The meter comes with a 9V battery, but can also be powered independently through the 5V USB connection. It will keep working, even if the 9V battery is removed.
The USB datalogging stream is sent to the computer through the same USB connector. The meter comes with a CD containing the dedicated software and some user notes in English.
There is an auto detection of components, which is the standard configuration at power-up, with a manual selection also possible, through a toggle switch, labelled 'FUNC".
The standard 1 kHz frequency can be modified at any time and the secondary parameter can also be changed, when in manual mode.
Automatic serial/parallel mode selection is done according to device under test, with manual override possible in manual mode.
Other functions are:'Sorting'
mode, (manual selection of % deviation) with a Pass or Fail message. (0.25%, 0.5%, 1%, 2%, 5%, 10%, 20% and +80%~-20%)
Sorting is only available in manual mode with an ideal DUT connected to the meter. Pressing 'SET UP' will allow you to change the range of the ideal reference device, using the lateral arrow keys. Pressing 'ENTER' will now allow you to change the value of the reference DUT, using all arrow keys. Another press of 'ENTER' will bring you into the tolerance selection.'Calibration'
mode, to null the test leads or tweezers with shielding and guard connection.
Press 'CAL' to access 'Open' mode, with an open circuit (loose test leads), then 'CAL' again to enter a countdown to 30s. 'PASS' or 'FAIL' should appear on screen. Press 'CAL' again, if the first test was successful, to enter the 'Short' mode, with a closed circuit (shorting bar or test leads connected together) then 'CAL' again for a 30s countdown with 'PASS' or 'FAIL' message. Press 'CAL' again to exit this mode.
Calibration should be done each time accurate measurements are required or if different test leads are connected.'Relative'
mode to display a deviation as a %, from a reference DUT. It is only available in manual mode. Pressing 'REL' to access the feature, brings up a triangular icon on screen. Connecting another similar device, will display a difference in value as a percentage of the initial measurement. Pressing 'REL' again will display the initial value with a flashing triangle (delta) as a warning. A long press of 'REL' will exit this mode.'USB'
mode, to send a data stream to logging computer. The data consists of primary value, mode and unit, secondary value, mode and unit and the testing frequency. A computer icon appears in the screen. APO goes off, as soon as the USB cable provides 5V to the meter. The Baud rate is 9600.4.Usage:
The LCD is easy to read, but is best seen from a slight angle (10 to 20 degrees from vertical), just like the CEM DT-9935. All the UT612 meters seem to behave the same way, so it was either designed like that or UNI-T and CEM bought a whole batch of faulty LCDs a few years ago.
It isn't really an issue, once you're aware of the unusual behaviour.
The backlight is fairly strong and evenly spread and will last for 60 seconds after activation.
The LCD has a bargraph, marked as a percentage of full range (20,000 count). For example, a 100 ohm resistor will register as 50%.
There is a reduced count of easy access buttons, compared to other meters, making it easy to make the right selections in a minimum of time.
Convenient use of USB for both logging and external power ( works great, unlike the Mastech external power unit)
It comes in a fairly small size (224mmx172mmx59mm), just a little bit bigger than the UT61E. No unnecessary bulk, like on the Mastech behemoth.
It is light, with a single 9V battery.
It comes with a great hard protective storage case, like the IET 5000 meter, which is quite unusual at that price point.
It has 10 reliable solid state buttons instead of a multitude of soft PCB contact buttons like on most other meters (14 on the CEM LCR meter).
One has no control over the APO (Auto Power Off). It is always active with the battery, but goes off when powered through USB. After 3 beeps, the meter will auto shutdown after about 6 minutes of inactivity, when powered by the battery.
The piezo beeper can be heard loud and clear, unlike the one in the CEM meter, which is rather quiet.
The SMD tweezers come with an extra shield lead for connection to one of the guard jacks.
Low battery warning and shutdown is triggered at 5.5V.
Available frequencies are: 100Hz, 120Hz, 1KHz, 10KHz and 100KHz.
The measured secondary parameters are Q, D, ESR, Rp and Theta.
The shielding test lead connection to Guard should be used while measuring resistances above 10M Ohms, to minimize noise and parasitic effects.
Large caps should be measured in series at 120Hz, small ones in parallel, at 1 KHZ, if less than 0.01 uF. Large filter inductors above 200H, should be measured at 120Hz, small audio/RF inductors at 1 or 10 KHz, if less than 2 mH.5.Limitations:
20,000 count on primary display, 2,000 count on secondary.
No voltage can be applied to the jacks.
There is no input protection.
4 wire measurement is possible (removing PCB trace resistance only, not contact point resistance) with the special jack adapter, but doesn't work with Kelvin testing leads.
No DC bias can be applied to the jacks.
The meter impedance is 120 Ohms and the test current is 4.5mA~5mA RMS.6.Construction:
The 2 halves of the meter can be easily separated, by disconnecting the joining wires, if required. The USB PCB is held in place by one screw and the battery wires and battery connector can be threaded through, once a little trap door with clips is removed. There is no shielding in the bottom piece, just like all the meters using this chipset.
4 self-tapping screws are holding the main PCB in place.
Don't undo the topmost screws which secure the backlit LCD to the PCB, unless you have to. 2 LEDs are installed for backlighting through a large diffuser. The whole LCD/diffuser/Zebra connectors/LEDs contraption is difficult to put back together correctly, even after careful dismantling.
It is a double-sided PCB, with a limited number of components, as the chipset does most of the work:
U1 Cyrustek ES51919Q
U2 Cyrustek ES51920A
(Not the S model, like the CEM or Mastech)
U3 24C02H Serial I2C EEPROM 2KB
U4 TI 430G2202 2KB flash 256B RAM 20-TSSOP uController
U5 3.5V voltage regulator
U6 5.0V voltage regulator
U7 TI AEH7M Multiplexer/De-multiplexer
U8 TI AEH7M Multiplexer/De-multiplexer
1 VR trimpot (probably Ohm adjustment)
2 crystal oscillators (3.999/24.000)
There is also a small separate PCB for the USB connector in the bottom shell. 3 unsightly wires provide USB data link and power connection. The wires are soldered directly to the PCB, instead of connectors, then covered with sealant to provide some stress relief.