Keithley 2002 User Manual

Front Panel Operation
2-71
The equation used to calculate the mean is:
where: x
i
is a stored reading, and
n is the number of stored readings.
Note: If n = 0, the result is NAN (not a number).
4. SDEV  This operation displays the standard deviation
of the stored readings, for example:
SDEV=1.4944e-03
The equation used to calculate the standard deviation is:
where: x
i
is a stored reading, and
n is the number of stored readings.
Note: If n ≤ 1, the result is NAN (not a number).
NOTE
These statistics are invalid if the measure-
ment function changed during data store
(e.g., when scanning different functions).
The Model 2002 uses IEEE-754 floating
point format for math calculations.
The last display in this series allows you to dump the buff-
ered readings to a printer. See paragraph 2.12.2 for details on
configuring printers.
2.9 Filter
Filtering stabilizes noisy measurements. The Model 2002
uses a digital filter, which is based on reading conversions.
The displayed, stored, or transmitted reading is simply an av-
erage of a number of reading conversions.
When a filter is enabled, the selected filter configuration for
that measurement function is in effect. Filtering is enabled
by pressing the FILTER key (FILT annunciator turns on).
Pressing FILTER a second time disables the filter.
Filtering is performed only on primary display measure-
ments; it has no effect on multiple displays.
2.9.1 Filter types
The Model 2002 has two types of digital filters: averaging
and advanced. Both types are a simple average of one to 100
reading conversions. The difference between them is the
user-programmable noise “window” of the advanced filter.
The noise window, which is expressed as a percentage of
range (0-100%), allows a faster response time to large signal
step changes (e.g., scanned readings). A reading conversion
outside the plus or minus noise window fills the filter “stack”
immediately.
If the noise does not exceed the selected percentage of range,
the reading is based on an average of reading conversions. In
this case, the advanced filter works the same as the averaging
filter. If the noise does exceed the selected percentage, the
reading is a single reading conversion, and new averaging
starts from this point. The two filter types are compared in
Figure 2-30.
2.9.2 Filter modes
An additional filter parameter is the mode, either moving or
repeating. A moving filter is a first-in, first-out stack, where
the newest reading conversion replaces the oldest. An aver-
age of the stacked reading conversions yields a reading.
Therefore, after a selected number of conversions, a moving
filter gives a new reading for every new conversion.
A repeating filter takes a selected number of reading conver-
sions, averages them, and yields a reading. It then flushes its
stack and starts over. This characteristic is useful when scan-
ning channels.
If burst mode is enabled with filtering, the post-processing
time increases. A filter mode setting of repeating is ignored
in burst mode.
Filter modes are compared in Figure 2-31.
y
X
i
i1=
n
∑
n
---------------=
X
i
2
-
1
n
---
X
i
i=1
n
∑






2



i=1
n
∑
n-1
-----------------------------------------------
y =

Keithley 2002 Specifications

General

Resolution	8.5 digits
DC Voltage Accuracy	±0.0006%
Maximum DC Voltage	1000 V
Maximum AC Voltage	750 V
Maximum DC Current	3 A
Maximum AC Current	3 A
Connectivity	GPIB, RS-232
DC Voltage Range	100 mV to 1000 V
AC Voltage Range	100 mV to 750 V
Resistance Range	10 Ω to 1 GΩ
Model	2002
Category	Multimeter
Interface	GPIB, RS-232
AC Current Accuracy	±0.1%
Frequency Range	0.1Hz to 300kHz
Display	VFD
Type	Digital
Power Supply	100-240V AC, 50/60Hz
Current Range (DC)	100 μA to 3 A
Current Accuracy (DC)	±0.01%
Current Range (AC)	100 μA to 3 A
Current Accuracy (AC)	±0.1%
DC Current Range	100 μA to 3 A
AC Current Range	100 μA to 3 A

Summary

Safety Precautions

General Information

Introduction

Provides an overview of the Model 2002 multimeter and its manual structure.

Features

Highlights key capabilities of the Model 2002, including measurement functions and display.

Warranty Information

Details warranty service procedures and contact information.

Manual Addenda

Explains how changes to the manual will be communicated.

Safety Symbols and Terms

Defines safety symbols and terms used in the manual and on the instrument.

Specifications

Refers to Appendix A for detailed product specifications.

Inspection

Instructions for inspecting the instrument after unpacking.

Options and Accessories

Lists available options and accessories for the Model 2002.

Front Panel Operation

Introduction

Outlines the sections covered in the front panel operation chapter.

Power-up

Information on connecting to line power, warm-up, and power-up sequence.

Display

Covers display formats, messages, and multiple display features.

Functions

Describes the measurement functions of the instrument (DCV, ACV, DCI, ACI, Ohms, Freq, Temp).

Range

Explains how range selection affects resolution, accuracy, and maximum signal.

Relative

Details on using the relative feature to null offsets or subtract baseline values.

Triggers

Discusses front panel triggering, configuration, and external triggering.

Buffer

Covers buffer use, data storage, and recalling data, time stamp, and statistics.

Filter

Explains the use of digital filter types to reduce reading noise.

Math

Describes calculations that can be performed on readings in continuous operation.

Scanning

Discusses setting up internal and external scans, ratio, and delta calculations.

Menu

Covers selections controlled from the main menu, including setup, GPIB, calibration, and tests.

IEEE-488 Reference

Introduction

Provides reference information on programming the Model 2002 over the IEEE-488 bus.

IEEE-488 bus connections

Explains instrument connections to the IEEE-488 bus.

Primary address selection

Explains how to set the primary address from the front panel.

QuickBASIC 4.5 programming

Summarizes programming using QuickBASIC 4.5 with the IEEE interface.

General bus commands

Covers general IEEE-488 commands for basic operations like placing the unit in remote.

Front panel aspects of IEEE-488 operation

Covers status indicators, messages, and LOCAL key use for IEEE-488 operation.

Status structure

Explains the various registers and queues that make up the status structure.

Trigger model

Explains the operation process (Trigger Model) over the IEEE-488 bus.

Program message syntax

Covers the syntax rules for common commands and SCPI commands.

Common commands

Covers the IEEE-488.2 common commands used by the Model 2002.

SCPI Signal Oriented Measurement Commands

Covers the signal oriented commands used by the Model 2002.

Calculate subsystems

Covers math operations: CALCulate1 (math), CALCulate2 (buffer), CALCulate3 (limits).

:DISPlay subsystem

Controls the display of readings and messages on the Model 2002.

:FORMat subsystem

Selects the data format for transferring instrument readings over the bus.

:INPut subsystem

Controls the Model 1801 Nanovolt Preamp.

:OUTPut subsystem

Sets the polarity for the digital output port.

:ROUTe subsystem

Configures and controls switching.

Sense subsystems

Configures measurement functions (Sense 1) and reads digital input (Sense 2).

:SOURce subsystem

Sets the logic level (true or false) of each digital output line.

:STATus subsystem

Controls the status registers.

:SYSTem subsystem

Contains miscellaneous commands not covered by other subsystems.

:TRACe subsystem

Configures and controls data storage into the buffer.

Trigger subsystem

Configures the three layers of the Trigger Model.

:UNIT subsystem

Configures and controls measurement units for TEMP and ACV.

Specifications

DCV Input Characteristics and Accuracy

Provides DCV input characteristics and accuracy specifications.

AC Volts

Specifications for ACV measurements, including RMS, average, peak, and crest factor.

AC Amps

Specifications for ACI and DCI measurements.

Two-Wire and Four-Wire Ohms

Specifications for resistance measurements.

DC In-Circuit Current

Specifications for the DC in-circuit current measurement function.

HP3458A Emulation Mode

Introduction

Provides information on using the Model 2002 HP3458A emulation mode for compatibility.

Firmware revision level

Details how to display the firmware revision level.

Enabling the HP3458A emulation mode

Step-by-step guide to enable HP3458A emulation mode via the GPIB menu.

Unsupported commands

Lists commands not supported by the Model 2002 HP3458A emulation mode.

Command syntax and compatibility

Discusses command syntax and compatibility issues for HP3458A emulation.

Parameter defaults

Explains default parameters assumed when omitted, and unsupported syntax.

Delimiting parameters

Describes the use of spaces or commas for parameter separation.

Function command short forms

Lists short forms for common FUNC commands.

Unsupported queries

Describes behavior for unsupported query commands.

Error checking

Details commands for emulation mode error checking.

Supported HP3458A commands

Summarizes supported commands with descriptions.

APER

Programs the A/D integration time.

ARANGE

Enables or disables the autorange mode.

AZERO

Enables or disables the autozero mode.

CALSTR?

Requests the calibration date.

CSB

Clears status register bits.

DELAY

Programs the time interval between trigger and sample events.

DISP

Enables/disables display, clears display, sends message to display.

EMASK

Enables certain error conditions to set the error bit in the status register.

ERR?

Requests the error register value.

ERRSTR?

Requests the error number and error response string.

FREQ

Selects the frequency measurement function.

FSOURCE

Selects the signal type for frequency or period measurements.

FUNC

Selects the measurement function and range.

ID?

Requests the instrument's identification string.

LINE?

Requests the AC power line frequency.

MCOUNT?

Requests the number of readings presently stored in memory.

MEM

Enables/disables reading memory and designates storage mode.

MFORMAT

Clears reading memory and designates storage format for new readings.

MSIZE?

Requests reading memory size.

NDIG

Programs the number of display digits used for readings.

NPLC

Programs the A/D converter integration time in power line cycles.

NRDGS

Programs the number of readings per trigger and the trigger event.

OCOMP

Enables or disables the offset-compensated ohms mode.

OFORMAT

Programs the data format for both normal and memory readings.

OPT?

Requests a report of installed options.

PER

Selects the period measurement function.

PRESET

Selects one of two preset instrument configurations.

RANGE

Selects the measurement range.

RESET

Resets the Model 2002 to the power-on state.

REV?

Requests the main and front panel revision levels.

RMEM?

Requests readings stored in memory.

RQS

Enables or disables status register bits that can cause an SRQ.

RSTATE

Recalls an instrument configuration from memory.

SETACV

Selects the RMS conversion technique for AC and AC+DC measurements.

SRQ

Enables SRQ.

SSTATE

Stores the instrument's present configuration in memory.

STB?

Requests the status register value.

SWEEP

Programs the interval between readings and number of samples per trigger.

T or TRIG

Programs the trigger event.

TARM

Specifies the event that arms the trigger event.

TEMP?

Requests the internal temperature of the Model 2002.

TERM

Requests INPUTS switch status.

TIMER

Defines the timer sample interval.