Keithley 2100 Service Manual

www.keithley.com

Model 2100 6 1/2-Digit Resolution Digital Multimeter

Calibration Manual

2100-905-01 Rev. A / April 2008

A G R E A T E R M E A S U R E O F C O N F I D E N C E

WARRANTY

Keithley Instruments, Inc. warrants this product to be free from defects in material and workmanship for a period of one (1) year from date of shipment.

Keithley Instruments, Inc. warrants the following items for 90 days from the date of shipment: probes, cables, software, rechargeable batteries, diskettes, and documentation.

During the warranty period, Keithley Instruments will, at its option, either repair or replace any product that proves to be defective.

To exercise this warranty, write or call your local Keithley Instruments representative, or contact

Keithley Instruments headquarters in Cleveland, Ohio. You will be given prompt assistance and return instructions. Send the product, transportation prepaid, to the indicated service facility. Repairs will be made and the product returned, transportation prepaid. Repaired or replaced products are warranted for the balance of the original warranty period, or at least 90 days.

LIMITATION OF WARRANTY

This warranty does not apply to defects resulting from product modification without Keithley Instruments’ express written consent, or misuse of any product or part. This warranty also does not apply to fuses, software, non-rechargeable batteries, damage from battery leakage, or problems arising from normal wear or failure to follow instructions.

THIS WARRANTY IS IN LIEU OF ALL OTHER WARRANTIES, EXPRESSED OR IMPLIED, INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. THE REMEDIES PROVIDED HEREIN ARE BUYER’S SOLE AND EXCLUSIVE REMEDIES.

NEITHER KEITHLEY INSTRUMENTS, INC. NOR ANY OF ITS EMPLOYEES SHALL BE LIABLE FOR ANY DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OF ITS INSTRUMENTS AND SOFTWARE, EVEN IF KEITHLEY INSTRUMENTS, INC. HAS BEEN ADVISED IN ADVANCE OF THE POSSIBILITY OF SUCH DAMAGES. SUCH EXCLUDED DAMAGES SHALL INCLUDE, BUT ARE NOT LIMITED TO: COST OF REMOVAL AND INSTALLATION, LOSSES SUSTAINED AS THE RESULT OF INJURY TO ANY PERSON, OR DAMAGE TO PROPERTY.

A G R E A T E R M E A S U R E O F C O N F I D E N C E

Keithley Instruments, Inc.

Corporate Headquarters • 28775 Aurora Road • Cleveland, Ohio 44139 440-248-0400 • Fax: [phone] • 1-888-KEITHLEY (1-888-534-8453) • www.keithley.com

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Safety Precautions

The following safety precautions should be observed before using this product and any associated instrumentation. Although some instruments and accessories would normally be used with non-hazardous voltages, there are situations where hazardous conditions may be present.

This product is intended for use by qualified personnel who recognize shock hazards and are familiar with the safety precautions required to avoid possible injury. Read and follow all installation, operation, and maintenance information carefully before using the product. Refer to the user documentation for complete product specifications.

If the product is used in a manner not specified, the protection provided by the product warranty may be impaired.

The types of product users are:

Responsible body is the individual or group responsible for the use and maintenance of equipment, for ensuring that the equipment is operated within its specifications and operating limits, and for ensuring that operators are adequately trained.

Operators use the product for its intended function. They must be trained in electrical safety procedures and proper use of the instrument. They must be protected from electric shock and contact with hazardous live circuits.

Maintenance personnel perform routine procedures on the product to keep it operating properly, for example, setting the line voltage or replacing consumable materials. Maintenance procedures are described in the user documentation. The procedures explicitly state if the operator may perform them. Otherwise, they should be performed only by service personnel.

Service personnel are trained to work on live circuits, perform safe installations, and repair products. Only properly trained service personnel may perform installation and service procedures.

Keithley Instruments products are designed for use with electrical signals that are rated Measurement Category I and Measurement Category II, as described in the International Electrotechnical Commission (IEC) Standard IEC 60664. Most measurement, control, and data I/O signals are Measurement Category I and must not be directly connected to mains voltage or to voltage sources with high transient over-voltages. Measurement Category II connections require protection for high transient over-voltages often associated with local AC mains connections. Assume all measurement, control, and data I/O connections are for connection to Category I sources unless otherwise marked or described in the user documentation.

Exercise extreme caution when a shock hazard is present. Lethal voltage may be present on cable connector jacks or test fixtures. The American National Standards Institute (ANSI) states that a shock hazard exists when voltage levels greater than 30V RMS, 42.4V peak, or 60VDC are present. A good safety practice is to expect that hazardous voltage is present in any unknown circuit before measuring.

Operators of this product must be protected from electric shock at all times. The responsible body must ensure that operators are prevented access and/or insulated from every connection point. In some cases, connections must be exposed to potential human contact. Product operators in these circumstances must be trained to protect themselves from the risk of electric shock. If the circuit is capable of operating at or above 1000V, no conductive part of the circuit may be exposed.

Do not connect switching cards directly to unlimited power circuits. They are intended to be used with impedance-limited sources. NEVER connect switching cards directly to AC mains. When connecting sources to switching cards, install protective devices to limit fault current and voltage to the card.

Before operating an instrument, ensure that the line cord is connected to a properly-grounded power receptacle. Inspect the connecting cables, test leads, and jumpers for possible wear, cracks, or breaks before each use.

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When installing equipment where access to the main power cord is restricted, such as rack mounting, a separate main input power disconnect device must be provided in close proximity to the equipment and within easy reach of the operator.

For maximum safety, do not touch the product, test cables, or any other instruments while power is applied to the circuit under test. ALWAYS remove power from the entire test system and discharge any capacitors before: connecting or disconnecting cables or jumpers, installing or removing switching cards, or making internal changes, such as installing or removing jumpers.

Do not touch any object that could provide a current path to the common side of the circuit under test or power line (earth) ground. Always make measurements with dry hands while standing on a dry, insulated surface capable of withstanding the voltage being measured.

The instrument and accessories must be used in accordance with its specifications and operating instructions, or the safety of the equipment may be impaired.

Do not exceed the maximum signal levels of the instruments and accessories, as defined in the specifications and operating information, and as shown on the instrument or test fixture panels, or switching card.

When fuses are used in a product, replace with the same type and rating for continued protection against fire hazard.

Chassis connections must only be used as shield connections for measuring circuits, NOT as safety earth ground connections.

If you are using a test fixture, keep the lid closed while power is applied to the device under test. Safe operation requires the use of a lid interlock.

If a screw is present, connect it to safety earth ground using the wire recommended in the user documentation.

The ! symbol on an instrument indicates that the user should refer to the operating instructions located in the user documentation.

The symbol on an instrument shows that it can source or measure 1000V or more, including the combined effect of normal and common mode voltages. Use standard safety precautions to avoid personal contact with these voltages.

The symbol on an instrument shows that the surface may be hot. Avoid personal contact to prevent burns.

The symbol indicates a connection terminal to the equipment frame.

If this symbol is on a product, it indicates that mercury is present in the display lamp. Please note that the lamp must be properly disposed of according to federal, state, and local laws.

The WARNING heading in the user documentation explains dangers that might result in personal injury or death. Always read the associated information very carefully before performing the indicated procedure.

The CAUTION heading in the user documentation explains hazards that could damage the instrument. Such damage may invalidate the warranty.

Instrumentation and accessories shall not be connected to humans.

Before performing any maintenance, disconnect the line cord and all test cables.

To maintain protection from electric shock and fire, replacement components in mains circuits - including the power transformer, test leads, and input jacks - must be purchased from Keithley Instruments. Standard fuses with applicable national safety approvals may be used if the rating and type are the same. Other components that are not safety-related may be purchased from other suppliers as long as they are equivalent to the original component (note that selected parts should be purchased only through Keithley Instruments to maintain accuracy and functionality of the product). If you are unsure about the applicability of a replacement component, call a Keithley Instruments office for information.

To clean an instrument, use a damp cloth or mild, water-based cleaner. Clean the exterior of the instrument only. Do not apply cleaner directly to the instrument or allow liquids to enter or spill on the instrument. Products that consist of a circuit board with no case or chassis (e.g., a data acquisition board for installation into a computer) should never require cleaning if handled according to instructions. If the board becomes contaminated and operation is affected, the board should be returned to the factory for proper cleaning/servicing.

Table of Contents

Table of Contents
Introduction...............................................................................................	2
Control Software .....................................................................................	2
Environmental conditions.....................................................................	3
Calibration considerations ...................................................................	3
Recommended test equipment ..........................................................	3
Firmware revision ...................................................................................	4
Calibration code......................................................................................	5
Zero calibration (Front/Rear)...............................................................	5
Front panel zero calibration ............................................................	5
Rear panel zero calibration .............................................................	6
Voltage function adjustment (DC and AC)......................................	6
DC voltage range adjustment.........................................................	6
AC voltage range adjustment.........................................................	9
Ohms function adjustment.................................................................	12
Resistance low range adjustment (100Ω - 1MΩ) ...................	12
Resistance high range adjustment (10MΩ - 100MΩ) ...........	16
Current function adjustment (DC and AC)....................................	18
DC current range adjustment .......................................................	18
AC current range adjustment........................................................	20
Calibration date.....................................................................................	22
Performance verification.....................................................................	22
DC voltage accuracy verification.................................................	22
AC voltage accuracy verification .................................................	23
Resistance accuracy verification.................................................	23
DC current accuracy verification .................................................	24
AC current accuracy verification..................................................	24
Frequency accuracy verification..................................................	24

Model 2100 Calibration Manual Rev. A / April 2008

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Model 2100 Calibration Manual

Introduction

This section introduces the calibration procedure for the Keithley Instruments Model 2100 6½ -Digit Resolution Digital Multimeter. This procedure should be used whenever adjustment for the following functions is necessary: AC/DC voltage, AC/DC current, and resistance. This adjustment procedure is performed by remotely sending SCPI commands over the USB interface using 2100 KI-TOOL software.

Control Software

Note	You must have one of the following items installed on the remote interface in order to
	obtain the proper VISA layer:

•Keithley Instruments I/O Layer 5.0 or greater.

•NI-VISA 3.1 or greater.

•Agilent I/O Library Suite 14.2 or greater (the I/O Layer 5.0 is included on the CD-ROM that comes with the Model 2100).

1.Install the USB device driver and KI-Tool Software from Keithley Instruments Model 2100 Product Information CD.

2.Connect the Model 2100 to the USB port and launch the KI-Tool application.

3.Verify that the correct model number is displayed in the upper right-hand corner window. See Figure 1 for details.

Test the communications link between the Keithley Instruments Model 2100 and the control software by clicking several function buttons and verifying that the DMM responds accordingly. See Figure 1 for more details.

Figure 1

2100 KI-TOOL application

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Model 2100 Calibration Manual

The adjustment procedure consists of connecting Fluke 5700A Calibrator and Fluke 5725A Amplifier (or equivalent) outputs to the Model 2100 front panel input, setting up appropriate ranges, and performing adjustment functions by sending specific SCPI commands. In the following sections, you will be provided with SCPI commands to be sent to the Model 2100. These commands should be entered into the Send String field followed by the Write button. To access command control window from 2100 KI-TOOL application, click on

Tool > Command Control.

Note	Be sure that the correct model number is selected before sending any SCPI commands.
	Figure 2 shows the drop-down selection menu for the active units connected to the PC.

Environmental conditions

Conduct the calibration procedures in a location that has:

•An ambient temperature of 5°C to 40°C.

•A relative humidity of less than 80% unless otherwise noted.

Calibration considerations

When performing the calibration procedure:

•Make sure that the equipment is properly warmed up and connected to the appropriate input jacks. Also make sure that the correct input jacks are selected with the INPUTS switch.

•Make sure the calibrator is in OPERATE before you complete each calibration step.

•Do not connect test equipment to the Model 2100 through a scanner or other switching equipment.

•If an error occurs during calibration, the Model 2100 will generate an appropriate error message. Please refer to Model 2100 User’s Manual for error code descriptions.

•During the adjustment process the Model 2100 may not display the correct amplitude of the applied signal. This condition is normal.

•After the adjustment procedure is completed, perform Section 3 (Performance Verification) to verify that the Model 2100 is operating within the manufacturer’s specifications.

Recommended test equipment

Use a Fluke Model 5700A Calibrator and 5725A Amplifier (or the equivalent) to perform the Model 2100 multimeter adjustments.

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Model 2100 Calibration Manual

Firmware revision

If your Model 2100 has firmware versions 1.03 or 1.04, the firmware must be updated to the latest version before this procedure can be performed. You may identify the firmware version as follows:

1. Press the QUERY button and enter the following SCPI command:

*IDN?

2.Figure 2 shows the typical location of the firmware version number. If the firmware requires updating, refer to www.keithley.com for detailed instructions.

Figure 2

Command Control Window

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Model 2100 Calibration Manual

Calibration code

Unlock the calibration routine by entering the following calibration code procedure: 1. Unlock the calibration function by sending the SCPI command:

CAL:PROT:CODE <up to 8-character string>

The default code command is:

CAL:PROT:CODE p8125652

2. Initiate the calibration routine by sending the SCPI command:

CAL:PROT:INIT

Zero calibration (front/rear)

Front panel zero calibration

1.Connect low thermal, 4-wire short (Keithley Instruments Model 8610 or equivalent) to the instrument front panel input terminals.

2.Set INPUTS select switch to front terminals. Allow connections to stabilize for a minimum of five minutes before proceeding.

Note	Be sure to connect the low-thermal short properly to the HI, LO, and SENSE terminals.
	Keep drafts away from low-thermal connections to avoid thermal drift, which could affect
	calibration accuracy.
3.	Initiate the Model 2100 zero calibration by sending the following SCPI command:
	CAL:PROT:DC:STEP 3,0
4.	Wait until the following message is displayed on the Model 2100 display:
	Cali OK

Model 2100 Calibration Manual Rev. A / April 2008

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