Keysight Technologies U1281A Operating instructions

Keysight U1281A/U1282A
Handheld Digital Multimeter
Programming
Guide

2Keysight U1281A/U1282A Programming Guide
Notices
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U1281-90001
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Edition 1, July 22, 2015
Printed in Malaysia
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Keysight U1281A/U1282A Programming Guide 3
Table of Contents
1 Introduction
Configuring the IR interface 6
Introduction to Remote Commands 7
2 Remote Commands
U1281A/U1282A Configuration Overview 12
*IDN? 13
*RST 14
*CLS 15
ABOR 16
CALC:AVER 17
CALC:PEAK 18
CONF? 19
FETC? 20
INIT 21
READ? 22
STAT? 23
SYST:BATT? 26
TRIG:SOUR 27
TRIG:REF:COUN 28

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Keysight U1281A/U1282A
Handheld Digital Multimeter
Programming Guide
1 Introduction
Configuring the IR interface 6
Introduction to Remote Commands 7
Syntax conventions 7
Querying parameter settings 8
Returned result 8
Prompts 8
This chapter describes the parameters that configure the U1281A/U1282A, and helps you
determine the settings to achieve optimum performance.

1Introduction
6Keysight U1281A/U1282A Programming Guide
Configuring the IR interface
The U1281A/U1282A may be operated via an IR interface. The remote control operation
will enable you to manually operate the multimeter via a terminal, or to automatically
execute a host computer program.
The default parameters for the U1281A/U1282A are:
–Baudrate:9600 bits per second
– Parity bit : None
– Data bits : 8data bits
– Number of Stop Bits : 1bit
Ensure that the serial port terminator to CR/LF is configured for both the transmit and
receive settings.
Each time after a *RST command is sent to the U1281A/U1282A, the communication
buffer (transmit and receive) must be cleared before the next command is sent.
In order to ensure smooth communication, allow sufficient time for the U1281A/U1282A to
respond to each command. In most cases, this means refers to a 5-second delay after the
*RST command and a 200-millisecond delay for all other commands.
For situations where the above delay is insufficient and is related to the serial port
hardware, operating system (OS) serial communication buffer, or the central processing
unit (CPU) response time, you may consider increasing the delay time to maintain stable
communication with the U1281A/U1282A.
NOTE
– The Carriage Return (CR) character (0x0D, \r) moves the cursor to the beginning of the
line without advancing to the next line. This character is used as a new line character in
Commodore and Early Macintosh operating systems (OS-9 and earlier).
– The Line Feed (LF) character (0x0A, \n) moves the cursor down to the next line without
returning to the beginning of the line. This character is used as a new line character in
UNIX-based systems (Linux, Mac OS X, etc.).
– The End Of Line (EOL) sequence (0x0D0x0A, \r\n) is actually two ASCII characters—a
combination of the CR and LF characters. It moves the cursor both down to the next
line and the beginning of that line. This character is used as a new line character in
most other non-Unix operating systems including Microsoft Windows, Symbian OS, and
others.

Introduction 1
Keysight U1281A/U1282A Programming Guide 7
Introduction to Remote Commands
Remote commands control instrument functions. A subsystem command has a hierarchical
structure that usually consists of a top-level (or root) keyword, one or more lower level
keywords, and parameters. The following example shows a query and its associated
subsystem:
CALC is a root level keyword with AVER as the second level keyword, and MAX as the
third-level keyword.
Syntax conventions
Throughout this programming guide, the following conventions are used for remote
command syntax:
– Square brackets “[ ]” indicate optional keywords or parameters and can be omitted. The
brackets are not sent with the command string. If you do not specify a value for an
optional parameter, the instrument chooses a default value.
– Braces “{ }” enclose one or more parameters that may be included zero or more times.
The brackets are not sent with the command string.
– Triangle brackets “< >” indicate that you must substitute a value for the enclosed
parameter. The brackets are not sent with the command string.
– Parentheses “( )” enclose parameters that are usually a channel list.
– Vertical bars “|” can be read as “or” and are used to separate alternative parameter
options.
Only short form commands are recognized by the instrument. For example, consider the
keyword TRIGger. Only the short form—which is TRIG—will be recognized by the
instrument. Other forms, such as TRIGG, TRIGge, or even TRIGger, will generate errors. An
example of the command syntax format is illustrated below:
-> CALC:AVER:MAX?
-> TRIG:SOUR <BUS|REF|IMM>

1Introduction
8Keysight U1281A/U1282A Programming Guide
Querying parameter settings
You can query the current value of most parameters by adding a question mark (?) to the
command. For example, you can query the function of the primary display measurement by
sending:
Responding Message
Returned result
After the U1281A/U1282A executes a query command, the return of the result will be in the
following format:
On the multimeter warning the returned prompts will be in the following format except Xon
and Xoff:
Prompts
The U1281A/U1282A will generate a system warning by sending a prompt string to the
host through the remote interface when the U1281A/U1282A has a status change as listed
in the table below.
-> CONF?
<- <Result> + <CR> <LF>
<- <Prompts> + <CR> <LF>
Prompt Description
﹡LLocal mode
﹡CCalibration mode
﹡ERemote command error warning
﹡BLow battery warning
﹡IInput warning (Please refer to STAT? command)
﹡0Rotary position: ACV measurement
﹡1Rotary position: ACmV measurement
﹡2Rotary position: ACDCV measurement
﹡3Rotary position: ACDCmV measurement
﹡4Rotary position: RES/CONT measurement

Introduction 1
Keysight U1281A/U1282A Programming Guide 9
﹡5Rotary position: Diode/Hz measurement
﹡6Rotary position: CAP/TEMP measurement
﹡7Rotary position: uA/mA measurement
﹡8Rotary position: A measurement
﹡9Rotary position: SQU output
ASC(&H11) Xon: The meter is available
ASC(&H13) Xoff: The meter is busy
Prompt Description

1Introduction
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Keysight U1281A/U1282A
Handheld Digital Multimeter
Programming Guide
2 Remote Commands
*IDN? 13
*RST 14
*CLS 15
ABOR 16
CALC:AVER 17
CALC:PEAK 18
CONF? 19
FETC? 20
INIT 21
READ? 22
STAT? 23
SYST:BATT? 26
TRIG:SOUR 27
TRIG:REF:COUN 28
This chapter describes the U1281A/U1282A remote commands.
NOTE
Ensure that you have configured the U1281A/U1282A before using any of the remote
commands. Refer to “U1281A/U1282A Configuration Overview” on page 12. For more
details, refer to the U1281A/U1282A User’s Guide.
NOTE
Due to the unique Export Log feature of the U1281A/U1282A, you will need to handle the
exporting of data when using any of the following functions:
– Trigger Hold
–AutoHold
– Manual Log
– Interval Log
– Event Log
–ExportLog
When you send a command related to any of the above functions, the U1281A/U1282A will
return additional information on export log data. If this is not handled properly, it will cause
wrong data to be fetched and an exception error to occur. Therefore to always ensure
correct data is fetched, it is recommended not to use the above functions during
programming.

2 Remote Commands
12 Keysight U1281A/U1282A Programming Guide
U1281A/U1282A Configuration Overview
When the above configuration has been made, you can proceed to use the remote
commands in the following sections.
A
mA COM
V
V
A
V
mV
mV
U1282A True RMS Multimeter
mA
Vsense
Peak Vsense
Dual
Auto
FUSED
440mA CAT III 1000V
600VCAT IV
MAX
10A MAX
FUSED
OUT
OUT
MHz
RMT
3
1
2
Use the keypad to configure measurement
settings.
Turn the rotary switch to the desired
measurement function.
Connect the test leads to the appropriate
input terminals according to the selected
measurement function.

Remote Commands 2
Keysight U1281A/U1282A Programming Guide 13
*IDN?
Syntax
*IDN?
Description
The *IDN? query allows the U1281A/U1282A to identify itself by returning the model
number, serial number, and the firmware version. The string returned is, for example:
Keysight Technologies,<model number>,<serial number>,VXX.xx
where:
–<model number> identifies which U1281A/U1282A model is being used.
–<serial number> uniquely identifies each U1281A/U1282A.
–VXX.xx represents the firmware revision with XX and xx representing the major and
minor revisions respectively.
Example
-> *IDN? Returns the model number, serial number,
and the firmware version of the multimeter.
<- Keysight Technologies,U1282A,DPQ1007000,V1.00

2 Remote Commands
14 Keysight U1281A/U1282A Programming Guide
*RST
Syntax
*RST
Description
The *RST (reset) command places the U1281A/U1282A in the power-on-reset state without
shutting down the line power and returns the current rotary knob position (refer to
“Prompts” on page 8for a legend on rotary knob positions). The interface parameters will
return to their default values (refer to “Configuring the IR interface” on page 6).
Example
-> *RST
Places the instrument in the power-on-reset
state and returns the instrument to the
ACmV rotary switch position.
<- *1

Remote Commands 2
Keysight U1281A/U1282A Programming Guide 15
*CLS
Syntax
*CLS
Description
The *CLS (clear status) command clears the event registers in all register groups. This
command also clears the Error queue.
Example
-> *CLS The following command clears the event
register bits.

2 Remote Commands
16 Keysight U1281A/U1282A Programming Guide
ABOR
Syntax
ABOR
Description
This command places the trigger hold system in the idle state.
The display will show a dash (–) until the INIT command is triggered.
Example
Remarks
This command is only available in trigger hold mode.
-> ABOR Places the trigger hold mode in the idle state

Remote Commands 2
Keysight U1281A/U1282A Programming Guide 17
CALC:AVER
Query
CALC:AVER:MAX|MIN|AVER|PRES|COUN?
Description
This query returns the value of the specific dynamic recording function.
– MAX returns the maximum recorded value
– MIN returns the minimum recorded value
– AVER returns the average recorded value
– PRES returns the present recorded value
– COUN returns the count value of the average mode
Example
-> CALC:AVER:MAX? Returns the maximum recorded value
<- +2.63782000E+00

2 Remote Commands
18 Keysight U1281A/U1282A Programming Guide
CALC:PEAK
Query
CALC:PEAK:MAX|MIN?
Description
This query returns the value of the peak-hold function.
– MAX returns the maximum recorded value
– MIN returns the minimum recorded value
Example
-> CALC:PEAK:MAX? Returns the maximum peak-hold value
<- +2.83752000E+00

Remote Commands 2
Keysight U1281A/U1282A Programming Guide 19
CONF?
Query
CONF? [@2]
Description
This query returns a series of comma-separated fields indicating the present measurement
function of the primary or secondary display.
The query is returned in the following format string: <“Function”, “Range”,
“Resolution”>.
When the @2 parameter is omitted, the query returns the function of the primary display.
Example
-> CONF? Returns the function of the primary display
<- VOLT:AC +6.00000000E+01,+1.00000000E-03

2 Remote Commands
20 Keysight U1281A/U1282A Programming Guide
FETC?
Syntax
FETC? [@2|@3]
Description
This query returns the value of the primary or secondary display.
When the @2 parameter is omitted, the query returns the value of the primary display.
The @3 parameter corresponds to the environment temperature.
Example
-> FETC? Returns the value of the primary display.
<- +1.23475000E+00