Agilent U12xxx series

The Agilent U12xxx series are handheld digital multimeters, ranging from inexpensive all-purpose meters to industrial meters.

Model	Counts	Supported
U1231A	6000	Yes
U1232A	6000	Yes
U1233A	6000	Yes
U1241A / U1241B	10000	Yes
U1242A / U1242B	10000	Yes
U1251A / U1251B	50000	Yes
U1252A / U1252B	50000	Yes
U1253A / U1253B	50000	Yes
U1271A	30000	No
U1272A	30000	No
U1273A	30000	No
U1273AX	30000	No

Is your model not supported yet? Get in touch! We need people to help us test other models in this series, and getting a new model supported is generally quick & easy.

Connection

All models communicate via an optically isolated serial connection, at 9600 bps, 8 bits, no parity, and 1 stop bit (9600/8n1). Connecting to the devices can be done either via USB (U1173A cable) or Bluetooth (U1177A interface).

Protocol

All models in this series use generally the same protocol, with only minor differences between models -- and none within the same range.

*IDN?

Sending the command *IDN? causes the device to return a comma-separated four-field string, compatible with the identical GPIB command. The four fields are vendor name, model name, serial number and version:

Agilent Technologies,U1232A,MY52020136,V1.00

*RST

Sending the command *RST causes the device to reset. The response is an asterisk followed by the current dial position, for example *1 indicates the first position.

SYST:BATT?

The command SYST:BATT? returns a value indicating the device's battery level. The value is in a different format depending on the model series:

The U123xx models return a percentage value, like this:

36%

The U124xx models return a value like this:

+1.04200000E+02

SYST:BEEP

The command SYST:BEEP TONE make the multimeter emit a beep.

SYST:BLIT

The commands SYST:BLIT 1 and SYST:BLIT 0 turn the screen backlight on and off. There is no response. The backlight timer will still run and turn the backlight back off again if it is enabled.

FETC?

The FETC? command returns the current measured value, as a floating point ASCII string, as in the following examples:

+9.25000000E-03
+0.00000000E+00
-1.01140000E+00
-9.10200000E-01

The sign characters are always present, and the value is always in normalized scientific format. This applies even when in a mode that uses integer numbers, 11 would be transmitted as +1.10000000E+01. If no valid measurement is available, i.e. the display shows "OL" or "-OL", the transmitted value is either +9.90000000E+37 and -9.90000000E+37 respectively.

CONF?

The CONF? command queries the device's current measurement configuration.

U123xx models

This can be either one, two or three comma-separated fields. The number of fields depends on the first field's value, but the second field always denotes the measurement mode's range and resolution, and the third field is the current type (AC or DC). For example, this indicates AC voltage in the 600mV range:

V,0,AC

Mode	Resolution	Current	Meaning
V	y	y	Volts
	0		Range 600mV, resolution 0.1mV
	1		Range 6V, resolution 1mV
	2		Range 60V, resolution 0.01V
	3		Range 600V, resolution 0.1V
MV	y	y	Millivolts
	1		Range 600mV, resolution 0.1mV
A	y	y	Ampere
	0		Range 6A, resolution 1mA
	1		Range 10A, resolution 0.01A
UA	y	y	Microampere
	0		Range 60μA, resolution 0.01μA
	1		Range 600μA, resolution 0.1μA
FREQ	y	y	AC frequency
	0		Always shows 0, even when the range is changed manually on the device. This is possibly a firmware bug.
RES	y	n	Resistance
	0		Range 600Ω, resolution 0.1Ω
	1		Range 6kΩ, resolution 0.001kΩ
	2		Range 60kΩ, resolution 0.01kΩ
	3		Range 600kΩ, resolution 0.1kΩ
	4		Range 6MΩ, resolution 0.001MΩ
	5		Range 60MΩ, resolution 0.01MΩ
CAP	y	n	Capacitance
	0		Range 1000nF, resolution 1nF
	1		Range 10μF, resolution 0.01μF
	2		Range 100μF, resolution 0.1μF
	3		Range 1000μF, resolution 1μF
	4		Range 10mF, resolution 0.01mF
DIOD	n	n	Diode

U124xx and U125xx models

The output consists of the meter's mode, followed by a space, and then the meter's upper and lower ranges in that mode, separated by a comma. The mode may optionally include a colon followed by a code denoting a submode relevant to that major mode. For example, this is the AC voltage in the 1000mV range:

VOLT:AC +1.000000E+00,+1.000000E-04

Mode	Meaning
VOLT	Voltage, submode can be AC
CURR	Current, submode can be AC
FREQ	Frequency counter
DIOD	Diode check
CONT	Continuity
RES	Resistance
CAP	Capacitance
SCOU	Switch counter
CPER	Current loop, submode can be e.g. 0-20mA or 4-20mA.
T1 or T2	Temperature, submode can be K or J, denoting the thermocouple type. Instead of range, CEL or FAR is given, denoting the measurement is in Celcius or Fahrenheit.

STAT

The STAT? command is used to query the current state of the device. The response is a quoted 21-byte string, like this:

"000000000110L00000000"

U123xx models

Byte	Value	Meaning
1		Max/min/avg mode
	0	Off
	1	On
2		Relative measurement. The last value returned from FETC? before this mode was enabled denotes the stored reference value.
	0	Off
	1	On
3		Trig hold-log
	0	Off
	1	On
4		Auto hold-log
	0	Off
	1	On
5		LED flashlight
	0	Off
	1	On
6		LCD backlight
	0	Off
	1	On
7		Smoothing
	0	Off
	1	On
8		Temp/aux mode. When on and rotary switch is in position 5 (capacitance), CONF? returns MV,1,DC, but the value returned from FETC? instead denotes the temperature, in the unit (F or C) according to the meter's configuration.
	0	Off
	1	On
9		Unknown (always 0)
10		Beep frequency
	0	4.2kHz
	1	3.8kHz (default)
	2	3.4kHz
	3	3.2kHz
	4	Off
11		Auto power-off (APO)
	0	Off
	1	On
12		Unknown (always 0)
13		Unknown (always L)
14-15		Unknown (always 0)
16		Rotary switch position
	0	V/Zlow
	1	Voltage AC
	2	Voltage DC
	3	Resistance
	4	Diode
	5	Capacitance
	6	Current
	7	Microcurrent
17		Continuity mode. When enabled, the value returned from FETC? is either NAN (no continuity) or any real value to denote continuity.
	0	Off
	1	On
18		Unknown (always 0)
19		Battery low indicator
	0	Battery OK
	1	Battery low
20-21		Unknown (always 0)

U124xx models

Byte	Value	Meaning
1		Max/min/avg mode
	0	Off
	1	On
2		Relative measurement. The last value returned from FETC? before this mode was enabled denotes the stored reference value.
	0	Off
	1	On
3		Unknown
4		Unknown
5		Unknown
6		Current loop mode
	0	0-20mA mode
	1	4-20mA mode
7		Unknown (always I)
8		Hold mode.
	0	Off
	1	On
9		Unknown
10		Beep frequency
	0	Off (no beeps)
	C	300Hz
	F	600Hz
	1	1.2kHz
	2	2.4kHz
11		Auto power-off (APO)
	0	Off
	1	On
12		LCD backlight
	0	Off
	1	On
13		Unknown (always L)
14		Unknown
15		Unknown
16		Rotary switch position
	0	Voltage
	1	Diode
	2	Resistance
	3	Capacitance
	4	uA
	5	mA
	6	A
	7	Temperature
17		Unknown
18		Unknown (always 1)
19		Unknown
20		Switch counter mode
	0	increase count on rising flank (initially low)
	1	increase count on falling flank (initially high)
21		Auto range
	0	Off
	1	On

U125xx models

Byte	Value	Meaning
1		Max/min/avg mode
	0	Off
	1	On
2		Relative measurement. The last value returned from FETC? before this mode was enabled denotes the stored reference value.
	0	Off
	1	On
3		dB mode
	0	Off
	m	?
	V	?
4		Unknown
5		Peak hold mode
	0	Off
	1	On
6		Current percent
	0	0-20mA
	1	4-20mA
7		Triggerhold I/B ?
8		Triggered hold mode.
	0	Off
	1	On
9		Zero temperature compensation?
10		Beep selection ?
11		Auto power-off (APO)
	0	Off
	1	On
12		LCD backlight
	0	Off
	1	On
13		Unknown (always L)
14		Unknown (always 0)
15		Unknown
16		Rotary position ?
17		Output status active/standby ?
18		Unknown
19		Battery low indicator
	0	Battery OK
	1	Battery low
20		Frequency counter prescaler
	0	No prescaling
	1	Divide by 100
21		Auto range
	0	Manual range
	1	Auto range

Resources

• Series overview
• Documentation