-2 Single Enclosure Case Physical Dimensions........................ 1-6
1-3 Multiple Unit Case Physical Dimensions ............................... 1-8
2-1 Typical Wall Plug-In Power Supply ....................................... 2-8
3-1 Model CYTX231 DIP Switch (S1).......................................... 3-1
4-1 Front Panel Connectors J2 & J3 Details ............................... 4-2
4-2 VMEbus Connector J1 Details .............................................. 4-3
4-3 Model CYTX231 PCB Layout................................................ 4-4
LIST OF TABLES
Table No. Title Page
1-1 Model CYTX231 Input Specifications .................................... 1-3
1-2 Model CYTX231P Input Specifications ................................. 1-4
1-3 Model CYTX231SD & 231P Output Specifications ............... 1-5
1-4 Model VMEbus Rackmount Case Specs ..............................1-7
2-1 Effect of Current Variation on Diode Temperature ................ 2-5
2-2 Typical dV/dI Values for Selected Temps ............................. 2-5
3-1 Conversion Parameters for Temperature in K....................... 3-2
A-1 Omega Standard Diode Curves ............................................A-1
A-2 Series Platinum Resistance Curve........................................A-2

Omega Model CYTX231 User’s Manual
Introduction 1-1
CHAPTER 1
INTRODUCTION
1.0 GENERAL
A general reference to the Model CYTX231SD
means both the Model CYTX231SD and CTYX
231P. Specific references are made where
appropriate. This chapter covers a general
description with specifications in Paragraph 1.1,
single enclosure case description in Paragraph
1.2, and multiple unit enclosure case description
in Paragraph 1.3.
We welcome comments on this manual. Although
we try to keep it error-free, some may occur. To
report an error, describe it briefly and include the
appropriate paragraph, figure, table, and page
number. This manual is subject to change without
notice.
1.1 MODELL CYTX231 GENERAL
DESCRIPTION
The Model CYTX231 Temperature Transmitter is
available as a stand-alone unit or with two
enclosures: a Model CYTX231SD-115 single
space enclosure, or a Model CYTX SD-115
rackmount case that holds up to 12 units.
The Model CYTX-Enclosure-12 Temperature
Transmitter sends temperature data from its
position near a sensor to a data acquisition
channel or strip chart recorder. It operates with
Silicon diode sensor. The SD Series Silicon diode
sensors are accurate over a wide cryogenic
temperature range and are interchangeable for
some applications. Excited with a 10 µA current source from the Model
CYTX231SD, the sensor produces a voltage that depends on temperature.
A microcontroller reads the voltage through an A/D converter and translates
it into temperature. The standard temperature curve relates voltage to
temperature.
The Model CYTX231P uses a Series PT-100 Platinum Thermometer. The
Model CYTX231P excites the sensor with a 500 µA current to produce a
measurable signal. The standard platinum curve (DIN 437600) is used for
temperature conversion.
Figure 1-1. Typical
Model CYTX231
Front Panel

Omega Model CYTX231 User’s Manual
1-2 Introduction
Once the Model CYTX231 obtains temperature data, it transmits it as a
current from 4 to 20 mA. The current output changes linearly with
sensor temperature. Output scale depends on the selected temperature
range. Several switch selected ranges are available. For highest
accuracy and sensitivity, set the output for a narrow temperature band.
An optional 0 to 20 mA output is also available to convert output to a
voltage reading scaled from zero. A 500 Ω±0.02% precision resistor is
provided for this purpose. This resistor produces the maximum full-scale
output of 10 V.
A single +5 VDC supply powers Model CYTX231 circuitry. The outputs
are isolated so several 231s can operate from the same supply without
interference. The +5 VDC can also be supplied from the pins on the
VME bus connector.
Mechanical mounting is easy because the CYTX231 is built on a
standard size VME card. It fits directly into a single height (3U) VME
card holder. The transmitter does not use the electrical bus format, only
its physical shape and power supply.

Omega Model CYTX231 User’s Manual
Introduction 1-3
Table 1-1. Model CYTX231 Input Specifications
Thermometry:
Number of Inputs: One input
Measurement Type: Four-lead differential measurement
Sensor Type: Silicon diode
Sensor Temp. Coefficient: Negative
Sensor Units: Volt (V)
Input Range: 0 to 5 volts
Sensor Excitation: 10 µA ±0.1% DC current
Example Sensor: CY7-SD7
Temperature Range: 1.4 K – 325 K
Standard Curve: Curve 10
Typical Sensor Sensitivity: –30 mV/K at 4.2 K
–1.9 mV/K at 77.35 K
–2.4 mV/K at 300 K
Measurement Resolution:
Sensor Units: 76.3 µV
Temp. Equivalence: 2.5 mK at 4.2 K
40 mK at 77.35 K
32 mK at 300 K
Measurement Accuracy:
Sensor Units: ±75 µV ±0.01% of reading
Temp. Accuracy *: ±0.07 K at 4.2 K
±0.16 K at 77.35 K
±0.12 K at 300 K
Measurement Temperature Coefficient:
Sensor Units: 0.0006% of voltage reading per °C
Temp. Equivalence: 3 mK/°C at 4.2 K
3 mK/°C at 77.35 K
1.2 mK/°C at 300 K

Omega Model CYTX231 User’s Manual
1-4 Introduction
Table 1-2. Model CYTX231P Input Specifications
Thermometry:
Number of Inputs: One input
Measurement Type: Four-lead differential measurement
Sensor Type: Platinum
Sensor Temp. Coefficient: Positive
Sensor Units: Ohm (Ω)
Input Range: 0 – 312 Ω
Sensor Excitation: 500 µA ±0.02% DC current
Example Sensor: PT-103
Temperature Range: 14 K – 873 K with PT-103
Standard Curve: DIN 43760
Typical Sensor Sensitivity: 0.19 Ω/K @ 30 K
0.42 Ω/K @ 77.35 K
0.39 Ω/K @ 300 K
0.34 Ω/K typical up to 800 K
Measurement Resolution:
Sensor Units: 4.8 mΩ
Temp. Equivalence: 22 mK at 30 K
11 mK at 77.35 K
13 mK at 300 K
14 mK typical up to 800 K
Measurement Accuracy:
Sensor Units: Ohms (Ω)
Temp. Accuracy: ±0.2 K at 30 K
±0.15 K at 77.35 K
±0.3 K at 300 K
±0.7 K typical up to 800 K
Measurement Temperature Coefficient:
Sensor Units: 0.002% of voltage reading per °C
Temp. Equivalence: 0.4 mK/°C at 30 K
1 mK/°C at 77.35 K
6 mK/°C at 300 K
18 mK/°C at 800 K
Magnetic Field Use: Up to 19 teslas for T > 30 K.
Update Rate: 5 readings per second.
Precision Curve Storage: 1 curve, loaded in PROM at factory.

Omega Model CYTX231 User’s Manual
Introduction 1-5
Table 1-3. Model CYTX231 and 231P Output Specifications
Output:
Number of Outputs: One
Output Type: Current source, isolated from power source
Output Range: 4-20 mA or 0-20 mA (for 0-10 V with provided
500 Ω, 0.02%, 25 ppm resistor)
Output Compliance: 10 V (500 Ωmax load)
Output Temp. Ranges: 0–20 K, 0–100 K, 0–200 K, 0–325 K,
0–475 K, and 0-1000 K
4-20 mA Output:
Output Resolution:
Current: 1.22 µA (0.006% of full scale)
Temp. Equivalence: 0–20 K = 1.5 mK 0–325 K = 24.8 mK
0–100 K = 7.6 mK 0–475 K = 36.2 mK
0–200 K = 15.3 mK 0–1000 K = 76.3 mK
Output Accuracy:
Current: 2 µA (±0.01% of full scale)
Temp. Equivalence: 0–20 K = 2.5 mK 0–325 K = 41 mK
0–100 K = 12.5 mK 0–475 K = 59 mK
0–200 K = 25 mK 0–1000 K = 125 mK
Output temperature coefficient
Current: ±0.0055% of output current per °C
Temp. Equivalence: 0–20 K = 1 mK/°C 0–325 K = 18 mK/°C
0–100 K = 6 mK/°C 0–475 K = 26 mK/°C
0–200 K = 12 mK/°C 0–1000 K = 55 mK/°C
0-20 mA Output (0-10 V w/500 Ω, 0.02% Load Resistor):
Output Resolution:
Voltage: 0.6 mV
Temp. Equivalence: 0–20 K = 1.2 mK 0–325 K = 19.8 mK
0–100 K = 6.1 mK 0–475 K = 29 mK
0–200 K = 12.2 mK 0–1000 K = 61 mK
Output Accuracy:
Voltage: 3 mV (0.03% of full scale)
Temp. Equivalence: 0–20 K = 6 mK 0–325 K = 98 mK
0–100 K = 30 mK 0–475 K = 143 mK
0–200 K = 60 mK 0–1000 K = 300 mK
Output temperature coefficient
Current: ±0.008% of output current per °C
Temp. Equivalence: 0–20 K = 2 mK/°C 0–325 K = 26 mK/°C
0–100 K = 8 mK/°C 0–475 K = 38 mK/°C
0–200 K = 16 mK/°C 0–1000 K = 80 mK/°C

Omega Model CYTX231 User’s Manual
1-6 Introduction
Table 1-3. Model CYTX231 and 231P Output Specs (Continued)
General:
Ambient Temp. Range: 15 °C to 35 °C
Power Requirement: +5 (±0.25) VDC, 500 mA
Size: 100 mm high × 160 mm deep × 30.5 mm wide
Mounting: VME end panel and back plane. Transmitter does not
use electrical bus format, only its physical shape and power supply.
Note: Electronic temperature accuracy in a given temperature
range is the sum of temperature accuracies of input and output.
Sensor calibration errors are not included.
1.2 SINGLE ENCLOSURE CASE DESCRIPTION
Holds one Model CYTX231. Typical dimensions appear below.
8.75 inches (22.23 cm)
5.5625 inches (14.13 cm)
1.5 inches
(3.81 cm)
0.1875 inches
(0.48 cm)
Front
TOP VIEW
F ONT VIEW
CYTX231
Temperature
Transmitter
OMEGA
Figure 1-2. Typical Single Enclosure Case Physical Dimensions

Omega Model CYTX231 User’s Manual
Introduction 1-7
1.3 MULTIPLE UNIT ENCLOSURE CASE DESCRIPTION
The Model CYTX-Enclosure-12 VMEbus Rackmount Case holds up to
twelve Model CYTX231 units. A +5 VDC power supply with universal input is
provided with the case. Specifications and typical dimensions of the case are
shown below. Refer to Paragraph 2.5 for further information on the built-in
power supply.
CAUTION: The Model CYTX-Enclosure-12 bus is designed only to
power multiple Model CYTX231s. Do not use with standard VME cards.
Table 1-4. Enclosure-12 VMEbus Rackmount Case Specifications
No. of Card Slots: 12
Size: 45 ×17.8 ×26 cm (17.7 ×7×10.3 inches)
Weight: 5.5 kilograms (12 pounds)
Output Voltage: +5 VDC, 100 mV Peak-to-Peak Ripple
Output Current: 6 A (Max)
Input Power: Universal 85 –265 VAC, 47 –440 Hz., 60 Watts
Ambient Temp. Range: 15 –35 °C (59 –95 °F)

Omega Model CYTX231 User’s Manual
1-8 Introduction
17.625 inches (44.8 cm)
FRONT VIEW
10.25 inches (26 cm)
7.0 inches
(17.8 cm)
SIDE
VIEW
TO VIEW
Figure 1-3. Typical Multiple Unit Case Physical Dimensions

Omega Model CYTX231 User’s Manual
Installation 2-1
CHAPTER 2
INSTALLATION
2.0 GENERAL
This chapter covers inspection and unpacking in Paragraph 2.1, repackaging
for shipment in Paragraph 2.2, sensor installation recommendations in
Paragraph 2.3, sensor curve definitions in Paragraph 2.4, and power
connections in Paragraph 2.5.
2.1 INSPECTION AND UNPACKING
Inspect shipping containers for external damage. Make all claims for
damage (apparent or concealed) or partial loss of shipment in writing to
Omega within five (5) days from receipt of goods. If damage or loss is
apparent, please notify the shipping agent immediately.
Open the shipping containers. Use the packing list included with the system to
verify receipt of the instrument, sensor, accessories, and manual. Inspect for
damage. Inventory all components supplied before discarding any shipping
materials. If there is freight damage to the instrument, file proper claims
promptly with the carrier and insurance company and notify Omega. Notify
Omega immediately of any missing parts. Omega cannot be responsible for
any missing parts unless notified within 60 days of shipment. See the standard
Omega Warranty on the A Page (immediately behind the title page).
2.2 REPACKAGING FOR SHIPMENT
To return the Model CYTX231 or accessories for repair or replacement,
obtain a Return Goods Authorization (RGA) number from Technical Service
in the United States, or from the authorized sales/service representative
from which the product was purchased. Instruments may not be accepted
without a RGA number. When returning an instrument for service, Omega
must have the following information before attempting any repair.
1. Instrument model and serial number.
2. User name, company, address, and phone number.
3. Malfunction symptoms.
4. Description of system.
5. Returned Goods Authorization (RGA) number.
Repack the system in its original container (if available). Affix shipping labels
and FRAGILE warnings. Write RGA number on the outside of the container
or on the packing slip. If not available, consult Omega for shipping and
packing instructions.

Omega Model CYTX231 User’s Manual
2-2 Installation
2.3 SENSOR INSTALLATION RECOMMENDATIONS
Refer to the Omega Product Catalog for installation details and sensor
specifications. Call Omega for copies of application notes or sensor
installation questions. Below are general recommendations on sensor
installation:
1. Do not ground the sensor.
2. Shield leads and connect shield wire to SHIELD on screw terminal
connector only. Do not connect shield at other end of cable.
3. Keep leads as short as possible.
4. Use twisted-pair wire. Use Omega CYW4 wire (or equivalent) for
two-wire, or four-wire applications.
5. Thermally anchor lead wires.
2.3.1 Two-Lead versus Four-Lead Measurements
In two-lead measurement, the leads that measure sensor voltage also carry
the current. The voltage measured at the instrument is the sum of the
temperature sensor voltage and the IR voltage drop within the two current
leads. Since heat flow down the leads can be critical in a cryogenic
environment, wire of small diameter and significant resistance per foot is
preferred to minimize this heat flow. Consequently, a voltage drop within the
leads may exist.
Four-lead measurement confines current to one pair of leads and measures
sensor voltage with the other lead pair carrying no current.
2.3.1.1 Two-Lead Measurement
Sometimes system constraints dictate
two-lead measurement. Connect the
positive terminals (V+ and I+) together
and the negative terminals (V– and I–)
together at the instrument, then run
two leads to the sensor.
Expect some loss in accuracy; the voltage measured at the voltmeter equals
the sum of the sensor voltage and the voltage drop across the connecting
leads. The exact measurement error depends on sensor sensitivity and
variations resulting from changing temperature. For example, a 10 Ωlead
resistance results in a 0.1 mV voltage error. The resultant temperature error
at liquid helium temperature is only 3 mK, but, because of the diode’s lower
sensitivity (dV/dT) at higher temperatures, it becomes 10 mK at liquid
nitrogen temperature.
I+
V+
I–
V–
Two-Lead
Measurements

Omega Model CYTX231 User’s Manual
Installation 2-3
2.3.1.2 Four-Lead Measurement
All sensors, both two-lead and four-lead
devices, can be measured in a four-lead
configuration to eliminate the effects of lead
resistance. The exact point at which the
connecting leads solder to the two-lead
sensor normally results in a negligible
temperature uncertainty.
Always use four-lead measurement configuration when a Series Platinum
Sensor is attached to the Model CYTX231P.
2.3.2 Connecting Leads To The Sensor
Excessive heat flow through connecting leads to any temperature sensor
may differ the temperature between the active sensing element and the
sample to which the sensor mounts. This reflects as a real temperature
offset between what is measured and the true sample temperature.
Eliminate such temperature errors with proper selection and installation of
connecting leads.
To minimize heat flow through the leads, select leads of small diameter and
low thermal conductivity. Phosphor-bronze or Manganin wire is commonly
used in sizes 32 or 36 AWG. These wires have a fairly low thermal
conductivity, yet electrical resistance is not large enough to create
measurement problems.
Thermally anchor lead wires at several temperatures between room
temperature and cryogenic temperatures to guarantee no heat conduction
through the leads to the sensor.
2.3.3 Sensor Mounting
Before installing a diode sensor, identify
which lead is the anode and which is the
cathode. When viewed with the base
down and the leads towards the
observer, the anode is on the right and
the cathode is on the left. The Omega
silicon diode sensor lead configuration is
shown to the right. For other sensors,
read accompanying literature or consult the manufacturer to positively
identify sensor leads. Lead identification should remain clear even after
sensor installation. Record the sensor serial number and location.
I+
V+
I–
V–
Four-Lead
Diode
CY7-SD
Diode Sensor Leads
Anode
Cathode

Omega Model CYTX231 User’s Manual
2-4 Installation
Sensor Mounting (Continued)
On the CY7-SD7, the base is the largest flat surface. It is sapphire with gold
metalization over a nickel buffer layer. The base is electrically isolated from
the sensing element and leads; make all thermal contact to the sensor
through the base. A thin braze joint around the sides of the SD package
electrically connect to the sensing element. Avoid contact to the sides with
any electrically conductive material.
When installing the sensor, make sure there are no electrical shorts or
current leakage paths between the leads or between the leads and ground.
If IMI-7031 varnish or epoxy is used, it may soften varnish-type lead
insulations so that high resistance shunts appear between wires if sufficient
time for curing is not allowed.
Slide Teflon®spaghetti tubing over bare leads when the possibility of
shorting exists. Avoid putting stress on the device leads and allow for
thermal contractions that occur during cooling which could fracture a solder
joint or lead if installed under tension at room temperature.
For temporary mounting in cold temperature applications, apply a thin layer
of Apiezon®N Grease between the sensor and sample to enhance thermal
contact under slight pressure. The preferred method for mounting the
CY7SD7sensor is the Omega CO Adapter.
CAUTION: Omega will not warranty replace any device damaged by
user-designed clamps or solder mounting.
For semi-permanent mountings, use Stycast epoxy instead of Apiezon®N
Grease. NOTE: Do not apply Stycast epoxy over the CY7-SD7 package —
sensor stress may shift the readings. In all cases, periodically inspect the
sensor mounting to verify good thermal contact to the mounting surface is
maintained.
For the Model CYTX231SD, Series CYTX231P Platinum Sensors follow the
same basic procedures for diode type sensors. However, Platinum sensors
have no lead polarity, and some of the materials used at cold temperatures
will not tolerate the high-temperature range of the Platinum sensor.

Omega Model CYTX231 User’s Manual
Installation 2-5
2.3.4 Measurement Errors Due To AC Noise
Poorly shielded leads or improperly grounded measurement systems can
introduce AC noise into the sensor leads. In diode sensors, the AC noise
shifts the DC voltage measurement due to the diode non-linear
current/voltage characteristics. When this occurs, measured DC voltage is
too low and the corresponding temperature reading is high. The
measurement error can approach several tenths of a kelvin. To determine if
this problem exists, perform either of the following procedures.
1. Place a capacitor across the diode to shunt induced AC currents.
Capacitor size depends on the noise frequency. If noise is related to
power line frequency, use a 10 microfarad capacitor. If AC-coupled digital
noise is suspected (digital circuits or interfaces), use a 0.1 to 1
microfarad capacitor. In either case, if measured DC voltage increases,
there is induced noise in the measurement system.
2. Measure AC voltage across the diode with an AC voltmeter or
oscilloscope. Most voltmeters do not have the frequency response to
measure noise associated with digital circuits or interfaces (which
operate in the MHz range). For a thorough discussion of this potential
problem, and the magnitude of error which may result, request the
paper “Measurement System-Induced Errors In Diode Thermometry,”
J.K. Krause and B.C. Dodrill, Rev. Sci. Instr. 57 (4), 661, April, 1986.
To greatly reduce potential AC noise, connect twisted leads (pairs) between
the measurement instruments and the diode sensors. Use 32 or 36 AWG
Cryogenic Wire, which features phosphor bronze wire twisted at 3.15 twists
per centimeter (8 twists per inch). See the Omega Product Catalog or
contact Omega for further information.

Omega Model CYTX231 User’s Manual
2-6 Installation
2.4 SENSOR CURVE DEFINITION
Model CYTX231 sensor curves include Curve 10 and Platinum Curve
(DIN 43760). After selecting the proper curve, refer to Paragraph 3.1 to set
the Model CYTX231 DIP switch.
Curve 10: Omega CY7-SD7 Series silicon diodes follow the same standard
temperature response Curve 10, which makes them interchangeable.
Omega programs Curve 10 into its Temperature Controllers, Digital
Thermometers, and Temperature Transmitters.
CY7-SD7 Series silicon diode sensors come in five bands of tracking
accuracy, allowing selection based on both performance and expense.
Forward Voltage  Vf (volts)
1.
1.6
1.4
1.2
1.0
0.
0.6
0.4
0.2
020 60 200 300
Temperature, K (kelvin)
Standard Curve 10
100 20 3040 5060
Average
Slope
26 mV/K
Average
Slope
2.3 mV/K
Platinum Curve: Users of the Model CYTX231P have the option of the
standard platinum curve or CalCurve. The standard platinum curve detailed
in Appendix A conforms to DIN 43760:1980; IEC 751:1983; and 1904:1984.
CalCurve: CalCurve is the easiest way to combine the additional
performance of a Omega calibrated sensor with the Model CYTX231. The
CalCurve is a read-only memory chip (PROM) with specific sensor
calibration stored on it. The CalCurve improves combined sensor/instrument
accuracy to within ±0.25K or better over the sensor’s calibrated temperature
range.

Omega Model CYTX231 User’s Manual
Installation 2-7
2.5 POWER CONNECTIONS
The Model CYTX231 is powered by the +5 VDC supply in the VME rack or
an external power supply. The voltage must be regulated to within ±0.25
VDC. Each Model CYTX231 draws up to 500 mA from the supply.
The external power supply connector must be S-760 or S-765 Switchcraft
(or equivalent) plug (0.218 inch O.D., accepts 0.08 inch diameter pin) with
the +5 VDC on the sleeve and return on the center pin.
A wall plug-in power supply Model, +5V DC, is used with the Model
CYTX231. Power Supply input is based on local power requirements as
follows:
MODEL INPUT POWER
2007-10
2007-12
2007-22
2007-24
100 V 50/60 Hz power source, Japan
120 V 60 Hz power source, North America
220 V 50 Hz power source, Continental Europe
240 V 50 Hz power source, Great Britain
CAUTION: Never ground both the sensor and the 4–20 mA output. Ground
the sensor, or the output, but not both.
The Model CYTX-Enclosure-12 VMEbus rackmount case has a built-in
power supply for up to twelve Model CYTX231s. The built-in power supply
has a universal input: 85 to 265 VAC, 47 to 440 Hz, 60 watts.

Omega Model CYTX231 User’s Manual
2-8 Installation
6-foot Cord
2.25 in (5.72 cm) wide 2.0 in (5.1 cm) deep
AC-DC
REGULATED
POWER SUPPLY
INPUT AC 120V 60Hz 12W
OUTPUT DC 5V 600mA
CAUTIONCAUTION
Indoor Use OnlyIndoor Use Only
3.125 in (7.94 cm) high
Figure 2-1. Typical Wall Plug-In Power Supply