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AMI 420 Installation, Operation And Maintenance Instructions

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1 Cover Page
EXCELLENCE IN MAGNETICS AND CRYOGENICS
MODEL 420 POWER SUPPLY
PROGRAMMER
INSTALLATION, OPERATION, AND
MAINTENANCE INSTRUCTIONS
American Magnetics, Inc.
PO Box 2509, 112 Flint Road, Oak Ridge, TN 37831-2509, Tel: 865 482-1056, Fax: 865 482-5472
Rev. 7, July 2002

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  • Page 1 1 Cover Page EXCELLENCE IN MAGNETICS AND CRYOGENICS MODEL 420 POWER SUPPLY PROGRAMMER INSTALLATION, OPERATION, AND MAINTENANCE INSTRUCTIONS American Magnetics, Inc. PO Box 2509, 112 Flint Road, Oak Ridge, TN 37831-2509, Tel: 865 482-1056, Fax: 865 482-5472 Rev. 7, July 2002...

  • Page 3: Declaration Of Conformity

    1 Declaration of Conformity Model 420 Power Supply Programmer Declaration of Conformity Application of Council Directive: 72/73/EEC Standard to which Conformity is Declared: EN 61010-1: 1993 w/A1, A2 Manufacturer’s Name: American Magnetics, Inc. Manufacturer’s Address: 112 Flint Road, P.O. Box 2509 Oak Ridge, TN 37831-2509 U.S.A.
  • Page 5 In the event of failure occurring during normal use, AMI, at its option, will repair or replace all products or components that fail under warranty, and such repair or replacement shall constitute a fulfillment of all AMI liabilities with respect to its products.

  • Page 7: Table Of Contents

    Standard Remote Interfaces ......... 2 1.1.6 Programmable Safety Features ........2 Front Panel Layout ..............3 Rear Panel Layout..............5 Model 420 Specifications @ 25 °C .......... 7 Operating Characteristics............9 1.5.1 Single-Quadrant Operation .......... 9 1.5.2 Dual-Quadrant Operation........... 10 1.5.3...
  • Page 8 Table of Contents Special Configurations.............31 2.6.1 Superconducting Magnets without a Persistent Switch ................31 2.6.2 Short-Circuit or Resistive Load ........32 Power-Up and Test Procedure..........33 Operation .................37 Default Display Modes.............37 3.1.1 Entering Numerical Values .........38 3.1.2 Menu Option Selection..........39 3.1.3 Exiting Menus ..............39 Setup Menu Descriptions ............39 3.2.1 Supply Setup Submenu..........40...
  • Page 9 4.6.3 Execution Errors............94 4.6.4 Device Errors ............... 94 Service ..................95 Model 420 Maintenance ............95 Model 420 Troubleshooting Hints .......... 95 Additional Technical Support ..........103 Return Authorization ............104 Appendix................105 A.1 Magnet Station Connectors ..........105 A.2 Auxiliary LHe Level/Temperature Connectors...
  • Page 10 Figure 2-4 System interconnect diagram for a unipolar supply with an AMI Model 610/630 energy absorber and a current reversing switch............25 Figure 2-5 System interconnect diagram for the AMI Model 4Q-05100 power supply................27 Figure 2-6 System interconnect diagram for the Kepco BOP series power supply................29...
  • Page 11 Example Setup Configuration ..........51 Table 3-5 Ramping states and descriptions........... 53 Table 3-6 Summary of limits and defaults for the Model 420....63 Table 4-1 Bit definitions for the Status Byte register......71 Table 4-2 Bit definitions for the Standard Event register..... 74...

  • Page 12: List Of Tables

    List of Tables Rev. 7...

  • Page 13: Foreword

    Since it is not possible to cover all equipment combinations for all magnet systems, the most common configurations are discussed and the user is encouraged to contact an authorized AMI Technical Support Representative for information regarding specific configurations not explicitly covered in this manual.

  • Page 14: Applicable Hardware

    Applicable Hardware Applicable Hardware The Model 420 has been designed to operate with a wide variety of switch mode and linear power supplies from a variety of manufacturers. However, not all compatible power supplies have been tested. The Model 420...
  • Page 15 Foreword General Precautions Cryogenic liquids, due to their extremely low temperatures, will also burn the skin in a similar manner as would hot liquids. Never permit cryogenic liquids to come into contact with the skin or allow liquid nitrogen to soak clothing.

  • Page 16: Safety Summary

    The Model 420 Programmer has been designed with safety interlocks to assist the operator in safe operation, but these designed-in features cannot replace an operator’s...
  • Page 17 Foreword Safety Summary Recommended Safety Equipment ‡ First Aid kit ‡ Fire extinguisher rated for class C fires ‡ Leather gloves ‡ Face shield ‡ Signs to indicate that there are potentially damaging magnetic fields in the area and that there are cryogens are in use in the area. Safety Legend Instruction manual symbol: the product is marked with this symbol when it is necessary for you to refer to the instruction...
  • Page 18 Foreword Safety Summary Rev. 7...

  • Page 19: Introduction

    The menus are also presented in a logical fashion so that the operation of the Model 420 is intuitive to the user. The provision of a velocity-sensitive rotary encoder on the front panel also allows the operator to fine-adjust many of the operating parameters of the magnet system.

  • Page 20: Flexible Design

    1.1.6 Programmable Safety Features The Model 420 Programmer is designed to allow the operator to program the instrument from the front panel or remotely with operational parameters which must not be exceeded for the given conditions of the system.

  • Page 21: Front Panel Layout

      $ 3URJUDPPHG &XUUHQW $  9V B Table 1-1. Front Panel Description 40 x 2 Dot Matrix LCD Display w/ LED Magnet Voltage Meter Zero Adjust Backlight Voltage Limit LED Persistent Switch Heater Control Current/Field Limit LED Quench RESET/ZERO Mode Switch 4 Row x 5 Column Keypad 10 Rotary Encoder Dial Power Switch...
  • Page 22 Introduction Front Panel Layout Rev. 7...

  • Page 23: Rear Panel Layout

    Table 1-2. Rear Panel Description Current Shunt Terminals Program Out BNC Female Connector RS-232/422 25-pin Female D-sub Dual Magnet Station 25-pin Female Connector D-sub Connectors IEEE-488 Female Connector Dual Auxiliary LHe Level/Temp 9-pin Male D-sub Connectors Quench I/O 9-pin Female D-sub Input Power IEC-320 Male Connector Connector...
  • Page 24 Introduction Rear Panel Layout Rev. 7...

  • Page 25: Model 420 Specifications @ 25 °C

    Introduction Specifications 1.4 Model 420 Specifications @ 25 °C Standard Model 420 Configurations: Programmable Limits Magnet Current Control Parameters ± 5 A ± 10 A ± 100 A ± 200 A ± 300 A ± 600 A ± 2000 A 10 µA...
  • Page 26 Introduction Specifications Power Requirements 100-120 or 200-240 VAC ±10% Primary: 50 - 60 Hz, 50 VA max Memory Backup Battery: 3.6 Volt AA Lithium Cell Physical Dimensions: 89 mm H x 483 mm W x 191 mm D (3.5" H x 19" W x 10.75" D) Weight: 4.2 kg (9.2 lbs.) Torque Limits on Current...

  • Page 27: Operating Characteristics

    The simplest form of a programmer-power supply system is the single quadrant system as illustrated in Figure 1-2. The system is comprised of a Model 420 Programmer, unipolar power supply, and superconducting magnet. This system allows current to flow in a single direction in the magnet thereby giving a magnetic field vector of varying magnitude but in a single direction.

  • Page 28: Dual-Quadrant Operation

    Magnet Switch Unipolar Coil(s) (optional) Power Supply Energy Model 420 Absorber Shunt Figure 1-3. Dual-Quadrant Magnet System 1.5.3 Simulated Four-Quadrant Operation In the simulated four-quadrant programmer-power supply system, as show in Figure 1-4, a mechanical current reversing switch is included, usually in the energy absorber.

  • Page 29: True Four-Quadrant Operation

    AC power loss or quenches. Misc. Line Losses Current Persistent Magnet Switch Four-Quadrant Coil(s) (optional) Power Supply Model 420 Shunt Figure 1-5. True Four-Quadrant System Rev. 7...
  • Page 30 Introduction Operating Characteristics Rev. 7...

  • Page 31: Installation

    If the instrument is to be used as a table top model, place the instrument on a flat, secure surface. The Model 420 uses an internal fan for forced-air cooling. Allow at least 1/8" spacing beneath the unit for proper ventilation.

  • Page 32: Power Requirements

    Attach the rack mount adapter pieces to the sides of the instrument by reinstalling the screws. 2. Install the Model 420 in a 19" wide instrument rack by securing the front panel to the rail in each of the four corners with mounting hardware supplied by the cabinet manufacturer.

  • Page 33: Collecting Necessary Information

    An example of the data to be entered and how it is entered is described in paragraph 3.2.5 on page 50. If the Model 420 was purchased as part of a magnet system, essential data has already been entered at the AMI factory and a configuration sheet should be provided detailing the settings.

  • Page 34: Unipolar Supply Without Energy Absorber

    (8) and the magnet station connector J7A or J7B. f. Install an instrumentation cable between the LHe/Temp connectors J8A and/or J8B on the rear of the Model 420 and the Model 13x Liquid Helium Level Instrument and/or temperature instrument (9).

  • Page 35: Figure 2-1 System Interconnect Diagram For A Unipolar Supply Without An Energy Absorber

    AMI Model 12100PS Model 420 Rear Panel Unipolar Supply 6 @SD86IÃ 6BI@UD8TÃDI8 P6FÃSD9B@ÃUIÃVT6 8VSS@IUÃTCVIU 6BI@UÃTU6UDPI GCrÃG@W@GU@ Q 8PII@8UPST 8PII@8UPST DIQVUÃQPX@S GDI@)Ã$%ÃC“Ã$ÃW6Ã 6Y 67TPS7@S D@@@#'' WPGU6B@ÃÉ QSPBS6 ÃPVU E&6 ST!"! RV@I8CÃDP  !ÃW !!#ÃW E&7 T@G@8UPSÃTXDU8CÃDITD9@ AMI Model 13x Rear Panel RS-232 6H@SD86IÃH6BI@UD8TÃDI8...

  • Page 36: Unipolar Supply With Ami Model 601 Energy Absorber

    Connect the negative ( − ) vapor-cooled current lead (5) to the positive (+) shunt terminal (6) on the back of the Model 420. d. Connect the negative ( − ) shunt terminal (7) of the Model 420 to the negative (NEG) output lug of the power supply (8).

  • Page 37: Figure 2-2 System Interconnect Diagram For A Unipolar Supply With An Ami Model 601 Energy Absorber

    Unipolar Supply AMI Model 13x Rear Panel 6H@SD86IÃH6BI@UD8TÃDI8 RS-232 P6FÃSD9B@ÃUIÃÃVT6 8PHHVID86UDPIT 8PIUSP @SÃPVUQVU DIQVUÃQPX@S T@ITPS ( "!ÃW68 '!%#ÃW68 DI@ÃWP U6B@Ã 6ÃH6Y $%ÃC“ÃT@ ÃTXÃDITD9@ Superconducting Magnet Figure 2-2. System interconnect diagram for a unipolar supply with an AMI Model 601 Energy Absorber.
  • Page 38 J7A or J7B on the rear of the Model 420. g. Install an instrumentation cable between the LHe/Temp connectors J8A and/or J8B on the rear of the Model 420 and the Model 13x Liquid Helium Level Instrument and/or temperature instrument (11).

  • Page 39: Unipolar Supply With Ami Model 600/620 Energy Absorber

    Model 420 (see the torque specifications on page 7). Overtightening can result in damage to the terminals. c. Connect the negative ( − ) shunt terminal (5) of the Model 420 to the negative (NEG) output lug of the power supply (6).

  • Page 40: Figure 2-3 System Interconnect Diagram For A Unipolar Supply With An Ami Model 600/620 Energy Absorber

    AMI Model 13x Rear Panel RS-232 6H@SD86IÃH6BI@UD8TÃDI8 P6FÃSD9B@ÃUIÃÃVT6 8PHHVID86UDPIT 8PIUSP @SÃPVUQVU DIQVUÃQPX@S T@ITPS ( "!ÃW68 '!%#ÃW68 DI@ÃWP U6B@Ã 6ÃH6Y $%ÃC“ÃT@ ÃTXÃDITD9@ AMI Model 600 Energy Absorber Superconducting Magnet Figure 2-3. System interconnect diagram for a unipolar supply with an AMI Model 600/620 Energy Absorber.
  • Page 41 J7A or J7B on the rear of the Model 420. h. Install an instrumentation cable between the LHe/Temp connectors J8A and/or J8B on the rear of the Model 420 and the Model 13x Liquid Helium Level Instrument and/or temperature instrument (13).

  • Page 42: Unipolar Supply With Ami Model 610/630 Energy Absorber And Current Reversing Switch

    Model 420 (see the torque specifications on page 7). Overtightening can result in damage to the terminals. c. Connect the negative ( − ) shunt terminal (5) of the Model 420 to the negative ( − ) output lug of the power supply (6).

  • Page 43: Figure 2-4 System Interconnect Diagram For A Unipolar Supply With An Ami Model 610/630 Energy Absorber And A Current Reversing Switch

    8PIUSP @SÃPVUQVU DIQVUÃQPX@S T@ITPS ( "!ÃW68 '!%#ÃW68 DI@ÃWP U6B@Ã 6ÃH6Y $%ÃC“ÃT@ ÃTXÃDITD9@ Superconducting AMI Model 610 Energy Absorber Magnet Figure 2-4. System interconnect diagram for a unipolar supply with an AMI Model 610/630 energy absorber and a current reversing switch.

  • Page 44: High-Current Four-Quadrant Supply

    (13) and the magnet station connector J7A or J7B. Install an instrumentation cable between the LHe/Temp connectors J8A and/or J8B on the rear of the Model 420 and the Model 13x Liquid Helium Level Instrument and/or temperature instrument (14).

  • Page 45: Figure 2-5 System Interconnect Diagram For The Ami Model 4Q-05100 Power Supply

    AMI Model 13x Rear Panel RS-232 H@SD8 IÃH BI@UD8TÃDI8 P FÃSD9B@ÃUIÃÃVT  8PHHVID8 UDPIT 8PIUSPGG@SÃPVUQVU DIQVUÃQPX@S T@ITPS ( "!ÃW 8 '!%#ÃW 8 GDI@ÃWPGU B@Ã ÃH Y $%ÃC“ÃT@GÃTXÃDITD9@ Superconducting Magnet Figure 2-5. System interconnect diagram for the AMI Model 4Q-05100 power supply.

  • Page 46: Low-Current, High-Resolution Four-Quadrant Supply

    (8) and the magnet station connector J7A or J7B. f. Install an instrumentation cable between the LHe/Temp connectors J8A and/or J8B on the rear of the Model 420 and the Model 13x Liquid Helium Level Instrument and/or temperature instrument (9).

  • Page 47: Figure 2-6 System Interconnect Diagram For The Kepco Bop Series Power Supply

    Kepco BOP 20-5/10M Supply Model 420 Rear Panel KEPCO BIPOLAR OPERATIONAL POWER SUPPLY/AMPLIFIER OUT OUT GRD NET. COM VOLTAGE CURRENT 6 @SD86Ià 6BI@UD8TÃDI8 VOLTAGE CONTROL CURRENT CONTROL MODE oà P6FÃSD9B@ÃUIÃVT6 8VSS@IUÃTCVIU 6BI@UÃTU6UDPI GCrÃG@W@GU@ Q 8PII@8UPST 8PII@8UPST DIQVUÃQPX@S GDI@)Ã$%ÃC“Ã$ÃW6à 6Y REMOTE...
  • Page 48 (8) and the magnet station connector J7A or J7B. f. Install an instrumentation cable between the LHe/Temp connectors J8A and/or J8B on the rear of the Model 420 and the Model 13x Liquid Helium Level Instrument and/or temperature instrument (9).

  • Page 49: Third-Party Power Supplies

    Installation Magnets w/o Persistent Switch 2.5.7 Third-Party Power Supplies The Model 420 has been designed to function with a wide variety of third- party power supplies. Please contact an AMI Technical Support Representative for compatibility with specific models. Custom modifications can be made to accommodate supplies that are not compatible with the standard Model 420 configurations.

  • Page 50: Short-Circuit Or Resistive Load

    Note that when operating with a superconducting magnet in the circuit, the integration gain of the Model 420 will be adequate to quickly “bias” the Model 601 and achieve a proper current ramping profile. Rev. 7...

  • Page 51: Power-Up And Test Procedure

    This will allow rudimentary power supply checks without energizing the superconducting magnet. 3. Energize the Model 420 by placing the power switch in the , (ON) position. 4. Enter a stability setting of 100% in the Load setup menu. Refer to paragraph 3.2.2.1 on page 44 for more information.
  • Page 52 Model 420 is normally more accurate than the power supply shunt. The Model 420 is calibrated to 0.1% of the actual current, which is typically five times more accurate than most integrated power supply shunts.
  • Page 53 Installation Power-Up Procedure 18. Reset the stability setting and ramp rate of the Model 420 to an appropriate value for the magnet to be operated. Then turn off the Model 420. 19. Remove the short from the power supply leads and connect the leads to the vapor-cooled current leads of the magnet.
  • Page 54 Installation Power-Up Procedure Rev. 7...

  • Page 55: Operation

    3 Operation This section describes each display and operating mode of the Model 420 instrument and the related functions. Every available menu is illustrated and described in detail. An example setup of the instrument is presented in paragraph 3.2.5 on page page 50. An example ramping operation is presented in paragraph 3.3.6 on page 57.

  • Page 56: Entering Numerical Values

    Operation Entering Values The operating (shunt) current is displayed in Amperes and may alternately be displayed as estimated field in kilogauss (or Tesla) in display mode 3 or 4 if a coil constant has been specified in the setup (see paragraph 3.2.2.2).

  • Page 57: Menu Option Selection

    Operation Setup Menu 3.1.2 Menu Option Selection Some menus may require the user to cycle through and select from a list of predefined options. Such menus will display a cursor which indicates that a list of predefined options are available from which to select. 237,21 Pressing the key moves the cursor forward within the list.

  • Page 58: Supply Setup Submenu

    If using a standard power supply supported by AMI, selecting a power supply within the Select Power Supply menu sets all the remaining parameters in the supply menu according to Table 3-2.

  • Page 59: Table 3-2 Available Select Power Supply Options

    If a change is attempted above this current, the Model 420 will beep and ignore the keypress. Power supply selection should also preferably be performed with the power supply off for maximum safety.

  • Page 60: Figure 3-3 Example Power Supply Operating Ranges

    Setup Menu : Supply AMI 12100PS OPERATING RANGE AMI 4Q05100PS OPERATING RANGE -200 -200 AMI 12100PS + MODEL 601 ENERGY ABSORBER OPERATING RANGE Figure 3-3. Example power supply operating ranges. 3.2.1.2 Min Output Voltage  $ × 0LQ 2XWSXW 9ROWDJH 9 ...

  • Page 61: Table 3-3 Predefined Voltage-To-Voltage Mode Input Range Ranges

    -5.000 to +5.000 -10.000 to +10.000 +0.000 to -5.000 1. The minimum and maximum output currents are bounded by the specific Model 420 configuration purchased. See page 7 for the specifications for each configuration. The entered value cannot exceed the programmable limits.

  • Page 62: Load Setup Submenu

    The stability setting is specified in percent and controls the transient response and stability of the system. The valid range is from 0.0 to 100.0%. The default value is 0.0% unless preset by AMI. The chart below may be used as a guide to set the stability setting for magnets with a persistent switch installed.

  • Page 63: Figure 3-4 Example Limits Setup

    Figure 3-4 below. Ã Current Limit (A) -200 EXAMPLE LIMITS ±2.5 ± Voltage Limit (V) AMI 4Q05100PS OPERATING RANGE Figure 3-4. Example limits setup. Note The Voltage Limit can be directly accessed via the front panel 92/7$*( /,0,7 key.
  • Page 64 During the persistent switch heating period, the Model 420 ramping functions are disabled. The time delay is necessary to ensure that the Model 420 will not switch to a higher gain required for proper magnet operation before the magnet is actually available in the circuit.
  • Page 65 YES and NO. The default value is NO. It is important for this setting to be correct since the internal gain tables of the Model 420 compensate for the additional load of the energy absorber if present. The increased gain when an energy absorber is present will decrease (but not eliminate) the time required for the system to “forward bias”...

  • Page 66: Misc Setup Submenu

    Operation Setup Menu : Misc 3.2.3 Misc Setup Submenu The Misc submenu allows specification of the display contrast setting, the ramp rate time units, and the field units. 3.2.3.1 Display Contrast  $ × 'LVSOD\ &RQWUDVW  9V Adjusts the contrast of the liquid crystal display from 0 to 100%.

  • Page 67: Comm Setup Submenu

     9V Specifies the IEEE-488 primary address of the Model 420. The valid range is from 0 to 30. The Model 420 should be assigned a unique primary address on the IEEE-488 bus. Enter a value or use the dial to adjust the value. The default primary address is 22. The Model 420 does not support secondary addressing.

  • Page 68: Example Setup

    The default setting is no handshaking. 3.2.5 Example Setup As a precursor to operating a superconducting magnet with the Model 420 programmer and power supply, all of the setup items should be reviewed and set if necessary with appropriate values for the connected superconducting magnet.

  • Page 69: Table 3-4 Example Setup Configuration

    If your magnet, programmer, and power supply were purchased as a system from AMI, the setup menus are preset by AMI to match the magnet purchased. Table 3-4 provides a summary of the Model 420 setup parameters for this example. Table 3-4. Example Setup Configuration...

  • Page 70: Ramping Functions

    A desired ramp rate should be selected by the operator and entered into the Model 420. A voltage limit should also be specified that is greater than or equal to the voltage calculated from the equations above (remember to account for power lead resistance).

  • Page 71: Table 3-5 Ramping States And Descriptions

    Operation Ramping Functions : Voltage Limit and Ramp Rate If manual mode operation is desired, press either the keys for manual control ramping up or ramping down, respectively. A voltage limit and ramp rate may be specified from quickly accessible menus from the front panel keypad.

  • Page 72: Ramping In Manual Mode

    The two keys labeled as control the ramping function in manual mode. If the is pressed and becomes illuminated, the Model 420 will ramp up at the ramp rate setting. The ramping may be paused by pressing the key again (or by pressing 5$033$86( ) to deactivate the manual up mode.

  • Page 73: Ramping In Programmed Mode

    Operation Ramping Functions : Manual and Programmed Modes If the key is pressed, the Model 420 will ramp down at the ramp rate setting. The ramping may be paused by pressing the key again (or by 5$033$86( pressing ) to deactivate the manual down mode.

  • Page 74: Ramp To Zero Mode

    When the dial is manipulated the Model 420 will follow at a compliance of less than or equal to the voltage limit. The ramp rate setting is not observed in this operational mode, however, the voltage limit is strictly observed and is never exceeded.

  • Page 75: Ramping Functions Example

    -50 A Figure 3-6. Example of ramping to two different programmed current settings. Point 1. The operating current is 0 A and the Model 420 is in the PAUSED 5$03 mode. The operator sets the programmed current to -30.000 A. The...
  • Page 76 Point 7. The operator increases the ramp rate and presses the =(52 key to begin ramping to zero current. The Model 420 automatically ramps the current to 0 A. Point 8. The Model 420 holds the operating current of 0 A when achieved 5(6(7=(52 until the key is deactivated.

  • Page 77: Persistent Switch Heater Control

    (see page 46). The nominal switch heating current is provided with the magnet specification sheet and may be entered in the Model 420 by accessing the load setup submenu (see paragraph 3.2.2.5). In addition to the heating current, the operator must also specify a heating time.

  • Page 78: Procedure For Entering Persistent Mode

    Most persistent switches cool to superconducting state in a few seconds if completely submerged in liquid helium. 6. Once the switch has cooled, the Model 420 may be used to ramp the current to zero at an increased ramp rate (since the magnet is no longer in the circuit).

  • Page 79: Optional Switching Of External Power Supply

    3.4.3 Optional Switching of External Power Supply The Model 420 offers the option of using an external power supply for the persistent switch heating current if the requirements for the switch heater exceed the capabilities of the integrated switch heating output of the Model 420.

  • Page 80: Disabling Automatic Quench Detection

    Under most operating conditions this will not damage any internal protection circuits of the magnet. If an actual quench condition occurs, the Model 420 will follow the magnet current to zero unless the operator intervenes. If the...

  • Page 81: Summary Of Operational Limits And Default Settings

    Table 3-6 provides a summary of the operational limits and the default setting for all Model 420 parameters. If the operator attempts to enter a value outside of the limits, the Model 420 will beep once and revert to the previous setting.
  • Page 82 Operation Summary of Operational Limits Rev. 7...

  • Page 83: Remote Interface Reference

    4 Remote Interface Reference The Model 420 provides both RS-232 and IEEE-488 interfaces as standard features. Upon request, the RS-232 port can be reconfigured for RS-422 operation. The serial and IEEE-488 interfaces may operated simultaneously. Separate output buffers are also provided for the serial and IEEE-488 return data.
  • Page 84 Remote Interface Reference SCPI Command Summary Status System Commands (see page 80 for more information) *STB? *SRE <enable_value> *SRE? *CLS *ESR? *ESE <enable_value> *ESE? *PSC {0|1} *PSC? *OPC *OPC? SETUP Configuration Commands (see page 82 for more information) CONFigure:STABility <percent> CONFigure:COILconst <value (kG/A, T/A)>...
  • Page 85 Remote Interface Reference SCPI Command Summary SETUP Configuration Queries (see page 82 for more information) SUPPly:VOLTage:MINimum? SUPPly:VOLTage:MAXimum? SUPPly:CURRent:MINimum? SUPPly:CURRent:MAXimum? SUPPly:TYPE? SUPPly:MODE? STABility? COILconst? CURRent:LIMit? PSwitch:CURRent? PSwitch:TIME? QUench:DETect? ABsorber? RAMP:RATE:UNITS? FIELD:UNITS? Rev. 7...
  • Page 86 Remote Interface Reference SCPI Command Summary Ramp Configuration Commands and Queries (see page page 85 for more information) CONFigure:VOLTage:LIMit <voltage> CONFigure:CURRent:PROGram <current> CONFigure:FIELD:PROGram <field (kG, T)> CONFigure:RAMP:RATE:CURRent <rate (A/s, A/min)> CONFigure:RAMP:RATE:FIELD <rate (kG/s, kG/min, T/s, T/min)> CONFigure:RAMP:CURRent <current>,<rate (A/s, A/min)> <field (kG, T)>,<rate (kG/s, kG/min, T/s, T/min)>...

  • Page 87: Programming Overview

    Programmable Instruments) IEEE standard. The SCPI standard is an ASCII-based specification designed to provide a consistent command structure for instruments from various manufacturers. The Model 420 also implements a status system for monitoring the state of the Model 420 through the Standard Event and Status Byte registers. 4.2.1...

  • Page 88: Scpi Status System

    SCPI Status System Many commands also require multiple keywords to traverse the tree structure of the entire Model 420 command set. For example, commands associated with a current setting require the prefix of CONFigure:CURRent. Note that a colon ( : ) separates the keywords. No spaces are allowed before or after the colon.

  • Page 89: Table 4-1 Bit Definitions For The Status Byte Register

    Value Definition 0 Not Used Always “0”. 1 Not Used Always “0”. 2 Quench Condition The Model 420 has detected a quench. 3 Serial Message The serial output buffer contains Available unread data. 4 IEEE-488 Message The IEEE-488 output buffer contains Available unread data.
  • Page 90 Remote Interface Reference SCPI Status System example, if the command *SRE 4 is sent to the Model 420, then if a quench detect subsequently occurs, the Model 420 will immediately generate an SRQ on the IEEE-488 bus. Bit 2 of the Status Byte register, indicating a quench condition, remains set until the quench condition is cleared via the front panel or by remote command.

  • Page 91: Standard Event Register

    The power is turned off and then back on, and the instrument was configured for *PSC 1 (power-on status clear). The enable register setting is persistent if the Model 420 is configured for *PSC 0 (no status clear on power-on).

  • Page 92: Command Handshaking

    4.2.4 Command Handshaking The Model 420 provides an internal command queue that can store up to 4 commands or queries. However, it is possible that the host computer can overwhelm the command queue by sending commands faster than the Model 420 can execute.
  • Page 93 Remote Interface Reference Command Handshaking If the operator has so configured the Standard Event and Status Byte enable registers, the *OPC command can generate an IEEE-488 service request when execution completes (see Figure 4-1). If using the serial port, the *OPC? query is a better alternative since a response is returned directly to the requesting communications interface.

  • Page 94: Rs-232/422 Configuration

    Communication Equipment) device since it transmits data on pin 3 and receives data on pin 2. The computer or terminal to which the Model 420 is attached must do the opposite, i.e., transmit on pin 2 and receive on pin 3 (the requirements for a DTE, or Data Terminal Equipment device).

  • Page 95: Flow Control Modes

    Software: Also referred to as XON/XOFF. Software handshaking uses special embedded characters in the data stream to control the flow. If the Model 420 is asked to return data, it continues data output until the XOFF character (13 Hex) is received. Once an XOFF character is received, an XON character (11 Hex) is required for data transmission to continue.

  • Page 96: Device Clear

    Model 420. The trigger functions supported by the Model 420 are documented in paragraph 4.5.8 on page 90. When a trigger command is received by the Model 420, the appropriate data is loaded into the output buffer(s) as selected by the *ETE <value>...

  • Page 97: Command Reference

    *RST command to reenable the front panel controls. Disables all front panel controls. If the Model 420 is in the remote mode, an asterisk ( ) will appear in the front panel display in the position just below the ramping character as shown below.

  • Page 98: Status System Commands

     N* b 6WDWXV 5DPSLQJ  9V 36ZLWFK +HDWHU 21 Figure 4-2. Illustration of asterisk annunciator indicating the Model 420 is in remote mode (all front panel controls are disabled). ‡ SYSTem:TIME? Returns the instrument’s time, in the format hh:mm:ss.ss, since the last power-on event or SYSTem:TIME:RESet command.
  • Page 99 Remote Interface Reference Status System Commands ‡ *SRE? The *SRE? query returns a decimal sum which corresponds to the binary- weighted sum of the bits enabled by the last *SRE command. ‡ *CLS Clears the Standard Event register and the error buffer. ‡...

  • Page 100: Setup Configuration Commands And Queries

    SUPPLY setup menu. Table 4-3. Return values and their meanings for the SUPPly:TYPE? query. Return Value Meaning AMI 12100PS AMI 12200PS AMI 4Q05100PS AMI 10100PS AMI 10200PS HP 6260B Kepco BOP 20-5M Kepco BOP 20-10M Xantrex XFR 7.5-140...

  • Page 101: Table 4-4 Return Values And Their Meanings For The

    Sets the coil constant (also referred to as the field-to-current ratio) per the selected field units. The coil constant must be set to a non-zero, positive value in order to command or query the Model 420 in units of field. ‡...
  • Page 102 Returns the persistent switch heating time in seconds. ‡ CONFigure:QUench:DETect {0|1} Sending “0” disables the automatic quench detection function of the Model 420. “1” enables the automatic quench detection function of the Model 420. See page 61 for more information. “1” is the default value. ‡ QUench:DETect? Returns “0”...

  • Page 103: Ramp Configuration Commands And Queries

    CONFigure:FIELD:UNITS {0|1} Sets the preferred field units. Sending “0” selects kilogauss. A “1” selects Tesla. “0” is the default value. The selected field units are applied to both the Model 420 display and the applicable remote commands. ‡ FIELD:UNITS? Returns “0” for field values displayed/specified in terms of kilogauss, or “1”...
  • Page 104 Remote Interface Reference Ramp Configuration Commands and Queries ‡ CONFigure:RAMP:RATE:CURRent <rate (A/s, A/min)> Sets the ramp rate in units of amperes/second or amperes/minute, per the selected ramp rate units. ‡ RAMP:RATE:CURRent? Returns the ramp rate setting in units of amperes/second or amperes/ minute, per the selected ramp rate units.

  • Page 105: Ramping State Commands And Queries

    Returns the magnet voltage in volts. Requires voltage taps to be installed across the magnet terminals. ‡ VOLTage:SUPPly? Returns the power supply voltage commanded by the Model 420 in volts. ‡ CURRent:MAGnet? Returns the measured magnet (shunt) current in amperes.

  • Page 106: Switch Heater Commands And Queries

    Remote Interface Reference Switch Heater Commands and Queries ‡ ZERO Places the Model 420 in ZEROING CURRENT mode. Ramping automatically initiates and continues at the ramp rate until the power supply output current is equal to 0 A. ‡ STATE?

  • Page 107: Quench State Control And Queries

    Quench State Control and Queries 4.5.7 Quench State Control and Queries The QUench commands control and query the quench state of the Model 420. For further information regarding the quench detection functions, see paragraph 3.5 on page 61. ‡ QUench {0|1} Clears or sets the quenched state.

  • Page 108: Trigger Functions

    4.5.8.1 Description of the Trigger Functions The Model 420 defines a trigger enable register, very similar to the enable registers of the status system, which controls which data is output and the interface to which the data is presented.
  • Page 109 Remote Interface Reference Trigger Functions Note Since trigger data is output immediately to the serial interface, it is possible to use the trigger functions to drive a terminal, modem, or a line printer (if a serial-to-parallel converter is available) connected to the serial interface.

  • Page 110: Error Messages

    Error Messages 4.6 Error Messages If an error occurs, the Model 420 will beep, load the internal error buffer with the error code and description, and set the appropriate bits in the standard event and status byte registers if enabled by the user. Error codes are returned with a negative 3 digit integer, then a comma, and then a description enclosed in double quotes.

  • Page 111: Query Errors

    At least one of the parameter values received was out of the valid range. Refer to the summary of valid ranges for the Model 420 settings on page 63. Be sure to note the field units and ramp units settings and check any unit conversions.

  • Page 112: Execution Errors

    Do not continue to use the Model 420 to operate a superconducting magnet. -402,"Serial framing error" The baud rate of the Model 420 and host device are not identical. Both the Model 420 and host device must be set to the identical baud rate. -403,"Serial parity error"...

  • Page 113: Service

    5 Service 5.1 Model 420 Maintenance The Model 420 was designed and manufactured to give years of reliable service. The only routine maintenance required is to keep the exterior surfaces of the instrument clean by gently wiping with a damp cloth moistened with a mild detergent.
  • Page 114 The Model 420 does not appear to be energized with the 32:(5 power switch in the ) position. 1. Ensure that the Model 420 is energized from a power source of proper voltage. Warning If the instrument has been found to have been connected to an incorrect power source, return the instrument to AMI for evaluation to determine the extent of the damage.
  • Page 115 Observe the same safety procedures as presented in step 2, above. 5.2.2 The Model 420 does not remember the operating setpoints after power is removed. Warning This procedure is to be performed only when the instrument is completely de-energized by removing the power-cord from the power receptacle.
  • Page 116 The power supply system will not charge the magnet. 1. Verify system interconnecting wiring. Refer to paragraph 2.5 on page 15. If the Model 420 shows “+0.00 A ↑ Status: Ramping” with the supply voltage, Vs, increasing or at the programmed voltage...
  • Page 117 4. Check the value of the voltage limit. Refer to paragraph 3.3.1.1 on page 53. Note If an energy absorber is present in the system, the Model 420 must command enough power supply voltage to overcome any forward voltage drop due to the energy absorber. Increase the voltage limits to account for the energy absorber voltage drop.
  • Page 118 DVM measurement. If the supply output voltage is approximately zero, the resistance of the power leads (not the Model 420) is dictating the maximum ramp down rate. An energy absorber is necessary to increase the rampdown rate.
  • Page 119 3. Disable the Model 420 quench detection feature (see paragraph 3.5.1 on page 62) if you suspect the Model 420 is falsely indicating a quench condition. 5.2.12 The Model 420 will not lower the field in the magnet.
  • Page 120 5. Ensure the vacuum in vacuum-jacketed dewars is of sufficiently low pressure. 5.2.14 The Model 420 will not display the magnetic field strength, only magnet current 1. Enter a coil constant in accordance with paragraph 3.2.2.2 on page 44.

  • Page 121: Additional Technical Support

    Internet e-mail at VXSSRUW#DPHULFDQPDJQHWLFVFRP . Additional technical information, latest software releases, etc. are available at the AMI World Wide Web site KWWSZZZDPHULFDQPDJQHWLFVFRP Do not return the Model 420 or other magnet system components to AMI without prior return authorization. Rev. 7...

  • Page 122: Return Authorization

    Return Authorization 5.4 Return Authorization Items to be returned to AMI for repair (warranty or otherwise) require a return authorization number to ensure your order will receive proper attention. Please call an AMI representative at (865) 482-1056 for a return authorization number before shipping any item back to the factory.

  • Page 123: Appendix

    The connectors provide an interface for connecting a single integrated instrumentation cable from the magnet support stand to the Model 420. The Model 420 can then be used to distribute the signals to the Rev. 7...

  • Page 124: Auxiliary Lhe Level/Temperature Connectors

    Auxiliary LHe Level/Temperature connectors J8A and J8B. If the Model 420 is purchased as part of a magnet system, a Magnet Station Connector instrumentation cable will be provided with the system.

  • Page 125: Current Shunt Terminals

    AMI Liquid Helium Level Instrument is connected and energized. The LHe level sensor pins are designed for use with an AMI LHe sensor and the wiring for the sensor is to have no live parts which are accessible.

  • Page 126: Program Out Bnc Connector

    The coaxial shield is the output return. The center conductor is the program out voltage. Note For maximum noise immunity, the Model 420 chassis and the chassis of any connected power supply should be tightly electrically coupled. This can be accomplished through the rack mounting or by using a grounding strap between the chassis.

  • Page 127: Quench I/O Connector

    The shell lugs of the connector are connected to the Model 420 chassis ground. J4 is a 9-pin D-sub female connector. Table A-3. Connector J4 pin definitions.

  • Page 128: Figure A-1 Example External Circuitry For Quench Input/Output

    Appendix Quench I/O Connector EXTERNAL CIRCUITRY MODEL 420 4N35 74AC04 4N35 9-PIN MALE 9-PIN FEMALE 74AC04 Figure A-1. Example external circuitry for quench input/output. Quench External Input (4N35 optocoupler input): Maximum optocoupler input LED forward voltage @ 10mA (V , across rated temperature) 1.7V...

  • Page 129: Ieee-488 Connector

    NRFD Not Ready for Data NDAC Not Data Accepted Interface Clear Service Request Attention SHIELD Cable Shield (connected to 420 chassis gnd) DIO5 Data In/Out Bit 5 DIO6 Data In/Out Bit 6 DIO7 Data In/Out Bit 7 DIO8 Data In/Out Bit 8...

  • Page 130: Rs-232/422 Connector

    DB-25 Pin DB-25 Pin Function Table A-6. PC (DB-9)-to-Model 420 connections for RS-232 operation. PC (DTE) Model 420 (DCE) DB-9 Pin DB-25 Pin Function Pin 1 of connector J12 is also connected to the Model 420 chassis ground. Rev. 7...

  • Page 131: Table A-7 Eia-530 Device-To-Model 420 Connections For Rs-422 Operation

    Appendix RS-232/422 Connector Table A-7. EIA-530 Device-to-Model 420 connections for RS-422 operation. EIA-530 Device (DTE) Model 420 (DCE) DB-25 Pin DB-25 Pin Function − − − − − − DCD+ CTS+ RTS+ − DSR+ DTR+ Rev. 7...
  • Page 132 Appendix RS-232/422 Connector Rev. 7...

  • Page 133: Index

    1 Index Index absolute limits IEEE-488 configuration AMI Internet e-mail address device clear AMI WWW address applicable hardware termination characters trigger command installation beep power rack mounting unpacking cancelling entry cleaning comm submenu keys IEEE-488 address enter serial baud rate...
  • Page 134 AMI support command conventions excessive LHe losses command handshaking no field display command reference no power quench control...

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