Agilent Technologies manual N6700 Modular Power System Scope

Page 28

2 Installation

Protecting Sensitive Loads from AC Power Switching Transients

This only applies if you are connecting loads that are highly sensitive to voltage

NOTE or current transients to the output of the modular power system. If your load is connected directly to the output of the power system and is not connected to chassis ground in any way, you do not need to worry about AC power switching transients appearing at the output of the modular power system.

Operating the AC line switch can inject common mode current spikes into the DC output leads, resulting in voltage spikes, which may damage sensitive loads. Note that any electronic device meeting international standards for EMI compliance is likely to generate similar current spikes. This situation arises from the presence of EMI filters at both the AC input and the DC output of the modular power system. These filters typically include common mode capacitors connected to the power system chassis. Since the AC input has an earth ground, any load that is also earth-grounded provides a possible return path for common mode currents.

The following figure illustrates a typical situation where a load that might otherwise be floating becomes grounded, thereby providing a return path for any injected currents. In this case, the return path is created by the low side of the scope probe, which is connected to the load circuit common and also to the scope’s chassis. For this and similar cases, the following steps by order of preference, will help mitigate common mode current spikes appearing at the output when the modular power system is turned on or off by the AC line switch:

1Install the ferrite core on the power cord as described under "Snap-On Core". This inserts impedance in the current path.

2Install a separate “bonding” wire from the load’s common point, to the ground terminal of the modular power system. This provides a lower impedance path that helps direct injected currents away from the DC output leads (and the sensitive load).

3Break the return path through the external equipment. For example, instead of the single-ended scope shown in the figure, you can use a differential scope with a floating input or you can connect an isolated measuring instrument to the load.

1

N6700 Modular

Power System

-S

+

+S

2

+

Scope

probe

3

NOTE

Disconnecting the load from the output before switching the modular power system on or off will always protect the load from common mode currents.

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Series N6700 User’s Guide

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Contents Agilent Technologies Low-Profile Modular Power System Legal Notices Agilent Technologies, IncSafety Notices GeneralThis Book Contents Agilent Models N6751A/N6752A, N6753A/N6754A, N6761A/N6762A 100103 104Essential operating features of the power system Modular Power System MPSReferred to as MPS and power system throughout this manual Agilent N6700 Modular Power System At a Glance Output FeaturesSystem Features Model DifferencesFront Panel At a Glance Rear Panel At a GlanceIndicators Front Panel Display At a GlanceSingle-channel view Interface statusOperating status Front Panel Keys At a GlanceNumber keys Front Panel Menu Reference OCPUSB Subsystem Commands Scpi Command SummaryScpi Command Description Scpi Command FUNCtion VOLTage CURRent, @chanlist SWEepALL Common Commands RST SettingsCommand Description These settings are set by the *RST Reset commandInstallation General Information ModelsItems Supplied OptionsInstalling the Unit Safety ConsiderationsRack Installation Inspecting the UnitInstallation Bench Installation CleaningChannel Number Hz OperationConnecting the Line Cord InstallationPower cord, resulting in fire Snap-On Ferrite CoreConnecting the Outputs Screws securely tightenedTerminals. Sense jumpers are provided for local sensing Terminals in any other wayWire Size AWGResponse Time with an External Capacitor Multiple LoadsPositive and Negative Voltages N6700 Modular Power System Scope Remote Sense Connections Drop in the sense leads can degrade the voltage regulationParallel Connections Open Sense LeadsOver-voltage Protection Considerations Output Noise ConsiderationsWhen programming via the front panel or using Scpi commands Grouping the OutputsFirmware revision B.00.00 and up Discussed in under System-Related OperationsEffect on Specifications Recovery TimeSeries Connections Terminal may be more than 240 VDC from chassis groundSetting the Outputs Desired operating voltageEffect on Specifications Getting Started Menu structure is found in ChapterEntering an Output Voltage Setting Turning the Unit OnSelecting an Output Channel Method 1 Use the Navigation and Arrow KeysEntering a Current Limit Setting Use the On/Off key to enable the outputEnabling the Output Method 2 Use the Current key to enter a valueUsing the Front Panel Menu Press the Menu key to access the front panel command menuSet the Over-Voltage Protection MenuExiting the Command Menu Meter Back There are two ways to exit the command menuCase of Trouble Enter ChannelConnecting to the Interfaces Cause the unit to reset and require operator interventionGpib Interface Automation-Ready CD that is shipped with your productUSB-enabled instrument to the Universal Serial Bus USB. USB InterfaceLAN Interface Following figure illustrates a typical USB interface systemConnecting to a Site LAN Connecting to a Private LANRelease the previous settings Factory-shipped instrument LAN settings are configured toDhcp server. You can leave these settings as they are. Most Will come on when the LAN port has been configuredViewing the Currently Active LAN Settings Configuring the LAN ParametersLAN Parameters Take effectName DomainReset LAN CommunicationUsing the Web Server ReducedUsing Sockets Using TelnetTelnet connections to be made Restoring the Non-volatile Factory Settings Enable/Disable the USB, LAN, and Web ServerSecuring the Interfaces Factory-shipped non-volatile LAN settings Other factory-shipped non-volatile settingsOperating the Power System Programming the Output Select an Output ChannelSet the Output Voltage Set the Voltage Slew RateEnable the Output Set the Output CurrentSequence Multiple Outputs Outpdelrise .1,@2Front Panel Scpi Command Select Output\Polarity Program the Output RelaysOutp Outprelpol REV,@1Enable the Output to Respond to Trigger Commands Front Panel Scpi Command Select Transient\ModeFront Panel Scpi Command Select Transient\Step Synchronizing Output StepsSelect the Transient Trigger Source Initiate the Transient Trigger SystemGenerate Trigger Out Signals Front Panel Scpi Command Select Transient\ControlTrigger the Output Scroll to and select AbortSimultaneous Voltage and Current Measurements Making MeasurementsMeasurement Ranges Using the Protection Functions Front Panel Scpi Command Select Protect\OVPSet the Over-Current Protection Enter a value in the OVP level box To 10 Press SelectCouple Output Protection Clear Output Protection FunctionsSystem-Related Operations Self-TestInstrument Identification Instrument State StorageFront Panel Scpi Command Select System\Groups Output GroupsSystgrodelall SystrebFront Panel Scpi Command Select System\Preferences\Lock Front Panel Scpi Command Select System\Preferences\KeysFront Panel Keys LockoutFront Panel Display Screen SaverContrast ViewWhen the power system is turned off Programming High-Speed Test ExtensionsList Function All models Refer to , Model DifferencesFront Panel Scpi Command Select Transient\List\Config Front Panel Scpi Command Select Transient\List\PaceProgram an Output Pulse or Pulse Train Voltmode LIST, @1Front Panel Scpi Command Select Transient\List\Repeat Front Panel Scpi Command Select Transient\TrigSourceTrigtransour BUS, @1 Inittran @1Program an Arbitrary List Select the List Step numberFront Panel Scpi Command Select the Transient\List\Repeat Liststep AUTO, @1Adjust the Measurement Sample Rate Front Panel Scpi Command Select Measure\SweepDigitizer Function Programming the DigitizerAcquisition trigger, use Specify a Window FunctionTo offset the measurement on Front Panel Scpi Command Select Measure\Window Front Panel Scpi Command Not AvailableSynchronizing Digitizer Measurements Retrieve Measurement Array DataSelect the Measurement Trigger Source Sensfunc VOLT,@14Sensfunc CURR,@14 TransientnFront Panel Scpi Command Select Measure\Control Initiate the Measurement Trigger SystemTrigger the Measurement Trigacq @1Appendix a Specifications Performance Specifications Agilent Models N6751A/N6752A, N6753A/N6754A, N6761A/N6762ASupplemental Characteristics Up-programming Time with full resistive load Up-programming Settling Time with full resistive loadDown-programming Settling Time with no load Down-programming Time with Capacitive loadAutoranging Characteristic Output Impedance GraphsModel N6753A, CV Mode, @20V, 15A 0125 Magnitude Load Transient Recovery Time Agilent Models N6731B N6736B and N6741B N6746BCommon Mode Noise Temperature Coefficient per CFrom 20 Hz 20 MHz from either output to chassis Agilent Models N6773A N6776A 20 mA Agilent N6700B, N6701A, N6702A MPS Mainframes Dimensions Net WeightEnvironmental Conditions AC InputOutline Diagram 432.5 mm 17.03 482.6 mm 19.00 425.45 mmAppendix B Using the Digital Port Digital Control Port Configuring the Digital Control Port Bi-directional Digital I/OPin Bit Select System\IO\DigPort\PinnDigital Input Front Panel Scpi Command Select System\IO\DigPort\PinnExternal Trigger Fault Output Front Panel Scpi Command Select System\IO\DigPort\Pin1Front Panel Scpi Command Select System\IO\DigPort\Pin3 Inhibit InputClearing a System Protection Fault Fault/Inhibit System ProtectionMainframes This chapter discusses the power allocation function For the majority of Agilent N6700 Modular Power SystemPower rating of Agilent N6700 mainframes is as follows Rating of the mainframePower Limit Operation Mainframe Power LimitModule Power Limit Must reset the power limit to its maximum rated valueTo set a power limit on output Module Power AllocationPower limit function will not activate Page Appendix D Output On/Off Synchronization Power Modules Options and Mode Minimum Synchronizing Output Turn-on DelaysTutorial Procedure Enable the Synchronization FunctionOutpcoup on Outpcoup OFFSpecify the Common Delay Offset Specify the Turn-On Delays for each Output ChannelSpecify which Output Channels will be Synchronized Digital Connections and Configuration Synchronizing Multiple MainframesOperation System\IO\DigPort\Pin6DIGPIN6FUNC ONC DIGPIN7FUNC OffcIndex Inhibit input Instrument11, 42 ListRemote interface SpecificationsSystem protection Declaration of Conformity Manual Updates