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Lake Shore 234 User Manual

Temperature transmitter/monitor
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Temperature Transmitter/Monitor
For Use with the Following Lake Shore Sensors:
Series CGR Carbon-Glass Resistance Temperature Sensors
Series CX Cernox™ Resistance Temperature Sensors
Series GR-200 Germanium Resistance Temperature Sensors
Methods and apparatus disclosed and described herein have been developed solely on company funds of Lake
Shore Cryotronics, Inc. No government or other contractual support or relationship whatsoever has existed which in
any way affects or mitigates proprietary rights of Lake Shore Cryotronics, Inc. in these developments. Methods and
apparatus disclosed herein may be subject to U.S. Patents existing or applied for. Lake Shore Cryotronics, Inc.
reserves the right to add, improve, modify, or withdraw functions, design modifications, or products at any time without
notice. Lake Shore shall not be liable for errors contained herein or for incidental or consequential damages in
connection with furnishing, performance, or use of this material.
Rev. 1.7
User's Manual
Model 234
Temperature Transmitter
Model 234D
Includes Coverage for:
Model 2308-01 Benchtop Enclosure
Model 2308-12 VMEbus Rackmount Case
Lake Shore Cryotronics, Inc.
575 McCorkle Boulevard
Westerville, Ohio 43082-8888 USA
E-Mail Addresses:
sales@lakeshore.com
service@lakeshore.com
Visit Our Website:
www.lakeshore.com
Fax: (614) 891-1392
Telephone: (614) 891-2243
P/N 119-026
and
1 March 2016

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Summary of Contents for Lake Shore 234

  • Page 1 Lake Shore shall not be liable for errors contained herein or for incidental or consequential damages in connection with furnishing, performance, or use of this material.
  • Page 2 Warranty Period and the Product is shipped freight prepaid, Lake Shore will, at its option, either repair or replace the Product if it is so defective without charge to the owner for parts, service labor or associated customary return shipping cost. Any such replacement for the Product may be either new or equivalent in performance to new.

  • Page 3: Table Of Contents

    Lake Shore Model 234/234D User’s Manual TABLE OF CONTENTS Chapter/Paragraph Title Page INTRODUCTION ................1-1 General ................1-1 Model 234 General Description ........1-1 Model 234D General Description ........1-3 Model 2308-1 Enclosure Description......1-8 Model 2308-12 Case Description ........1-8 INSTALLATION ................
  • Page 4 Model 234D Dimensions & Front Panel ........1-4 Model 2308-1 Enclosure Physical Dimensions ......1-9 Model 2308-12 Case Physical Dimensions ......1-10 Typical Model 234 to Sensor Connections ....... 2-3 Typical Wall Plug-In Power Supply .......... 2-6 Model 234 DIP Switch (S1) Settings ........3-1 Serial I/O (RJ11) Connector Pin Definitions ......

  • Page 5: Introduction

    The Model 234 excites the sensor with a constant voltage of 10 mV or less to minimize the effects of sensor self-heating at low temperatures. Introduction...
  • Page 6 VME bus connector. The Model 234 is built on a standard A-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.

  • Page 7: Model 234D General Description

    6-digit LED Display. It maintains full transmitter capabilities, serial interface commands, and curve format of the standard Model 234. The display is updated at one half the rate of the transmitter output.
  • Page 8 Lake Shore Model 234/234D User’s Manual Figure 1-2. Model 234D Front Panel and Dimensions Introduction...
  • Page 9 Update Rate: 4 readings / second (2 readings / second on Scale 0 only). CalCurve Storage: 1 curve, factory or field loaded into EEPROM via serial interface. Example Lake Shore Sensor: CGR-1-1000 with 1.4L calibration Temperature Range: 1.4 K – 325 K with CGR-1-1000 Standard Sensor Curve: Requires Calibrated Sensor and CalCurve Typical Sensor Sensitivity: –700 Ω/K at 4.2 K...
  • Page 10 Lake Shore Model 234/234D User’s Manual Table 1-1. Model 234 Specifications (Continued) Typical CalCurve Target Accuracy: ±1 mK below 10 K ±100 mK 40 K - 100 K ±5 mK 10 K - 20 K ±1 K above 100 K ±25 mK 20 K - 40 K...
  • Page 11 Power requirement: +5 (±0.25) VDC, 500 mA (234) / 750 mA (234D) 234 Size: 12.8 cm (5 in.) high, 18.5 cm (7.3 in.) deep, 3 cm (1.2 in.) wide 234D Size: 4.4 cm (1.7 in.) high, 23 cm (9 in.) deep, 14 cm (5.5 in.) wide 234 Mounting: Euroboard end panel and back plane.

  • Page 12: Model 2308-1 Enclosure Description

    Figure 1-4). It is the same enclosure that houses the Model 234D. MODEL 2308-12 CASE DESCRIPTION The Model 2308-12 VMEbus Rackmount Case holds up to twelve Model 234 Temperature Transmitters. A +5 VDC power supply with universal input comes with the case. See Table 1-2 and Figure 1-5. See Paragraph 2.5 for further information on the built-in power supply.

  • Page 13: Model 2308-1 Enclosure Physical Dimensions

    Lake Shore Model 234/234D User’s Manual Figure 1-3. Model 2308-1 Enclosure Physical Dimensions Introduction...

  • Page 14: Model 2308-12 Case Physical Dimensions

    Lake Shore Model 234/234D User’s Manual Figure 1-4. Model 2308-12 Case Physical Dimensions 1-10 Introduction...

  • Page 15: Installation

    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 Lake Shore for shipping and packing instructions.

  • Page 16: Sensor Installation Recommendations

    Lake Shore Model 234/234D User’s Manual SENSOR INSTALLATION RECOMMENDATIONS See the Lake Shore Product Catalog for installation details and sensor specifications. Call Lake Shore for copies of application notes or sensor installation questions. 1. Do not ground the sensor. 2. Shield leads and connect shield wire to SHIELD on screw terminal connector only.

  • Page 17: 2.3.2 Connecting Leads To The Sensor

    Always use the four-lead measurement configuration with Series CGR Carbon-Glass and Series GR Germanium Resistance Temperature Sensors attached to the Model 234. Figure 2-1. Typical Model 234 to Sensor Connections Installation...

  • Page 18: Proper Shielding Techniques

    2.3.4 Proper Shielding Techniques Since the Model 234 excitation voltage is so low, shield resistance sensor leads to avoid inducing measurement errors due to AC noise. Use twisted pair cable, one pair for current and one for voltage, with an overall shield.

  • Page 19: Calcurve

    CalCurve is present, Place the T/R switch in the T position. See Paragraph 3.1 for output current temperature ranges. The factory stores the optional Model 8001-234 CalCurve in the unit if it is ordered with the unit. The Curve EPROM (see Figure 5-4) is labeled with the sensor serial number.

  • Page 20: Typical Wall Plug-In Power Supply

    Lake Shore Model 234/234D User’s Manual Figure 2-2. Typical Wall Plug-In Power Supply Installation...

  • Page 21: Operation

    (S1). To access the PCB, use a flat blade screw driver to loosen the top- and bottom-most screws on the front panel of a Model 234 mounted in a Model 2308-1 or -12 enclosure, or the back panel of a Model 234D. Then see Figure 5-3 for location of Switch S1.

  • Page 22: Output To Temperature Conversion

    Lake Shore Model 234/234D 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 translates output into voltage scaled up to 10 V. For a 0-10 V output, use a 500 Ω...

  • Page 23: Output To Log(R) Conversion

    When no CalCurve is present, set the T/R switch to R. The output current or voltage are directly proportional to the log of the resistance reading. This is the transmitter output for both the Model 234 and 234D. Only the display of the Model 234D is resistance only.
  • Page 24 Lake Shore Model 234/234D User’s Manual This Page Intentionally Left Blank Operation...

  • Page 25: Remote Operation

    Interface Commands in Paragraph 4.2. SERIAL INTERFACE The Model 234 has a serial interface for communications with a host computer. It is an unbalanced (single ended), non-terminated line used over short distances (typically 10 feet or less). The Model 234 serial interface complies with the electrical format of the RS-232C Interface Standard.

  • Page 26: Serial Interface Operation

    Serial Interface Operation The host computer initiates serial interface link operation; it transmits either a command or a query to the Model 234. The Model 234 stores the characters in a 16 character buffer until the carriage return (CR), line feed (LF) terminator sequence.

  • Page 27: Quickbasic Programming Considerations

    Lake Shore Model 234/234D User’s Manual When programming a Model 234 from the serial interface, consider the following: • The serial interface transmission mode (asynchronous half duplex), format (10 bits per character; 1 start, 8 data, no parity, and 1 stop), and baud rate (9600) are factory set as outlined in Paragraph 4.1.

  • Page 28: Quickbasic Sample Program

    Lake Shore Model 234/234D User’s Manual 4.1.4 QuickBasic Sample Program The following program for a PC is an interactive program that prompts the user for a command to send the unit and displays the response. A query must be part of the command to get a response from the unit.

  • Page 29: Serial Interface Command Summary

    Lake Shore Model 234/234D User’s Manual SERIAL INTERFACE COMMAND SUMMARY This Paragraph summarizes Model 234 Serial Interface Commands. Command Function QIDN? Identification Query QRST Reset Command Program Curve Breakpoint Curve Breakpoint Query Calibrate Resistance Measurement Input Set Current Output To Zero...
  • Page 30 Lake Shore Model 234/234D User’s Manual Q IDN? Identification Query QIDN? Input: Returned: Manufacturer,model number,0,software date Remarks: Identifies instrument model number and software level. The “0” in the returned syntax is in place of the serial number. Example: LSCI,MODEL234,0,031093 Q RST...
  • Page 31 Lake Shore Model 234/234D User’s Manual Set Current Output to Zero Input: Returned: Nothing Remarks: Holds current output at zero until another command or query is sent. Set Current Output to 4 mA Input: Returned: Nothing Remarks: Holds current output at 4 mA until another command or query is sent.
  • Page 32 Lake Shore Model 234/234D User’s Manual SCALE? Resistance Measurement Scale Query Input: SCALE? Returned: 0 thru 9 Remarks: Queries resistance measurement scale. Program Curve Identification Input: SID XXXXXXXX Returned: Nothing Remarks: Programs the 8-character curve identification. When an optional CalCurve is stored, the sensor serial number is usually entered as the curve identification.

  • Page 33: Service

    500 mA. Also verify that OUT+ and SHIELD are not connected to each other. Due to extensive protection circuitry installed in Model 234, all the above problems eventually cause the 1 A slow blow fuse to burn out. After correcting the cause, replace the blown fuse with identical size and type.

  • Page 34: Model 234 Connectors

    Lake Shore Model 234/234D User’s Manual MODEL 234 CONNECTORS There are four connectors on the Model 234. The three front panel connectors are the 8-pin terminal block (J3), RJ11 Serial I/O connector (J4), and the power connector (J2). See Figure 5-1. The Serial I/O Connector pins are defined in Figure 4-1.

  • Page 35: Calcurve Field Installation

    +5 VDC +5 VDC Figure 5-2. VMEbus Connector Details CALCURVE FIELD INSTALLATION The Model 8001-234 CalCurve is stored in an Electrically Erasable Programmable Read Only Memory (EEPROM). Use the following procedure to install or replace the CalCurve EEPROM. CAUTION: Disconnect power to the instrument before performing this procedure.
  • Page 36 Lake Shore Model 234/234D User’s Manual Figure 5-3. Model 234 PCB Details Service...

  • Page 37: Calibration

    The section covers Required Test Equipment in Paragraph 5.4.1, Reference Calibration procedure is provided in Paragraph 5.4.2. Finally, the calibration procedure is provided in Paragraph 5.4.3. See Figure 5-3 for the Model 234 PCB layout. Allow 5 minutes warm-up before performing any calibration procedures.

  • Page 38: Required Equipment

    5V is on the sleeve, the return in the center pin. 3. The mating screw terminal to the Model 234 front panel signal connector. 4. 1 Ω, 10 Ω, 100 Ω, 1 kΩ, 10 kΩ, and 100 kΩ 0.01% resistors to simulate the sensor for calibration.
  • Page 39 3. Preparation. a. Connect the 1 kΩ calibration resistor to the screw terminal SENSOR I+ and SENSOR I– to simulate a sensor load to the Model 234. Use a shorting wire to connect SENSOR I+ to SENSOR V+, and another shorting wire to connect SENSOR I–...
  • Page 40 OUT– terminals. c. Connect the 1 kΩ calibration resistor to the screw terminal SENSOR I+ and SENSOR I– to simulate a sensor load to the Model 234. Use a shorting wire to connect SENSOR I+ to SENSOR V+, and another shorting wire to connect SENSOR I–...
  • Page 41 5.4.4 Calibration Using Serial Interface Calibration Commands Model 234 calibration consists of output calibration and input calibration. NOTE: Allow about 30 minutes for the Model 234 Temperature Transmitter to warm up before continuing with calibration. 1. Serial Interface Program a. Connect the Serial Port of the computer to the transmitter via the RJ11 connector.
  • Page 42 OUT– terminals. c. Connect the 1 kΩ calibration resistor to the screw terminal SENSOR I+ and SENSOR I– to simulate a sensor load to the Model 234. Use a shorting wire to connect SENSOR I+ to SENSOR V+, and another shorting wire to connect SENSOR I–...

  • Page 43: Calibration Verification

    Lake Shore Model 234/234D User’s Manual 5.4.5 Calibration Verification 1. Connect the DVM negative lead to OUT–, and positive lead to OUT+. Make sure that the 500 Ω load resistor is also connected to OUT+ and OUT– terminals. 2. Make sure that the I/V to the V position (closed), and the T/R switch to R (closed).
  • Page 44 Lake Shore Model 234/234D User’s Manual This Page Intentionally Left Blank 5-12 Service...

  • Page 45: Options And Accessories

    Lake Shore Model 234/234D User’s Manual CHAPTER 6 OPTIONS AND ACCESSORIES GENERAL This chapter lists Model 234 enclosures, options, accessories, sensors, wires, and special equipment. ENCLOSURES Model Description Of Enclosure 2308-1 Benchtop Enclosure for use with one Model 234 PCB.

  • Page 46: Accessories

    Lake Shore Model 234/234D User’s Manual ACCESSORIES Model Description Of Accessory Resistor, Precision, 500 Ω, ±0.02% 103-626 106-739 Input Terminal Mating Connector 2001 Modular Cable, RJ-11 to RJ-11, 4.6 m (14 ft.) long 2002 Adapter, RJ-11 to DB-25, for RS-232C Interface...

  • Page 47: Sensors

    Lake Shore Model 234/234D User’s Manual SENSORS Sensor No. Description Of Sensor Series CGR Carbon-Glass Resistance Temperature Sensors is a highly reproducible sensor that can be used from 1.0 K to 100 K and above in magnetic fields up to 19 tesla.
  • Page 48 Lake Shore Model 234/234D User’s Manual This Page Intentionally Left Blank Options & Accessories...

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