H-Bridge

spec · Mar 23, 2016

kal.a said:
Another issue is that the output of the PLC is 24V+ for pulse and the logic gates input have a maximum of 7V+. So I will have to modify the circuit with a transistor circuit similar to what you had in the original design on post #25.

You are quite right about 24V being too high for a 74 series logic gate input, but if you post details of the PLC output it should be possible to do a simple interface.

kal.a said:
(not to mention that I still can't get the gates to work )

Logic chips are the way to go- simpler and faster. The logic circuit is very simple and should not cause you any problems?

spec

spec · Mar 23, 2016

kal.a said:
I'm sure I said this before but this stuff is surprisingly fun

Cheers
Kal

That is good. It will be even more fun when you are familiar with the basic principals/techniques and can concentrate on inventing new applications. The way you are going it wont be long before things will suddenly click into place. Just keep thinking and investigating. One thing though is that no one knows everything about a particular field, even the most experienced, and it is best to focus on one area and get that under your belt before moving on to a new area.

spec

kal.a · Mar 23, 2016

spec said:
Hy kal,

Like you, I can't understand what that spec chap was on about. Your circuit is correct.

Hey, watch it there that's my mentor you're talking about

spec said:
It is good that you are considering the dissipation of the voltage regulator, as you should for every component in your circuit. But you are not right in thinking that the motor current passes through the voltage regulator though. So it makes no difference to the voltage regulator what current any motor that you drive with the H bridge. The voltage regulator even has the same dissipation if no motor is fitted.

Thanks spec, that was a momentary lapse of reason as I'm also working on the power supply for the motor and confused the two.

I'm going to try my logic gate again the next couple of days as I will have more time to experiment with them and hope to have some gains in that regard.
I will try adding to your circuit to interface the PLC and then post it with the PLC wiring diagram for you to review it and grade my progress

Thanks so much spec.
Have a wonderful evening!

spec · Mar 23, 2016

kal.a said:
Hey, watch it there that's my mentor you're talking about

Thanks spec, that was a momentary lapse of reason as I'm also working on the power supply for the motor and confused the two.

I'm going to try my logic gate again the next couple of days as I will have more time to experiment with them and hope to have some gains in that regard.
I will try adding to your circuit to interface the PLC and then post it with the PLC wiring diagram for you to review it and grade my progress

Thanks so much spec.
Have a wonderful evening!

No probs kal,
Nice to see someone progressing so well. It is a great shame you are not in a design and development lab with a mentor. Apart from study, that was the thing that helped me the most. You can't beat working with people at the coal face. It is the same in all disciplines whether it is learning a foreign language, playing a musical instrument, or doing brain surgery.

For my part, I have learnt an awful lot from ETO, both by researching components/techniques to prepare submissions, and also by just reading the many posts about the wide range of subjects on the site.

Cheers

spec

kal.a · Mar 27, 2016

Hi spec,

Hope you're having a great Easter holiday.

I finally got my sn74LS00N to work and somehow without any difficulty at all!
I put together a few different versions of the circuit as follows: (the pin numbers on the gate are different on the schematic are different from my gate)

**broken link removed** Just added transistors to your last circuit and used with an addition of a voltage regulator to supply the 5V+
**broken link removed** I modified the logic gate so I can minimize the number of transistors I will be using. ( I wired this one on my bread board and it worked well LEDs on the Opto's receiver)
**broken link removed** Although I like Version 2 I am not sure it's wise to connect the PLC's ground to the H-Bridge control circuit so I added optocouplers. I'm guessing that will make this version a bit slower but I like the isolation aspect of it.

I'm also wondering if adding 10K pull down resistors to the base of QN1 and QN2 would be a good idea to pull the base down and leave them floating when the PLC lines are not active.

Cheers
Kal

spec · Mar 27, 2016

kal.a said:
Hi spec,

Hope you're having a great Easter holiday.

I finally got my sn74LS00N to work and somehow without any difficulty at all!
I put together a few different versions of the circuit as follows: (the pin numbers on the gate are different on the schematic are different from my gate)

**broken link removed** Just added transistors to your last circuit and used with an addition of a voltage regulator to supply the 5V+
**broken link removed** I modified the logic gate so I can minimize the number of transistors I will be using. ( I wired this one on my bread board and it worked well LEDs on the Opto's receiver)
**broken link removed** Although I like Version 2 I am not sure it's wise to connect the PLC's ground to the H-Bridge control circuit so I added optocouplers. I'm guessing that will make this version a bit slower but I like the isolation aspect of it.

I'm also wondering if adding 10K pull down resistors to the base of QN1 and QN2 would be a good idea to pull the base down and leave them floating when the PLC lines are not active.

Cheers
Kal

Hy kal,

Hope you are enjoying the Easter break too.

My missus is down with flu at the moment so I am having to do some domestic things which doesn't gel to well with me; I even had to do the shopping yesterday. Still I managed to snuggle in a four pak of doughnuts and ate the lot in one go.

Glad you got the 74LS logic circuit working. 74LS is fairly well behaved stuff.

I like your circuit two. You do know that the two input lines will be NOT Direction and NOT pulse. Still, I expect you can handle the inversion in software.

Good bit of engineering about the 10K resistors from the input transistor bases to 0V. It will make the circuit more immune to noise when the PLC outputs go high impedance.

I am surprised that the PLC runs off a 12V supply line. Do you have a specification/description/part number for it?

Cheers

spec

kal.a · Mar 27, 2016

Hi spec,
I heard you guys were had some fun with storm Katie.....

The PLC runs off 24V+ and put out 24V+ pulse signal. It's a huge Manual to post but here's a **broken link removed**of the wiring of inputs and outputs.
What do you mean NOT direction and NOT pulse?
Booth optos are off when pulse is off
When pulse is high and direction is low, X1 is on
When pulse is high and direction is high, X2 is on

Kal

spec · Mar 27, 2016

kal.a said:
Hi spec,
I heard you guys were had some fun with storm Katie.....

The PLC runs off 24V+ and put out 24V+ pulse signal. It's a huge Manual to post but here's a **broken link removed**of the wiring of inputs and outputs.
What do you mean NOT direction and NOT pulse?
Booth optos are off when pulse is off
When pulse is high and direction is low, X1 is on
When pulse is high and direction is high, X2 is on

Kal

Hi kal,

Thanks for picture of PLC. It looks like quite a beast
About the NOT inputs- I told you that spec chap talks bollocks.
When you have the time, I have a few circuits which need sorting- perhaps you could help.

Cheers

spec

PS Storm Katie didn't touch us too much- just four hours of high winds and squalls. Some parts of the UK got hit pretty bad though.

kal.a · Mar 27, 2016

Take a bow spec, I haven't learned so much for a long time and I never thought I could.
I mean this with all sincerity, if you have the time, your talent for teaching could change some people's lives. Literally.
And this forum again was not at all what I expected. I never expected such an unbelievable level of knowledge (brilliance at the matter of fact) and willingness to help.
I browse the forums every now and then and read some topics that attract my attention and I often shake my head in awe and wonder " how did they get to be so smart"

Enjoy the rest of you holiday and wish the missus a speedy recovery.

Cheers
Kal

spec · Mar 30, 2016

kal.a said:
Take a bow spec, I haven't learned so much for a long time and I never thought I could.
I mean this with all sincerity, if you have the time, your talent for teaching could change some people's lives. Literally.
And this forum again was not at all what I expected. I never expected such an unbelievable level of knowledge (brilliance at the matter of fact) and willingness to help.
I browse the forums every now and then and read some topics that attract my attention and I often shake my head in awe and wonder " how did they get to be so smart"

Enjoy the rest of you holiday and wish the missus a speedy recovery.

Cheers
Kal

That's very kind of you Kal.
Like you, I am amazed at the things that the ETO members know.
Perhaps quite soon you will be helping others on ETO yourself- once you get a few basics under your belt as you have done quite quickly, your knowledge will grow exponentially and you will be surprised how much you will learn. The big secret is to boil things down to the basics and also to be logical.

Thanks for your Easter wishes- but afraid that both my wife and I have now got some kind of bug. Still I hope you had a good Easter

All the best

spec

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