Omega Engineering CYTX231 Series User Manual

Cryogenic temperature transmitters

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Summary of Contents for Omega Engineering CYTX231 Series

  • Page 3: Table Of Contents

    Omega Model CYTX231 User’s Manual TABLE OF CONTENTS Chapter/Paragraph Title Page INTRODUCTION................1-1 General ................1-1 Model CYTX231 System Description......1-1 Single Enclosure Case Description........ 1-6 Multiple Unit Enclosure Case Description ...... 1-7 INSTALLATION................2-1 General ................2-1 Inspection and Unpacking..........2-1 Repackaging For Shipment ...........
  • Page 4 Omega Model CYTX231 User’s Manual TABLE OF CONTENTS (Continued) Chapter/Paragraph Title Page OPTIONS AND ACCESSORIES ..........5-1 General ................5-1 Enclosures ..............5-1 Options ................5-1 Accessories..............5-2 Wires................5-2 Sensors................5-3 Special Equipment ............5-3 APPENDIX A – MODEL CYTX231 CURVE TABLES ....... A-1 APPENDIX B –...
  • Page 5: Introduction

    Omega Model CYTX231 User’s Manual CHAPTER 1 INTRODUCTION 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.
  • Page 6 Omega Model CYTX231 User’s Manual 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.
  • Page 7 Omega Model CYTX231 User’s Manual 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 –...
  • Page 8 Omega Model CYTX231 User’s Manual 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 –...
  • Page 9 Omega Model CYTX231 User’s Manual 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 Ω...
  • Page 10: Single Enclosure Case Description

    Omega Model CYTX231 User’s Manual 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.
  • Page 11: Multiple Unit Enclosure Case Description

    Omega Model CYTX231 User’s Manual 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.
  • Page 12 Omega Model CYTX231 User’s Manual Figure 1-3. Typical Multiple Unit Case Physical Dimensions Introduction...
  • Page 13: Installation

    Omega Model CYTX231 User’s Manual CHAPTER 2 INSTALLATION 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. INSPECTION AND UNPACKING Inspect shipping containers for external damage.
  • Page 14: Sensor Installation Recommendations

    Omega Model CYTX231 User’s Manual 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.
  • Page 15: Four-Lead Measurements

    Omega Model CYTX231 User’s Manual 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 Four-Lead resistance. The exact point at which the Diode connecting leads solder to the two-lead V–...
  • Page 16 Omega Model CYTX231 User’s Manual 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.
  • Page 17: Measurement Errors Due To Ac Noise

    Omega Model CYTX231 User’s Manual 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.
  • Page 18: Sensor Curve Definition

    Omega Model CYTX231 User’s Manual 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.
  • Page 19: Power Connections

    Omega Model CYTX231 User’s Manual 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.
  • Page 20: Typical Wall Plug-In Power Supply

    Omega Model CYTX231 User’s Manual 2.0 in (5.1 cm) deep 2.25 in (5.72 cm) wide AC-DC REGULATED POWER SUPPLY INPUT AC 120V 60Hz 12W OUTPUT DC 5V 600mA CAUTION CAUTION Indoor Use Only Indoor Use Only 6-foot Cord Figure 2-1. Typical Wall Plug-In Power Supply Installation...
  • Page 21: Operation

    Omega Model CYTX231 User’s Manual CHAPTER 3 OPERATION GENERAL This chapter covers printed circuit board (PCB) DIP switch settings in Paragraph 3.1 and output current and voltage to temperature conversion in Paragraph 3.2. PCB DIP SWITCH SETTINGS Before placing the unit into service, the Model DIP switch (S1) must be properly configured.
  • Page 22: Output To Temperature Conversion

    Omega Model CYTX231 User’s Manual PCB DIP Switch Settings (Continued) Current/Voltage (I/V) OUT is for selection of proper output type. Open is for 4–20 mA and closed is for 0–20 mA. The 4–20 mA is an industry standard, while the 0–20 mA is provided to translate output into voltage scaled up to 10 V.
  • Page 23: Service

    Omega Model CYTX231 User’s Manual CHAPTER 4 SERVICE GENERAL This chapter cover general troubleshooting in Paragraphs 4.1, Model CYTX231 connectors in Paragraph 4-2, and calibration in Paragraph 4.3. GENERAL TROUBLESHOOTING 4.1.1 No Output (On-Board LED Off) Check that external power supply output is +5 VDC. If not, replace supply. If using the front panel input jack (J2), make certain center post of connector coming from power supply is NEGATIVE.
  • Page 24: Output Is Incorrect Value (Large Error)

    Omega Model CYTX231 User’s Manual 4.1.4 Output Is Incorrect Value (Large Error) Can be caused by incorrect sensor wiring. To test wiring, place voltmeter between SENS V+ and SENS V– connection. With sensor connected, power up the Model CYTX231. With the sensor at room temperature, the voltmeter should read about 0.5 VDC for a diode sensor, or about 55 mV for a platinum sensor.
  • Page 25: Calibration

    Omega Model CYTX231 User’s Manual PIN NO. ROW A ROW B ROW C Not Used Not Used Entire Row Not Used Not Present Not Used Not Used 12-14 Not Used Not Used Not Used Not Used Not Used Not Used Not Used Not Used Not Used...
  • Page 26: Reference Calibration

    Omega Model CYTX231 User’s Manual 4.3.2 Reference Calibration Perform this reference calibration before output calibration. Connect DVM negative lead to Model CYTX231 reference ground (REF GND) on TP2, and positive lead to VREF on TP3. Adjust trimpot R33, VREF TRIM, until DVM reads 2.5000 V ±0.0001 V. Figure 4-3.
  • Page 27: Output Calibration

    Omega Model CYTX231 User’s Manual 4.3.3 Output Calibration Connect 500 Ω, 0.02% resistor to Model CYTX231 pins OUT+ and OUT–. Use jumper wires 1 and 2 to short V+ to I+ and V– to I–. Record configuration of DIP Switch (S1) positions 1 through 6. Place DIP Switch (S1) positions 1 through 6 to open.
  • Page 28 Omega Model CYTX231 User’s Manual This Page Intentionally Left Blank Service...
  • Page 29: Options And Accessories

    Omega Model CYTX231 User’s Manual CHAPTER 5 OPTIONS AND ACCESSORIES GENERAL This chapter lists Model CYTX231 enclosures, options, accessories, sensors, wires, and special equipment. ENCLOSURES MODEL DESCRIPTION OF ENCLOSURE VMEbus rack mount case with built-in power CYTX-Enclosure-12 supply for up to 12 Model CYTX231's. ACCESSORIES MODEL DESCRIPTION OF ACCESSORY...
  • Page 30: Wires

    Omega Model CYTX231 User’s Manual WIRES DESCRIPTION OF CABLE CYW4-32 (*) Quad-Lead™ Cryogenic Wire. Phosphor-bronze wire, flat, 32 AWG, 0.203 mm (0.008 inch) diameter. CYW4-36 (*) Quad-Lead™ Cryogenic Wire. Phosphor-bronze wire, flat, 36 AWG, 0.127 mm (0.005 inch) diameter. — Any quality dual shield twisted pair wire for dewar to Model CYTX231 connector.
  • Page 31: Appendix A - Model Cytx231 Curve Tables

    Omega Model CYTX231 User’s Manual APPENDIX A MODEL CYTX231 CURVE TABLES Table A-1. Standard Diode Curves Break- DT-670 Curve Curve 10 point No. Temp.(K) Voltage Temp.(K) Voltage 499.9 0.00000 499.9 0.00000 475.0 0.14703 475.0 0.09032 445.0 0.21870 460.0 0.12536 400.0 0.32600 435.0 0.18696...
  • Page 32 Omega Model CYTX231 User’s Manual Table A-2. Series PT-100 Platinum Resistance Curve Temperature in kelvin, resistance in ohms, and slope in ohms per kelvin. Temperature coefficient (237.15 to 373.15): 0.00385 ohms/ohms•K. Conforms to DIN 43760:1980; IEC 751:1983: and BS 1904:1984. Class B T (K) ±K...
  • Page 33 Omega Model CYTX231 User’s Manual APPENDIX B GLOSSARY OF TERMINOLOGY absolute zero. The temperature of –273.15 °C, or –459.67 °F, or 0 K, thought to be the temperature at which molecular motion vanishes and a body would have no heat energy. accuracy.
  • Page 34: Appendix B - Glossary Of Terminology

    Omega Model CYTX231 User’s Manual error. Any discrepancy between a computed, observed, or measured quantity and the true, specified, or theoretically correct value or condition. excitation. Either an AC or DC input to a sensor used to produce an output signal. Common excitations include: constant current, constant voltage, or constant power.
  • Page 35 Omega Model CYTX231 User’s Manual liquid helium (LHe). Used for low temperature and superconductivity research: minimum purity 99.998%. Boiling point at 1 atm = 4.2 K. Latent heat of vaporization = 2.6 kilojoules per liter. Liquid density = 0.125 kilograms per liter. EPA Hazard Categories: Immediate (Acute) Health and Sudden Release of Pressure Hazards DOT Label: Nonflammable Gas...
  • Page 36 Omega Model CYTX231 User’s Manual sensitivity. The ratio of the response or change induced in the output to a stimulus or change in the input. Temperature sensitivity of a resistance temperature detector is expressed as S = dR/dT. setpoint. The value selected to be maintained by an automatic controller. SI.

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