DMM Fluke 289 (Used)

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This has been the top multimeter from Fluke for many years. Here I am looking at my old (2009) copy of the meter. This means I cannot say anything about the box or accessories it was delivered with.

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The range switch is fairly easy to turn and with this heavy meter it is stable both lying and standing.

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The meter needs 6 AA batteries.

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There is 3 connection on the meter, but only two on the battery tray.




Display

The meter uses a graphical display, this means fairly low contrast, but it can show many different layouts. To get the pictures here I used the background light on the display.

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The meter has a build in manual.

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A fairly simple display for showing volt DC. The soft keys shows the usual functions:
Menu: Options for the current selected range.
Save: Save one or more values or look at the saved values.
Empty: Use for some shortcuts and range specific functions.
Setup: General meter setup and calibration.

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Here is the "Menu" for DC, the arrow keys are used to move the black square around and each location has one or more functions. For this menu there are a total of 10 functions (VDC, Rel, Rel %, Peak, AC+DC, AC,DC, DC,AC, Hz, %, ms).

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The min/max (and peak) display shows all the values at once, including time stamps for when the event occured.

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Continuity shows resistance, bargraph and a graphic on open/short. There is a shortcut key to change between ohm and continuity, to avoid using the menu button (For nS the menu must be used.

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When current ranges is selected a warning will be shown until leads are plugged into the current terminals.
If leads are in the current terminals in other ranges both the warning and the buzzer will be used to warn.

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The meter saves data in record sets with data time and samples. Events is used to capture changing values that happens between sample intervals and will add extra sample points. Default setting is that a 4% change will add a event, but it can be adjusted.

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The meter can also show captured data in graphical form and it is possible to zoom on the data.

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The setup function makes it possible to see some information about the meter (Like calibration data and software versions) and adjust a couple of preferences.

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Here is most of the preferences.
Secondary display functions (After / is secondary values):

Functions

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Buttons: Rotary switch:

Input

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Measurements 1uF

A look at the capacity measurement waveform with a 1uF capacitor

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The input resistance in mVDC

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LowZ input is a PTC, this means it starts at a fairly low value and will increase resistance with voltage.

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The high mA range is only rated for 400mA (Due to the fuse), it will start flash at 440mA and can show up to 550mA
The 500Mohm range will only show 66Mohm on my decade resistor, but correctly 100Mohm on a test resistor (Reference meter show 100Mohm in both cases).



Computer connection

The software from Fluke is called "FlukeView Forms" and I believe that is the only way to get the communication cable. I bought the software with my meter, but have never really used it. It is designed to collect data from the meter and make a final report, it has some standard templates and it is possible to define you own templates for this in the extended version of the software. The software can both log data directly from the meter and download saved data from the meter.

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I have used the interface a lot with my own software to log data from the meter.

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The interface plugs into the meter, but is not locked tight. Moving the meter around or pulling in the cable will likely disconnect it, but it do not fall out by itself.



Tear down

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Six screws and the back could be removed, four of them are under the battery cover.

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All 3 connections from the batteries are connected to the circuit board.

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There is a inner cover in conductive plast. it is difficult to get a connection, but when you get there is less than 25ohms from one end to the other.

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The range switch uses a different type of wipers compared to most other multimeters.

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Again the internal cover.

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The top of the meter is made of clear plastic with the yellow layer over it.

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The voltage input has two paths, one is a 1kOhm (R4) resistor followed by a PTC (RT1) and then clamped by two MOVs (RV3 & RV1) in series. The other path is a ceramic resistor (Z1: 1Mohm) clamped by two MOVs (RV2 & RV1) in series. The LowZ is handled by a PTC (RT2). The range resistors for the voltage input is the other ceramic resistor (R61:10MOhm+more). The AC capacitor beside the MOVs (C3: 22nF 1000V).
The 10A current shunt is a 4 terminal wire shunt (R5), the mA shunt is a power resistor (R165: 1ohm) and the uA shunt is a smd resistor (R167: 100ohm).
At the input is a couple of muxes (U9: Unknown, but probably a mux), (U12, U39, U40: 4053), then there are the ADC circuit with a ADC (U10: LT2415-1, 24 bits), reference (U42: LT1019ACS8-2.5 0.05% 5ppm) and rms converter (U14: LTAFG/LTC1968). This is controlled from a mixed signal processor (U13: M430F448 16bit risk, 48KB+256B flash, 2KB ram). The display must have a controller build in, there is only a few wires to it (J3).

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There was missing some stuff on the top side of the circuit board. Here is the detection of terminals, it is done with a light emitter (DS2) and two receivers (Q24 & Q27). There is also the uAmA protection diodes (CR14: Bridge & CR15:Diode).
A high quality mux (U48: ADG714) is placed on this side.
There is also a processor more (U26: MC9328MXS, ARM9) with flash memory (U28: 640P30 64Mbit) and probably some ram (U25, U27). This must be the processor that handles the user interface.
At the top of the board is the IR link (CR1 & DS1)

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Conclusion

This meter is a very precise high-end meter with just about any function that is possible. Because the screen is alphanumeric it is fairly easy to navigate around on the meter and it can also pack a lot of information on the screen. But the screen is also one of the problems with the meter, it has fairly low contrast and is best read with the background light on or under a bright lamp. Another problem is the user interface, using arrow keys to select functions are not as fast as a dedicated button, the processors in the meter means it is on the slow side to power on.

Generally I like the meter and have used it on the bench and for logging with a computer (More than 1000 hours). I dislike the low contrast on the display and the slow power on, but for min/max/average this is my favorite meter. If I needed to do off-line logging this meter would also be in top.



Notes

I have removed the super capacitor (C145) from my meter (It was starting to leak), this means it cannot remember date/time when replacing batteries. Because I usual do not use date/time (Time stamp is added by my logging software) they are not set correctly.

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