Specifications
“We used square-wave output from the DMM for operational checks of digital circuits around an FPGA to verify the power source of a satellite tracking
device and the reception signal from GPS. The U1252A makes our job easier by providing multiple measurements and very accurate results.”
Hashiguchi, Engineer, ELM Inc., Japan – developer of satellite tracking and other system devices
What others say
Built-in square-wave generator for designing and troubleshooting motor drivers
In the motor-driver circuit shown, a
signal from the pulse-width modulation
(PWM) inverter drives the motor and is
fed back to the speed controller circuit.
In design and troubleshooting applica-
tions, these pulses are generated
externally—usually with a function
generator or pulse generator—and
injected into the circuit to simulate
actual pulses from the inverter.
With the U1250 Series, you can easily
confi gure the square-wave output of
the U1252B to generate simple PWM
signals—conveniently in one portable,
lightweight instrument.
Vdc
Motor
Speed reference
Torque
reference
Rotor flux
reference
Rotor flux
calculation
Speed
controller
Current
controllers
dq
dq
abc
abc
calculation
i
qs
i
ds
calculation
calculation
Speed
sensor
PWM
inverter
Specifi cations of the U1250 Series Digital Multimeters
U1251B U1252B U1253B
Display
Organic LED
N/A N/A Yes
Dual display
Yes Yes Yes
Counts
50,000 (both displays) 50,000 (both displays) 50,000 (both displays)
Analog bar graph
Yes Yes Yes
Backlight
Yes Yes N/A
Basic features
True RMS
AC AC+DC AC+DC
Basic DCV accuracy
0.03% 0.025% 0.025%
Auto/Manual ranging
Yes Yes Yes
Measurements
Voltage AC/DC
1000 V 1000 V 1000 V
Current AC/DC
10 A 10 A 10 A
Resistance
50 MΩ 500 MΩ 500 MΩ
Frequency
1 MHz 20 MHz 20 MHz
Capacitance
0.001 nF to 100 mF 0.001 nF to 100 mF 0.001 nF to 100 mF
Temperature
1372 °C, K-type thermocouple 1372 °C, J/K-type thermocouple 1372 °C, J/K-type thermocouple
Continuity with beeper
Yes Yes Yes
Diode test
Yes Yes Yes
4-20 mA % scale
Yes Yes Yes
dB
Yes Yes Yes
Frequency counter
N/A Yes Yes
Smoothing function
N/A N/A Yes
represents key specifi cations/features
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