DMM Keysight U1233A

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Keysight is on of the very large test and measure manufacturers, with anything from simple DMM to highly advanced and expensive measure equipment. This meter is one of the simple DMM's, I have taken the most advanced meter in this product series (U1230 series).

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The meter arrived in a box that is used for all DMM's in this series.

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The box included the meter, batteries, probes, a calibration certificate, safety instructions and quick start guide. A full manual can be downloaded from Keysight.
A thermocoupler is not included, but it can use any K-type with banana plugs.

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The probes are branded Keysight and rated for 10A and 1000V

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A protection for the tip is included.

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The plug is fully shrouded and standard size.

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The meter can be held in a hand and range changed with the same hand, because the range switch is accessible from the side.

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The tilting bale has multiple positions.

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In the top position the meter can be hanged on something.

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There is a flashlight on the back of the DMM and a port for a IR/usb communication cable or a bluetooth transmitter (Keysight sells both).

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Both batteries and fuse can be easily replace. uA do not need a fuse, but uses the general input protection on that terminal.

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Display

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The above picture shows all the segments on the display. To activate this hold down the "Trig Auto" button during power on.

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During turn on the meter will usual show the model number.

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Typical display during usage, it will show the number and what measurement is selected.
The bargraph will reflect the measured value, but updates much faster than the numbers.
The APO sign shows that auto power off is enabled, time and enable/disable can be changed in the configuration menu.

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The electric field detection (NCV) has two ranges Hi and Lo, the bargraph indicates strength and the buzzer and a red led will signal if any field is detected.



Functions

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Buttons: If meter is powered on in config menu mode (Esc/Shift held down when turned on) all the buttons are used for navigation.

Rotary switch:
Input

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Measurements
1uF

A look at the capacitance measurement waveform.

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Input impedance in LowZ mode.

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Configuration

This meter has a configuration menu, it is activated by holding down "Esc/Shift" during power on. The settings are:

Flashlight menu

Holding down the light button during power on will start the meter in flashlight mode. When in this mode it is possible to directly adjust the brightness of the flashlight and select a SOS (Help) mode.
There is also a "Demo" mode where the meters flashes backlight, flashlight and beeps.



Scale conversion

By holding down the Min/Max button during power on the meter will start in a scale conversion mode (in V ranges). This means it will measure volt, but display it with a conversion factor. This is designed for use with current clamps, high voltage probes or thermometer adapters.
The actual conversion is selected in the configuration menu, there is 5 current conversions, one temperature and one voltage.



Software

Keysight has multiple software packages for use with the meter, they are free to download. The software is designed for many different DMM models and not all functions are available with this meter.

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The usb adapter is sticking out and the meter cannot lay flat on a table.



GUI DataLogger

This is a fairly simple software designed for handling one meter.

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It can log data or show the meter reading.

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It is possible to define logging options.



Keysight Handheld Meter Logger

This software can log data for multiple meters and requires a "License manager" on the computer (It will install automatically).

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Notice the "Layout View" selection at the top, up to 9 curves can be show on the screen.



Tear down


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There was only two screws, before I could remove the back (The battery cover is still in place).

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To get the circuit board out I only had to remove the nuts on the terminals. There was also some clips midways on the circuit board.

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The back has shielding, the buzzer and a lens for the flashlight.

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The handle for the range switch is on the front, the actual switch is on the circuit board. There is some plastic shields that goes through the circuit board to isolate fuse and input resistors.

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The circuit board are designed to use all the space.

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On this side is the range switch, the backlight led and the indicator led at the top of the display.

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This DMM do not use a DMM chip with everything in, there is a 20bit ADC (U12: AD7781) and a 8 bit microcontroller (U1: D78F0485). The led for the flashlight is mounted on the circuit board next to the xtal. Some distance below that led is the two leds for the communication cable (DS1 & CR9) one a transmitter, the other a receiver. The chips marked CM052B and CM053B are CD4052 and CD4053 analog switches, there is also a high quality switch MAX4582. There is a 74HC595 8 bit shift register and a few LM385 references.
The input circuit has two large resistors followed by some PTC's (RT1, RT2, RT3) and two gas discharge over voltage protections (E1 & E4). One of the PTC's is probably used for the Low-Z mode. C1 looks like it might be the input capacitor for AC and it is connected to a 10Mohm divider chain (R3, R4, R5, R6, R7) with a capacitor across (Cc) for better AC response.
The Vsense (NCV) antenna is placed at the top behind/besides the indicator led.

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Conclusion

The meter has all nearly normal DMM function, mA and duty cycle is missing, but it adds Low-Z, NCV, Average, a very nice auto hold feature, flashlight, fast bargraph and communication (Requires extra cable). There is also a configuration menu making it possible to adjust backlight timeout, power off timeout and some other details.
The high uA range has a fairly high burden voltage (Up to 1.8V) and a very good input protection.

Being from Keysight I have no doubt the CAT rating is correct on this meter, this means it can be used at fairly high voltage and current.

I miss the mA range, but generally I like this meter.



Notes

The U1231A and U1232A is the same multimeter, but some function and ranges are missing.

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