Keithley Instruments
DMM6500 in a Keysight 34401A Application
28775 Aurora Road
Cleveland, Ohio 44139
1-800-935-5595
tek.com/keithley
Emulation and Migration Guide
Introduction
Thank you for choosing a Keithley Instruments product. This document provides information about using the
DMM6500 as a drop-in replacement in a Keysight 34401A test system application, and also provides a guide to
migrating from a Keysight 34401A to a DMM6500 in native mode.
The DMM6500 provides greater functionality and improved accuracy over the Keysight 34401A. However,
established customer test systems can be sustained after replacement without significant reconfiguration and
code changes by using emulation mode.
Emulation mode is intended primarily for remote command operation. You can use the DMM6500 SCPI 34401
command set to emulate a Keysight 34401A, but you will not have access to the full range of features available
in its native mode. In addition, the options that you can set from the front panel are more limited than the
front-panel options on the DMM6500.
This guide describes:
How to configure the DMM6500 for emulation mode.
The hardware interface differences between the Keysight 34401A and the DMM6500.
The software differences between SCPI 34401 on the DMM6500 and the standard SCPI command set
available on the Keysight 34401A product.
Application examples that provide insight into migrating from Keysight 34401A emulation to DMM650
s
tandard SCPI commands.
0
Comparison of key features
Although new functions and features are supported in native mode, the emulation mode will restrict you to
legacy instrument features. The DMM6500 standard SCPI command set lets you access new measurement
functions, ranges, and data analysis tools. See Updating your code to use DMM6500 SCPI commands (on
page 9) for more information.
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The following table is a comparison of key features between the instruments.
DMM6500 Keysight 34401A
Resolution
DMM input terminals
Plug-in module slots and channels
Module cards supported
Reading capacity
Non-volatile memory
Basic DCV accuracy
Measurements
DCV, ACV (ranges)
DCI (ranges)
ACI (ranges)
Temperature
Diode
Capacitance
Digitizer
6 ½ digits 6 ½ digits
Front and rear Front and rear
Single slot, up to 10
independent channels
2000-SCAN, 2001-TCSCAN N/A
7M 512
No Yes
25 ppm / 1 year; 30 ppm / 2 year 35 ppm / 1 year
Same
10 μA, 100 μA, 1 mA,
10 mA, 100 mA, 1 A, 3 A, 10 A
100 μA, 1 mA,
10 mA, 100 mA, 1 A, 3 A, 10 A
Thermocouple, RTD, thermistor N/A
10 V clamp (10 μA,
100 μA, 1 mA, and 10 mA test
currents)
1 nF, 10 nF, 100 nF,
1 μF, 10 μF, 100 μF
Up to 1 MS/s voltage or current N/A
N/A
10 mA, 100 mA, 1 A, 3 A
1 A, 3 A
1 V clamp (1 mA)
N/A
Resistance (lowest ranges)
PC interfaces
USB flash drive support
Mechanical size
(for rack mounting)
Measurement accuracy and
resolution
1 Ω, 10 Ω, 100 Ω 100 Ω
USB/LAN-LXI (standard)
GPIB/RS-232/TSP-Link
(optional)
Yes No
2U, ½ rack
14.039 in. (356.6 mm) deep 13.713 in. (348.3 mm) deep
The datasheet for each model provides specifications. See the Keithley
Instruments website.
GPIB/RS-232 (standard)
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Select the SCPI command set for emulation mode
To use the DMM6500 as a drop-in replacement in an existing Keysight 34401A application, you must use the
SCPI 34401 command set. This command set includes most of the commands that are available in the
Keysight 34401A product.
You can select the SCPI 34401 command set from the front panel or over the remote interface.
When you change to the SCPI 34401 command set, you must reboot the instrument. You will be prompted by
the front panel to reboot, but you will not be prompted if using remote commands.
Using the front panel:
1. Press the MENU key.
2. Under System, select Settings.
3. Select the button next to Command Set.
4. Select SCPI 34401. You will be prompted to reboot.
5. Select OK.
Using SCPI or TSP remote commands:
Send the command:
*lang SCPI34401
Reboot the instrument.
Identify the DMM6500 when using the SCPI 34401 command set
To ensure a level of compatibility in querying for the identification string of the instrument, when set to use the
SCPI 34401 command set, the DMM6500 will return the following text string:
KEITHLEY INSTRUMENTS INC.,34401A,<serial_number>,<firmware_version>
The manufacturer will always be set to "Keithley Instruments Inc.", and is not configurable to report the
manufacturer as "Keysight", "Agilent", or "Hewlett-Packard".
Front-panel operation with the SCPI 34401 command set
When the SCPI 34401 command set is selected, the options available through the front panel are limited.
Emulation mode is intended primarily for remote command operation.
The following topics describe the options that are available when the SCPI 34401 command set is selected.
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DMM6500 in a Keysight 34401A Application Emulation and Migration Guide
Home screen display
When the SCPI 34401 command set is selected, you can select the User, Channel, and Functions swipe
screens.
The options available on the Home screen are described here.
Figure 1: Home screen when the SCPI 34401 command set is selected
# Screen element Description
System status
1
and event
indicators
Located at the top of the Home screen. These indicators provide information
about the present state of the instrument. Some of the indicators open up a
dialog box with more information or a settings menu when selected.
MEASURE view
2
area
Swipe screen
3
area
Green part of the Home screen; displays the value of the present
measurement.
Blue part of the Home screen. It displays the User and Functions options. If the
rear terminals are selected, Channel options are available.
Status and error indicators when the SCPI 34401 command set is selected
The indicators at the top of the Home screen contain information about instrument settings and states. Some of
the indicators also provide access to instrument settings.
Figure 2: Status and error indicators — SCPI 34401
The communications indicator is at the left. The options you might see here include:
Indicator Meaning
Local
GPIB
RS-232
TCPIP
VXI-11
USBTMC
Telnet
Instrument is controlled from the front panel.
Instrument is communicating through a GPIB
interface.
Instrument is communicating through an RS-232
interface.
Instrument is communicating through a LAN
interface.
Instrument is communicating using VXI-11.
Instrument is communicating through a USB
interface.
Instrument is communicating through Telnet.
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T
he communications indicator displays the type of communications the instrument is using. Select the indicator
to display the present communications settings. Select Change Settings at the bottom of the dialog box to
open the System Communications screen, where you can change the settings.
There is an activity indicator next to the communications indicator. When the instrument is communicating with
a remote interface, the up and down arrows flash.
If a service request has been generated, SRQ is displayed to the right of the up and down arrows. When this
indicator is on, a service request has been generated. This indicator stays on until the serial poll byte is read or
all the conditions that caused SRQ are cleared.
The system event indicator is on the far right side of the instrument status indicator bar. This indicator changes
based on the type of event that occurred.
Press the indicator to open a message screen with a brief description of the error, warning, or event. Press the
Event Log button to see the System Events screen, which contains more detailed descriptions of the events
and options for controlling the types of error events that are displayed on the front panel.
The following table describes the different event indicators and what they mean.
Icon Description
An empty triangle means that no new events were logged in the event log since the last time you
viewed the event log.
A blue circle means that an informational event message was logged. The message is for information
only. This indicates status changes or information that may be helpful. If the Log Command option is
on, it also includes commands.
A yellow triangle means that a warning event message was logged. This message indicates that a
change occurred that could affect operation.
A red triangle means that an error event message was logged. This may indicate that a command
was sent incorrectly.
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DMM6500 in a Keysight 34401A Application Emulation and Migration Guide
Event messages
During operation and programming, front-panel messages may be displayed. Messages are information,
warning, or error notifications.
Figure 3: Example front-panel error message
Menus when the SCPI 34401 command set is selected
When the SCPI 34401 command set is selected, the only menu available from the front panel is the System
Settings menu.
System Settings menu when the SCPI 34401 command set is selected
The System Settings menu is available when the SCPI 34401 command set is selected. The options are the
same as the options when the other command sets are selected, except that the TSP-Link options in the
Communication menu are not available.
Figure 4: Main menu when the SCPI 34401 command set is selected
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Keysight 34401A to DMM6500 hardware interface differences
The following topics detail the differences between the hardware connections used for the Keysight 34401A
and the interfaces provided for the DMM6500.
Remote interfaces
The Keysight 34401A was supplied with both GPIB and RS-232 as standard interfaces. The DMM6500 is
supplied with USB and Ethernet as standard interfaces. The instrument also supports GPIB and RS-232 with
optional communication accessory modules.
The following communication accessory modules are available for the DMM6500. These modules are designed
for user installation, and do not require the DMM6500 to be shipped to Keithley Instruments for service or
adjustment.
KTTI-GPIB – Communication and Digital I/O Accessory
KTTI-RS232 – Communication and Digital I/O Accessory
For more information about the communication accessory cards (such as configuration through the front panel
and over the remote interface), visit tek.com/keithley (http://www.tek.com/keithley
).
Trigger Link and external trigger and voltmeter support
The Keysight 34401A provides two BNC connectors on the rear panel for sending and receiving trigger pulses.
The voltmeter complete output and external trigger input signals are supported by the VM COMP and EXT
TRIG connectors,
The DMM6500 also supports the external trigger input and voltmeter complete signals. See the next figure.
Figure 5: DMM6500 external trigger connections
When using the SCPI 34401 command set, the DMM6500 trigger signal for voltmeter complete output is sent to
the EXTERNAL TRIGGER OUT connector. External trigger input signals are received through the EXTERNAL
TRIGGER IN connector.
Keysight 34401A to DMM6500 software differences
You can use existing code from a Keysight 34401A application with a DMM6500. Apart from the exceptions
noted in this section, Keysight 34401A emulation for the DMM6500 supports all SCPI commands that are
supported by the 34401A.
Details about these differences and other commands that operate differently are described in the following
sections.
If a command is not listed in this section, you can use the command in the same way that you did for the
Keysight 34401A. See the original Keysight 34401A documentation for details.
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SCPI 34401 overview and general exceptions
When you apply the SCPI 34401 command and set, the DMM6500 operation matches Keysight 34401A
operation. Commands run as described and have the same defaults as listed in the original Keysight 34401A
User Manual. However, the following exceptions may affect your test system performance:
Commands run faster than on the Keysight 34401A.
Measurements are acquired at the same speed or faster than on a Keysight 34401A.
Error numbers generated in emulation mode (using the SCPI 34401 command set) may not match t
iginal product.
or
The following items are additional general exceptions when you select the SCPI 34401 command set.
Item Exception
Auto delay The auto delay times are derived from hardware design and therefore may not be the
same as on the Keysight 34401A. Querying the auto delay duration is not supported,
and will return zero seconds.
Bandwidth The DMM6500 will use a bandwidth of 30 Hz when the 20 Hz bandwidth is selected,
and will use a bandwidth of 300 Hz when the 200 Hz bandwidth is selected.
Calibration Not supported.
Continuity The continuity tone is disabled when the beeper is turned off.
Display text data When selected, this will appear on the User swipe screen of the Home screen.
Emulation of other
instruments
Frequency and period
aperture
Frequency and period
threshold range
Front panel defaults The DMM6500 does not support front panel defaults that differ from remote bus
Limits The beeper is not supported for limit testing. Limit annunciators (indicators on the
MIN/MAX/DEF Commands that accept the MIN or MAX parameter will also accept the DEF
Nonvolatile storage Settings are not stored when you turn off the DMM6500. The instrument reverts to
Ratio measurements The voltage on the SENSE terminals is limited to 10 V when making
While the Keysight 34401A can emulate other instruments, this functionality is not
supported on the DMM6500 in SCPI 34401 mode.
The DMM6500 will accept values up to 1 s, but will use only up to 250 ms. The
Keysight 34401A allows an aperture of up to 1 s.
The Keysight 34401A maximum range value is 1000 V. The DMM6500 maximum is
700 V.
command defaults.
front panel display) are not implemented.
parameter.
defaults when the instrument is turned on.
VOLTage:DC:RATio measurements.
he
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*PSC
:L3
SYSTem:RWLock
SCPI 34401 command set exceptions
The following are command set exceptions for the Keysight SCPI 34401 command set when used on the
DMM6500.
Keysight 34401A command Exceptions
Not supported.
*TST?
[:SENSe[1]]:FREQuency:APERture
[:SENSe[1]]:FREQuency:VOLTage:RANGe <n>
[:SENSe[1]]:PERiod:APERture
[:SENSe[1]]:PERiod:VOLTage:RANGe <n>
[:SENSe[1]]:VOLTage:AC: RANGe <n>
DISPlay:TEXT <a>
:L2
Not supported. This command will return 0
(passed).
If this command generates an error, the error is
logged twice.
The maximum range is 700 V. Accepts higher
values, but the range will be set to 700 V. The set
value is accepted and stored for later query.
If this command generates an error, the error is
logged twice.
The maximum range is 700 V. Accepts higher
values, but the range will be set to 700 V. The set
value is accepted and stored for later query.
The maximum range is 700 V. Accepts higher
values, but the range will be set to 700 V. The set
value is accepted and stored for later query. The
Keysight 34401A product maximum is ± 1000 V.
When enabled, text will appear on line 1 of the
user swipe screen.
Not supported.
Not supported.
Updating your code to use DMM6500 SCPI commands
The DMM6500 standard SCPI command set lets you access new measurement functions, ranges, and data
analysis tools. However, these new features are not available when using the SCPI 34401A command set, and
you cannot run more than one command set at once.
To access these new features, you can modify your existing SCPI code to use the DMM6500 standard mode
SCPI commands. The examples in this section detail the code changes you can make to the SCPI 34401A
command set applications in the previous section.
You may need to make changes so that this code will run in your programming environment. In the following
command tables, the SCPI commands have a light gray background. The light green shaded code represents
pseudocode that will vary depending on the programming environment you use.
For more information on the functions and features available on the DMM6500, see the DMM6500
specification, available from tek.com/keithley (http://www.tek.com/keithley
077146700 / May 2018 9
).
DMM6500 in a Keysight 34401A Application Emulation and Migration Guide
*RST
*RST
*CLS
*CLS
MEASURE:CURRENT:DC? 1A,0.001MA
SENS:FUNC "CURR:DC"
SENS:CURR:DC:RANG 1
DISP:CURR:DC:DIG 6
SENS:CURR:DC:NPLC 1
READ?
*RST
*RST
*CLS
*CLS
CONF:VOLT:DC
SENS:FUNC "VOLT:DC"
SENS:VOLT:DC:RANG:AUTO ON
SENS:VOLT:DC:NPLC 1
DISP:VOLT:DC:DIG 6
TRIG:SOUR IMM
TRIG:DEL:AUTO ON
TRIG:COUN 1
SAMP:COUN 1
READ?
READ?
SYST:ERR?
SYST:ERR?
Example 1 - Single-point DC current measurement
This example performs the following operations:
Resets the unit and clears event register bits
Places the unit in DC current measurement mode in the fixed 1 A range with 1 μA of resolution
Keysight 34401A SCPI commands DMM6500 SCPI commands
Example 2 - Single-point DC voltage measurement with status and error checking
This example performs the following operations:
Resets the unit and clears the event bits
Configures the instrument for DC voltage measurement with autoranging applied
Sets the trigger and sample count values
Queries the instrument for the measurement
Keysight 34401A SCPI commands DMM6500 SCPI commands
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*RST
*RST
*CLS
*CLS
CONF:VOLT:DC:10.0 V,10mV
SENS:FUNC "VOLT:DC"
SENS:VOLT:DC:RANG 10
SENS:VOLT:DC:NPLC 1
DISP:VOLT:DC:DIG 6
TRIG:SOUR EXT
TRIG:DEL:AUTO 0.0000
TRIG:COUN 5
SAMP:COUN 10
ZERO:AUTO ONCE
SENS:VOLT:DC:AZER ON
TRIG:LOAD "Empty"
TRIG:BLOC:WAIT 1, EXT
TRIG:BLOC:DEL:CONS 2, 0.0
TRIG:BLOC:MDIG 3, "defbuffer1", 10
TRIG:BLOC:BRAN:COUN 4, 5, 1
INIT
INIT
*WAI
FETCH?
FETCH?
Example 3 - Use an external trigger signal to start a series of DC voltage measurements
This example performs the following operations:
Resets the instrument and clears the event register bits
Configures the instrument for DC voltage measurement with a fixed range
Configures the instrument to respond to five external trigger signals, each starting a series of ten
measurements
Auto-zeroes the instrument once prior to the start of measurements to remove any offset at the input
terminals
Initiates the trigger model
Queries the instrument to return all 50 readings
Keysight 34401A SCPI commands DMM6500 SCPI commands
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*RST
*RST
*CLS
*CLS
CONF:RES 1000.0, 0.01
SENS:FUNC "RES"
SENS:RES:RANG 1000.0
SENS:RES:NPLC 1
DISP:RES:DIG 6
TRIG:SOUR IMM
TRIG:DEL:AUTO 0.0000
TRIG:COUN 1
SAMP:COUN 20
ZERO:AUTO ONCE
SENS:RES:AZER ON
TRAC:CLE
CALC:FUNC AVER;STAT ON
DATA:FEED RDG_STORE, "CALC"
TRIG:LOAD "SimpleLoop", 20, 0
INIT
*WAI
READ?
TRAC:DATA?
CALC:AVER:AVER?
TRAC:STAT:AVER?
CALC:AVER:MIN?
TRAC:STAT:MIN?
CALC:AVER:MAX?
TRAC:STAT:MAX?
Example 4 - Read back calculated values
This example performs the following operations:
Resets the instrument and clears the event register bits
Configures the instrument for 2-wire resistance with a fixed range
Configures the trigger and sample count values
Auto-zeroes the instrument once prior to the start of measurements to remove any offset at the input
terminals
Initiates calculations on the buffer readings
Queries the instrument to return all 20 readings as well as the average, minimum, and maximum values
Keysight 34401A SCPI commands DMM6500 SCPI commands
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