Accumeter VI

[ikumi5]

my resistivity meter i build from scratch

[Unregistered]

4 probe earth resistivity meter

Sorry for not getting back on this... I need to take some oscope measurements still, but basically the inverter output is a 24 volt p-p square wave. It is taken off some internal point of the power inverter.

Folks, please don't use a power inverter, and put 120vac on the probes! Very dangerous!

Also, the big cap is 1000uF @ 63v.

I'll try to make some time to finish the measurement, and post a formal schematic.

- Carl

hi,
i have made already my homemade 4 probe earth resistivity meter,patterned to Accumeter VI, through the help of Carl....and i want to thank you for all the help....now, my question is, why would the Accu people use only 24 volts, and tim use 100 volts for his GCG......is there an advantage for this, coz im planning to use my 220 volts instead of 24, bypassing my transformer, if there is an advantage of using higher voltage...thanks

[Unregistered]

higher voltage

hi carl,

may i know the advantage of using higher voltage other than 24vac for earth resistivity meter, say 220vac?

thank you

[Carl-NC]

It's just a matter of Ohm's law... if your ground resistance is high, then a higher voltage might be necessary to produce a given current. One obvious implication is that for a lower voltage, probe spacing will be more limited.

If I'm not mistaken, most 4-probe ERMs pump a fixed AC current and measure the resulting voltage. Off the top of my head, I don't remember why. It doesn't change the issue with max voltage, though.

- Carl

[Alex]

where can I find the schematics ,PCB , for resistivity meter?

I saw the resistivity meter of Ikumi 5.Nice device.Where are the schematics ,PCB and other information for trying to build one please?
Somebody can help me?

[Unregistered]

resistivity meter

I saw the resistivity meter of Ikumi 5.Nice device.Where are the schematics ,PCB and other information for trying to build one please?
Somebody can help me?

hi alex,

the 2 probe "4probe" resistivity wiring diagram and some info are posted here already by Carl.....the pcb is very simple...just a matter of soldering...

[Alex]

MESSAGE FOR IKUMI

In the forum there are only ,,some,,info about accumeter VI. I want to build it because I looking to have one from more than two years...I have not enough money to buy a professional device ..Maybe for a expert people like many in this forum is not a problem...I'm just a begginer in electronics,in fact I've started now for the reason mentioned above... Ikumi does something more than a simple soldering ,I think.And if he is a japanese man(I supose )
he is very skilled ,and has a real PCB well done .Maybe he can help me with all information
I need .IKUMI if you want to give me a hand this is my email:
[email protected]
Or if you sell your device I will buy (I will make myself a gift for this Christmas)
Thanks
Alex

[Unregistered]

accu resistivity

In the forum there are only ,,some,,info about accumeter VI. I want to build it because I looking to have one from more than two years...I have not enough money to buy a professional device ..Maybe for a expert people like many in this forum is not a problem...I'm just a begginer in electronics,in fact I've started now for the reason mentioned above... Ikumi does something more than a simple soldering ,I think.And if he is a japanese man(I supose )
he is very skilled ,and has a real PCB well done .Maybe he can help me with all information
I need .IKUMI if you want to give me a hand this is my email:
[email protected]
Or if you sell your device I will buy (I will make myself a gift for this Christmas)
Thanks
Alex

hi alex,

in truth, im no expert either in geophysics and electronics, but i tried my very best to build one and understand how the circuitry works......it is a big advantage before you assemble the thing....here are some material you need...for accumeter VI pattern.

a 12 volt battery (mine is 7ah)
a battery charger
a 12 volt (input) power inverter (mine outputs 220vac)
a step-down transformer from 220vac to 24vac
a multimeter
a selector (rotary switch)
a push button switch....etc etc

ill try to post here some of my bill of materials and some pics... so that you can have a better idea.....

a piece of advice.....before you start building your resistivity project, try to understand first how it works, what are its capabilities and what are its drawback.....you might change your mind....anyway good luck........im now trying to manually log all my readings so that i can have a visual through a software....this is much better......

ill compile first all my things and post it here for others to see......i wanted to help....
g

[Unregistered]

capacitor and resistor value

hi carl,

in your previous post regarding diagram of accumeter VI, there is an equivalent circuit at the bottom....

for 24 vac, R= 130 ohms, C= 1,000mF@63VOLTS

how about for 220 vac?.....what will be the values for resistors and capacitors?......or can i remove the resistor and the capacitor from the circuit? what are the pros and cons? Need your help sir....thanks

[ikumi5]

50Hz or lower (square wave) Accumeter Frequency

Meter scale for Accumeter VI

[GeorgeGold]

Accumeter VI

Are you sure is 50Hz?
I don't think it is possible to work in Europe with 50 Hz because of possible interferences with the main power frequency already connected to ground point. How can we know this for sure? 50 Hz is OK for USA because main power is at 60 Hz. But if we want to use the accumeter in Europe I think we need an inverter at 60 Hz to avoid interferences and wrong mesurements. Did anybody really mesured the frequency and seen the shape of the signal?

[GeorgeGold]

If it really is 50 Hz square wave, than another question is what kind of square wave? is it all positive like pulse? Or it has also the negative side as AC ?

[GeorgeGold]

Hello Carl,
I look better to the circuit and could not understand the use of a polarized capacitor 200MF in a AC circuit. The AC will pass through ... no doubt.
Strange schematic.

Klaud,
If you mean the polarized capacitor 220uF / 63V - this one is ok, because it works in pulse positive voltage, you can see the dioda before it that cuts the negative

[GeorgeGold]

Carl, can you help me with this information?
Inverter frequency is 50Hz? Did you measure it?

I don’t think is 50 Hz because I read some specs form FLUKE Ground Rezistivity meters that says like this:

Measuring voltage: Um = 48 VAC (primary)
Measuring frequency: 128 Hz (125 Hz on request)
Noise current (Iext): max. Iext = 10 A (AC) (Ra < 20 Ù)
max. Iext = 2 A (AC) (Ra > 20 Ù)

Measuring principle: Current/voltage measurement
Measuring voltage: Um = 48 Vac.
Short-circuit current: > 50 mA
Measuring frequency: 128 Hz (125 Hz on request)
Probe resistance (Rs+ Res): max. 100 kÙ
Auxiliary earth electrode resistance
(Rh):max. 100 kÙ
Additional error from Rh and Rs: Rh[kÙ] �� Rs[kÙ/Ra[Ù] �� 0,2 %
Monitoring of Rs, and Rh with error indicator.

UM Measuring voltage limit 20/48 V
Earthing impedance (measuring frequency 55 Hz)

To ensure most feasible interference suppression during measurements, the
instrument is equipped with 4 measuring frequencies (94 Hz, 105 Hz,
111 Hz, 128 Hz),

Sorry for not getting back on this... I need to take some oscope measurements still, but basically the inverter output is a 24 volt p-p square wave. It is taken off some internal point of the power inverter.

Folks, please don't use a power inverter, and put 120vac on the probes! Very dangerous!

Also, the big cap is 1000uF @ 63v.

I'll try to make some time to finish the measurement, and post a formal schematic.

- Carl

[Carl-NC]

George,

It would be 50Hz or 60Hz, as it's just an ordinary power inverter. This is not a Fluke design and cannot be compared to a Fluke. It doesn't matter whether the waveform is all-positive or bipolar, the ground doesn't know the difference.

- Carl