Phasemeter for perfect coils

[boilcoil]

It can be simulated by Proteus:


The osciloscope lines are not so corect, because simulator play 4069 like step invertor (comparator) only, but two input invertors works as analog amplifiers.

[dbanner]

Yes, circuit is from last century, but so am I.
I plan to build original circuit, if it works satisfactorily then it will be incorporated into a device which also measures AC millivolts accurately up to a frequency of 20khz.
This device will also have outputs for oscilloscope to be connected, but can be used as stand alone device for coil balancing. It will also contain a universal coil tester oscillator.
Finally, an all-in-one device.
No need for re-inventing of wheel. If it works, I use it, that way you give tribute to original author of circuit.

[dbanner]

Here is another very interesting circuit for a phase meter. This one boasts of an accuracy 0.1 degrees up to 100khz. The input signals need to be square waves, but that's no problem really, they can be easily squared up when dealing with sinus at below 20khz.

[ivconic]

Finished yesterday.
Works quite alright from a start.
No mistakes on pcb.
Nobody commented yet (obviously low interest), but i added TX&RX frontends on pcb, to be able to experiment with only coils.
In order to examine and experiment with only a coil; RX coil should be connected to RX input of RX frontend based on MCP601 (+5v supply, later planned to adapt this for Arduino).
RX output goes, obviously, to one of the phasemeter inputs.
TX coil is connected to TX output (common one, from White's Classic, SMW etc) and TX "hot" also connected to another phasemeter input.
I used LM317 with purpose. To be able to adjust and lower the main supply voltage down to 8.4V (later planed for 2x18650 Lipo-s).
I haven't tried with analog scale. I attached only voltmeter. Later i am planning to attach there Arduino and probably OLED or any similar GLCD.
It works alright. Voltage rise or drops relating to "detection" and type of target. Until i write code for Arduino and make precise phasemeter indication.
I also left several pins for jumpers.
Definitely those must be jumped. Pin 1. at LM311 must go to ground and output must be pulled up with suggested resistors. (rolling rock's post above, quite correct)
I used Bounty Hunter 10" coil to experiment with. No parallel or in series capacitor added. Because coil is having some capacitance inside.
Frequency is exactly 6.5kHz. With 100ohms trimmer i can rise amplitude to 64vpp !!! (or oscilloscope is broken and displays false readings)
I put MPF102 fets. So far so good.
TX output transistor is BC327/40, driven by BC550. The rest of transistors all are also BC550.

[walkman]

[QUOTE = ivconic; 259324] D?n bitti .
Baştan beri olduk?a iyi ?alışıyor.
Pcb ?zerinde hata yok.
Hen?z kimse yorum yapmadı (belli ki d?ş?k ilgi g?rd?), ancak sadece rulolarla deneme yapabilmek i?in pcb ?zerinde TX&RX ?n u?larını ekledim.
Sadece bir bobini incelemek ve denemek i?in; RX bobini, MCP601'e dayanan RX ?n ucunun RX girişine bağlanmalıdır (daha sonra Arduino i?in uyarlanması planlanan +5V besleme).
RX ?ıkışı, a?ık?a, fazeter girişlerinden birine gider.
TX bobini TX ?ıkışına (White'ın Classic, SMW vb. Ortak olan) ?ıkışına ve ayrıca başka bir fazeter girişine bağlı olan TX "hot" (sıcak) bağlanır.
Ama? olarak LM317 kullandım. Ana besleme voltajını 8,4V'a (daha sonra 2x18650 Lipo-s i?in planlanmış) ayarlayıp d?ş?rmek.
Analog skala ile hi? denemedim. Sadece voltmetre ekledim. Daha sonra orada Arduino ve muhtemelen OLED veya benzer herhangi bir GLCD takmayı planlıyorum.
İyi ?alışıyor. "Algılama" ve hedef t?r?ne bağlı olarak voltaj y?kselmesi veya d?şmesi. Arduino i?in kod yazana ve kesin faz?l?er g?stergesine kadar.
Ayrıca jumperlar i?in birka? iğne bıraktım.
Kesinlikle bunlar atlanmalı. LM311'deki pim 1. toprağa gitmeli ve ?ıkış ?nerilen diren?lerle ?ıkarılmalıdır. (kayanın ?st?nde, olduk?a doğru)
Denemek i?in Bounty Hunter 10 "bobini kullandım. Paralel veya seri kapasit?r eklenmedi. Bobin i?inde bir kapasitans var.
Frekans tam olarak 6.5kHz'dir. 100ohms d?zeltici ile ben 64vpp genlik artırabilir !!! (veya osiloskop kırılmış ve yanlış okumalar g?steriyor)
MPF102 fets koydum. ?ok uzak ?ok iyi.
TX ?ıkış transist?r? BC550 tarafından s?r?len BC327 / 40'dır. Transist?rlerin geri kalanı da BC550'dir.



[ATTACH] 46972 [/ ATTACH]
[ATTACH] 46973 [/ ATTACH] [/ QUOTE]

[ivconic]

Workaround...

[ivconic]

Fail No 1.
********
Tried with Oled and Arduino Nano. Simple analog read.
First; too much noise. I have to rearrange wires and short them as much as possible, between phasemeter and analog input.
Second; i can get steady "scale move and stay at position" kinda behavior.
It behaves "binary". It jumps and returns back if i come with "target" across the coil.
Only if i carefully pick a spot on coils surface and leave the "target" there; scale stays to some position, along with constant trembling around.
I tried it first via RX frontend and MCP610, than i tried it without (RX coil directly to phasemeter input); no differences. Same behavior.
Obviously this will not do.
First i will probably have to try it with real analog scale and see the behavior. And than later to try to implement Arduino+OLED.
***
I have added 4k7 + 100nF (in parallel) from A0 to gnd. Than 10k from A0 to phasemeter output. Common voltage divider.
Also i added heavy filter in code, for analog reading.
None progress.
But that's only related to stability of readings.
That's easy part of a job.
More difficult part would be to dig out why this is behaving so binary?

[Nandor]

enjoyed reading and watching! As always!

[ivconic]

Thanks Nandor!
Arduino Nano was wrong choice at this moment, because i soldered voltage divider too close to Atmega, hanging just above it, so analog input is picking up too much noise.
I tried with old analog scale and everything comes to its place. No "jumps" in readings.
What's next now?
Calibration, proper calibration of scale (analog or digital, the same, needs calibration).
So i have found interesting solution and yet simplest possible.

[dbanner]

So the circuit works, very good. What was worrying to me is level of Rx signal(millivolts) directly from coil. However reading the text, I realized that the circuit works at zero crossing of waveform, so no problems with small amplitude vs larger peak to peak of TX.
Ivca, can you say where is 360 degrees on analog scale. Would it be at full scale deflection or would full scale deflection be calibrated to 0 degrees?
I haven't built it as yet. Was looking for a good AC millivolts adapter to work in conjunction with phase meter to measure residual voltage of RX when coil is nulled to the required residual phase shift. I found this nice circuit in a French magazine. It has a wide bandwitdth and high input impedance. Just what is required to measure ac sinus in the khz range.

[dbanner]

Here is yet another interesting circuit. A phasemeter adapter for Digital voltmeter. This one comes with a very nice pcb layout.

[ivconic]

So the circuit works, very good. What was worrying to me is level of Rx signal(millivolts) directly from coil. However reading the text, I realized that the circuit works at zero crossing of waveform, so no problems with small amplitude vs larger peak to peak of TX.
Ivca, can you say where is 360 degrees on analog scale. Would it be at full scale deflection or would full scale deflection be calibrated to 0 degrees?
I haven't built it as yet. Was looking for a good AC millivolts adapter to work in conjunction with phase meter to measure residual voltage of RX when coil is nulled to the required residual phase shift. I found this nice circuit in a French magazine. It has a wide bandwitdth and high input impedance. Just what is required to measure ac sinus in the khz range.

Can't tell for sure yet.
Haven't find proper scale.
In meantime trying to fix the code for Arduino.
On Davor's suggestion i replaced 5V6 zener diode with 1uF capactor and got somewhat better and stable output.
Also; the RX frontend i added on pcb is affecting the phase, so i'll have to wire RX coil directly to phasemeter input, bypassing the RX frontend, in order to calibrate it properly.

[daluka]

Dbaner, check projects in Elektor. A calibration procedure is described for each, this is not the case with your scheme.

[dbanner]

Hey, thanks for posting those. Looks very interesting. I'll download the files and have a closer look.
My soldering iron finally gave up. Can't find replacement tip. Bummer. Now I'll have to purchase a new bloody iron.
I'm having a cold beverage at the moment. I love Sundays. A mild 23 degrees Celsius here in Trinidad.
To all the forum members out there, hi fives.