7 segment decoder

[koolguy]

I just use 3 4.7K to 24V
so, across 4.7 k it was 8V.
the input to CD4511 is not fine it make all logic to 8 when original 12V of CD4511 is taken it work fine 4 in display, why this is happening?

 

[koolguy]

The main points to know how to use 24V logic to work in 12V.

 

[ChrisP58]

If pin 16 of the 4511 is at 12v, 5.1v won't be high enough to be seen as a one on the logic inputs. The datasheet lists Vih min for 10v at 7v, so you'll probably need 8v to be sure. And 10v to 12v will be just great.

But the outputs of the 4511 are logic high when a segment is lit. So the other end of the LED through the limiting resistor needs to go to ground. The schematic you post in #59 has them going to +12V

 

[koolguy]

If pin 16 of the 4511 is at 12v, 5.1v won't be high enough to be seen as a one on the logic inputs. The datasheet lists Vih min for 10v at 7v, so you'll probably need 8v to be sure. And 10v to 12v will be just great.

But the outputs of the 4511 are logic high when a segment is lit. So the other end of the LED through the limiting resistor needs to go to ground. The schematic you post in #59 has them going to +12V

The main points to know how to use 24V logic to work in 12V.

 

[ChrisP58]

What type of outputs do you have on your PLC? Are they high/low driven? Or are they open collector (driven low/floating high?)

The answer to that question can make a big difference in how you interface to it.

 

[koolguy]

If you want to use 24v and 12v use zener diodes on the inputs... If you use a 2k2 resistor with a 5v1 zener then it should work with 24v input and 12v input..

Is thee any technical difference?

24V → 12K(up)+10K(down) → CD4511 → (another pin 0f 10K to GND) common pin of voltage divider output 10.9V

 

[Ian Rogers]

I'm leaving this thread now as I have no idea whats required... I seem to be ill-advising so best if I jib out!!

 

[koolguy]

I'm leaving this thread now as I have no idea whats required

The idea is the CD4511 is to be used to display BCD from PLC

 

[ChrisP58]

The idea is the CD4511 is to be used to display BCD from PLC

So that we know what the PLC source really looks like, please answer my question from post #65.

 

[KeepItSimpleStupid]

1. OK, What does the PLC supply as logic signals? 24 and 0V? Open collector?

 

[koolguy]

What type of outputs do you have on your PLC? Are they high/low driven? Or are they open collector (driven low/floating high?)

The answer to that question can make a big difference in how you interface to it.

Hello,
I will post the info of PLC , but before this it is to be know how drive cd4511 from 24v?

 

[koolguy]

OK, i got it!
Operating voltage 24v
PLC mitusbhi 202hcpu
Output card qy41 cards 32 bits
ladder programming

 

[koolguy]

Hello,
I think the problem is solved.
Just know there was 24 transformer with rectifier 4 Diode!
it give 24V DC it was without any capacitor when i place small 22uF.
It gives around 34V. so i placed 4.7K 4 series i get 8V and both supply 37V and 12V gnd as common.
after this the BCD from 24V was succesful.
I got the importance of C in Rectifiers.
but what was the problem which was there due to absence of C 22uF the riple in CD4511 input?

 

[KeepItSimpleStupid]

Koolguy: your "best practices" techniques are borderline. i.e If you don't have time to do it right, when will you have time to do it over?" This was one of the hardest to floow threads I have seen. Part do to language. Part due to incomplete specs or overall final desired outcome.

This is going to be a remembered thread for the wrong reasons. I almost bailed out too.

 

[KeepItSimpleStupid]

You could have gotten this https://www.eevblog.com/forum/proje...-to-5vdc-how-decent-is-my-solution/?topicseen for an answer.

But apparently, it uses way more components than your budget would allow.

 

[Tony Stewart]

If you want to adapt your working 5V 7447 design for 12V just use a suitable power heatsink & 5V reg and accept the heat loss. such as 78R05 which has a 0.5V drop max for using 9V batt backup. down to 6V

 

[koolguy]

Thanks

 

[KeepItSimpleStupid]

I have this motto: if I fix it, I don't ever want to see the same problem again. If I build it, I don't want to fix it. Sometimes I goof and the cost is on me.

 

[koolguy]

Sometimes I goof (mistake) and the cost is on me.

mean

 

[KeepItSimpleStupid]

yep, mistake. I did a walkway. I didn't know about the styrofoam underlayment and I just used rock and lawn fabric. Not sure if there is a problem with the implementation, but I might have more weeds between the slabs than I'd like.
But, I used edging instead of the proper corner like secured bracing, so over winter, the edging moves up from the ground. Now, it's actually broken from banging it back in.
That I have to fix and it probably means do it over.