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