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Problem with LCF meter

lynx

Member
Hi!

i did the LCF meter from EPE magazine feb/2004 but it's not working!!!
the only response i can get is when i regulate the contrast but only the
second line is vissible and it only shows dots! :( voltages to the 16F628 and to to the LCD display look ok 5V.

any help?
 

ericgibbs

Well-Known Member
Most Helpful Member
Hi!

i did the LCF meter from EPE magazine feb/2004 but it's not working!!!
the only response i can get is when i regulate the contrast but only the
second line is vissible and it only shows dots! :( voltages to the 16F628 and to to the LCD display look ok 5V.

any help?
hi,
That design does work OK, one of our members has made it.:)

Check that you have pin5 R/W pin connected to 0V.

Also re-check the wiring to the LCD.
 

mvs sarma

Well-Known Member
Hi!

i did the LCF meter from EPE magazine feb/2004 but it's not working!!!
the only response i can get is when i regulate the contrast but only the
second line is vissible and it only shows dots! :( voltages to the 16F628 and to to the LCD display look ok 5V.

any help?
you may rewire it for Phil Rice model of LC meter using a single 16F628A, it is working well. Google for LCmeter2 you get it . for frequency meter you can have another
 

lynx

Member
Congratulations,
You may also publish as to how you managed , to help others I suppose !!!
it's what Ericgibbs said... :)

now i got another problem!!!!!!!!!!!!!!!!!
while the L meter looks like it works ok! the capacitance meter it's not!!! it goes crazy showing various indications.

i don't know what's wrong with it.....
 

lynx

Member
guys any help?

the display constantly changes values when i'm measuring capacitors
there is no steady indication and also not close to the real value of the capacitor.

But when i turn it to inductor mode it measures fine... an 20uH inductor shows it is 23uH.
 

ericgibbs

Well-Known Member
Most Helpful Member

mvs sarma

Well-Known Member
guys any help?

the display constantly changes values when i'm measuring capacitors
there is no steady indication and also not close to the real value of the capacitor.

But when i turn it to inductor mode it measures fine... an 20uH inductor shows it is 23uH.
please indicated the exact components used by you, there was a suggesion to add 68pF cap
please search for LCF meter in edaboard.cpom
also there were some suggestions given long back one such is attached as txt file. please see.
 

Attachments

ericgibbs

Well-Known Member
Most Helpful Member

ericgibbs

Well-Known Member
Most Helpful Member
looks like the file is not available anymore.. can you tell us what changes you did?
hi,
For some reason its gone.?
I have found the *.asm so I will reassemble and post.:)
 

ericgibbs

Well-Known Member
Most Helpful Member
hi,
This zip file contains the LCFMET790_2 asm and hex files.:)
[for the 16F628A]
 

Attachments

svkghosh

New Member
hi ericgibbs:
I am working on the epe magazine lcf meter project recently using a pic16f628a. I'm not much acquainted with the programs, but I would like to know which pins of the pic are 'hi' and which pins are 'lo' after we turn on the circuit.My previous trials are showing 0v output from the pins 1,6,7,8,9,10,11,13(this means all the data ports and lcd ports are inactive). :confused:
 

ericgibbs

Well-Known Member
Most Helpful Member
hi ericgibbs:
I am working on the epe magazine lcf meter project recently using a pic16f628a. I'm not much acquainted with the programs, but I would like to know which pins of the pic are 'hi' and which pins are 'lo' after we turn on the circuit.My previous trials are showing 0v output from the pins 1,6,7,8,9,10,11,13(this means all the data ports and lcd ports are inactive). :confused:
hi,
Is the LCD display showing any characters when the program is running.?

If you are trying to measure with a Voltmeter the voltage on the pins of the PIC, you will not get a get a true High/Low reading, because the PIC to LCD pins are switching.

Give me some more details of the problem, I will try to help.
 
Last edited:

svkghosh

New Member
hi,
Is the LCD display showing any characters when the program is running.?

If you are trying to measure with a Voltmeter the voltage on the pins of the PIC, you will not get a get a true High/Low reading, because the PIC to LCD pins are switching.

Give me some more details of the problem, I will try to help.

Ok that is why I'm getting fluctuations in the data pin voltages!! The lcd display is not showing any output, I read your previous posts with 16F628 vs 16F628A maybe its the problem with the hex file so I downloaded the files for 16F628A (that I'm using) from your lcm.zip link. I simulated the complete circuit in proteas isis and I am getting a display of "CAPACITOR WAITING TIMING" and while connecting to the capacitor/inductor I'm not getting any value. Can you help me with the program and suggest what can be the possible reason for not having any display? :confused: :(
View attachment 63765View attachment 63765 xtal frequency: 3.27MHz
 

ericgibbs

Well-Known Member
Most Helpful Member
hi,
The 'cap waiting timing' indicates that the 628A is running OK.

Check RB6 input pin , you should see a square wave, try it both when in Cap and Ind mode selection.
 

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