Counter 74193

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Haidy

New Member
Hello
my project is simple but infact im still a beginner
in first year
my project is Shaft Encoder
anyway
i connected the counter 74193 in my circuit
the clock input to the counter is the opto coupler output
but the counter is counting nonsense
it counts 1 5 7 1 5 7 13 just like that
so plzzzzzzzzz any one tell me what to do to make it count right, from 1 to 16 in binary
waiting from u all
thanx
bye
 
Did you install a bypass capacitor?

Logic circuits need a 100 nF capacitor between the Vcc and gnd pins, ie. usually pins 14 & 7 for a 14 pin IC and pins 16 & 8 for a 16 pin. One for each IC.

If you don't have adequate bypassing, you will see strange effects due to coupling through the supply line.

Another possibility is the rise and fall times of the clock signal. If they are too slow, it may not count properly. See the dtat sheet for the 74193.
 
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You may need a pull up resistor too, not sure if that one counts on the negative pulse flank, but for a 5 Volts DC supply 2k2 Ohms is usually adequate.
 
will the 2.2K resistor b connected in sereis with the 100nF capacitor btween vcc & ground??
also,,
the rise & fall not too slow
im using a motor of speed 30/36,, which rotates the disc & causes pulse
is that slow???
plz tell me
thanx
 
You may need to clean up the output of the optocoupler with a comparator to get good quick, clean, hi-lo transitions. I experienced similar problems with a modified mouse project and a comparator was the solution.
 
Haidy said:
will the 2.2K resistor b connected in sereis with the 100nF capacitor btween vcc & ground??
also,,
the rise & fall not too slow
im using a motor of speed 30/36,, which rotates the disc & causes pulse
is that slow???
plz tell me
thanx
Click to expand...
No, the pullup resistor is required on the output of the opto-isolator because it is an open collector output. It should go from the the output of the opto-isolator to the Vcc supply. You should look at the output of just the opto-isolator with a scope. When that signal looks the way it should then you can attach the counter. You also should post a schematic, since providing meaninful help is more difficult without one. The schematic needs to contain part numbers and values. Don't waste your time doing this in 'Paint' or 'Draw' or a word processor.
 
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Make sure your LOAD Pin #11 & CLEAR Pin #14 are tied to Ground. Make sure whatever Pin (COUNT UP or COUNT DOWN) that you ARE NOT using for the clock input is tied to +5v. Also you may want to put a schmidt trigger IC between th opto and the clock input on the 74193, i've seen sensing disks on motors put out what looks like a distorted sine wave.
 
what about the comparator??

agent420 said:
You may need to clean up the output of the optocoupler with a comparator to get good quick, clean, hi-lo transitions. I experienced similar problems with a modified mouse project and a comparator was the solution.
Click to expand...


Hello sir
thanx so much for telling me about the comparator
first i couldnt understand what's it!
but i thought it maybe a timer 555
am i right??
but unfortunately i couldnt ffind it's data sheet
so plz if u have any connection for it plz send it to me
coz i need to know how exactly will i use it in my circuit
would u plz reply me as soon as u can>???
thank u so much sir
& thank u all
bye
 
well
so what's the " schmidt trigger IC" ?
& sorry, what do u mean exactly by " btween opto coupler & clock input" ??
also
my load is connected to high vcc not to ground
i got it from the datasheet
& when i connected load to gnd it gave out nothing
plz answer me & comment
thanx
 
schmitt trigger

Hello
well
just now i found that schmitt trigger u told me about
it's a timer 555
well
it's ok now
but i still have question
when i will connect the timer 555 to the output of my opto coupler
the clock pulses input to the counter will b depending on the 555 & not on the opto coupler & this contradicts the idea of my project
which depends on counting the pulses due to motor rotation
well,, am i right or wrong??
plz tell me

thank u
bye
 
um, I didn't see if you tried a pull-up resistor on the phototransistor's output. There's a good chance that's all that's needed. This is an example of how that works. add the 10K [edit: resistor, not transistor] and take the output from the collector of the PT.

**broken link removed**
 
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I would not normally use a 555 as a Schmitt Trigger (In fact I've rarely ever used a 555; there is usually a better alternative). There are ST packages available such as the 74LS14, 74C14 74HC14, 40106 etc.
 
Re:

Hello
i used " monostable timer 555"
but the counter still giving nonsense
it's not counting right at alllllllll
i used the pull up resistor
& no change
tell me what to do!!!!
nothing at all is working with me
im working in a right way but just i need the counter to count right
wish anyone can give more help
thanx u all
bye
 
Post your circuit so we can see what you have done. It is difficult to comment without knowing exactly what you have built.
 
How circuit diagram??

Hello
u asked me to send the circuit diagram
but how can i send a circuit diagram that is not working with me?!!!!
i dont know it's right or wrong, so...
on what basis will i send it?!!!!
 
The reason I asked you to post your circuit is because it does not work; this is so we can advise you as to how to make it work.
 
hi
in ic 74193, if i want to count down, how do i make?
i have its catalog but it is only a small picture.
i can't do that.
 
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