LCF Meter using PIC16f628

[aswinthomas]

+lc +meter +16f88

hi all
my lcf is working , using crystal 3.2767Mhz but it has no accuracy can any one help me

 

[MAKAR]

l meter pic16f

I have build the EPE LCF meter too(I use PIC16F628A).But I have the same problem - when I turn on this device "CAPACITOR TIME OUT" apears at the display.And if I connect any capacitor(1uF or higher) at this time to the crocodiles(frequency of internal generator is slow down), "CAPACITOR TIME OUT" is disapear from display and LCF meter run to works normaly with high accuracy at all ranges.

 

[gianky69]

lcf meter wsad

Try this fix (it works fine for me).
Open source code and go to "CAPACITOR" section and add a clrf ZERO statement after "call COPY_TIME_REGA":

CAPACITOR movlw B'00000010' ; set for correct osc
movwf PORTA

clrf TIMEMSB
call INDTIMER

call COPY_TIME_REGA
clrf ZERO ; fix capacitor timeout problem
clrf POINT
clrf LARGE

I have also done the same mod in INDUCT section in the same position, but I think that is not needed.


If it doesn't work you can try to reduce R5 from 10k to 4k7.


Bye
Giancarlo

 

[MAKAR]

прошивка lcf-meter

Thanks.What compilator are you use to make HEX file? I'am alredy try to reduce R5 from 10k to 1k it desn't work.
Best regards, Makar.

 

[gianky69]

epemag.com

I've used MPLAB IDE v7.31 from Microchip and IC-Prog 1.05E with Propic2 programmer.
I've attached a compressed file with:
.ASM file (source code)
.INC file
.HEX file (compiled and ready to be used with programmer)
The source code was translated from TASM to MPASM with Toolkit "TK3".

I hope that this fixed version for PIC16F628A will be ok for you too.

Giancarlo

 

[MAKAR]

16f628a lc meter

Thank you very much for the help! I hope I'm programm my PIC at the next week(I haven't programmer) when I'm go to work.

 

[Sandokan]

schematic lcf meter with pic16f628

Here my pcb for this proyect

 

[paul_costin]

Re: schematic lcf meter with pic16f628

Does someone has the circuit draw in Proteus? I`m a beginner in electronics, and I would like to try this project. And if someone has the source code in C, not .asm, and would like to help me... Thank you

 

[luxornet]

I tried LCF meter capacitor.
At start, with no capacitor connected, the frequency is approximately 330.000Hz and 987pF displayed on second line.
If I measure a capacitor value seems to look pretty good (I did not calibration) but when I remove that capacitor or press the SET, either of the two actions makes them aces, the display shows a frequency of over 15MHz and displayed 2-3 pF value of the bottom row.
I changed the resistance R5 4.7Ko but without success. I shorted R5 and then all phenomena gone but the display frequency is different than that which could be measured with the meter at the entrance CLK/RB6 (pin 12).
I used only indicated components, HEF4011BP, PIC12F628 (not A) ...
Do you have any idea how to solve the problem?
Thank you.

 

[hugo2009]

Hi.
I assembled epe lcf meter,but I have a problem in inductance mode.
I had no chance to obtain exact inductor's value.
Trimmer VR2 is set to 0 ohm.I shorted the probes,pressed null-button and then I placed 47uH inductor.
I obtain only 44uH.If I place 330uH I obtain 311uH.
With VR2 turned on the other side,value is less(37uH for 47uH).
What's the problem?
Thanks and regards!

 

[luxornet]

If you find helpfully, maybe you visit this page, where all steps for making the LCF Meter are explained.

**broken link removed**