Rotate shaft 4 times clock-wise and then 4 times anti-clock-wise
- Thread starter nimi79
- Start date
Dear THE_RB, thank you for guiding me.Sure, have a google for "pushbutton relay latch circuit".
Dear members, please find attached a circuit design that is a combination of Latching Relay and Back-and-Forth Robot.
As per description given in the articles, latching relay (dashed rectangle in attached circuit design) will be activated once we press-and-release NO SW (normally-open switch, part of latching-relay). This will power IC IXDI604 and assume that, motor will start rotating clock-wise. It will keep rotating clock-wise till I press-and-release REV switch (miniature snap-action switch). Now motor will reverse the direction of rotation and will start rotating in anti-clock-wise direction. It will now keep rotating anti-clock-wise till I press-and-release FWD switch (miniature snap-action switch). It will again change the direction of rotation and start rotating in clock-wise direction. Press-and-release action of REV and FWD switches, alternately, can be repeated any number of times till we press-and-release NC SW (normally-close switch, part of latching-relay). It will finally stop the motor.
Motor will be a 12V DC, standard, 300 RPM motor.
Please verify if the design of the attached circuit is correct or not. Also verify if the explanation given above for the attached circuit is correct or not.
Am I missing any component in the attached circuit? Does this circuit need any additional component for safety?
As per description given in the articles, latching relay (dashed rectangle in attached circuit design) will be activated once we press-and-release NO SW (normally-open switch, part of latching-relay). This will power IC IXDI604 and assume that, motor will start rotating clock-wise. It will keep rotating clock-wise till I press-and-release REV switch (miniature snap-action switch). Now motor will reverse the direction of rotation and will start rotating in anti-clock-wise direction. It will now keep rotating anti-clock-wise till I press-and-release FWD switch (miniature snap-action switch). It will again change the direction of rotation and start rotating in clock-wise direction. Press-and-release action of REV and FWD switches, alternately, can be repeated any number of times till we press-and-release NC SW (normally-close switch, part of latching-relay). It will finally stop the motor.
Motor will be a 12V DC, standard, 300 RPM motor.
Please verify if the design of the attached circuit is correct or not. Also verify if the explanation given above for the attached circuit is correct or not.
Am I missing any component in the attached circuit? Does this circuit need any additional component for safety?
Attachments
Your latching relay with two pushbuttons looks fine.
I have no experience with that hbridge chip, but at first glance it looks ok as the hbridge outputs keep it's inputs "latched", and the buttons will reverse it.
That all looks ok. The final problem you have is that reversing the voltage to a running DC motor makes a huge current overload, much worse than a short circuit.
A good way to solve that is to run the motor power through a current limiter (like a simple LM317 constant current circuit). That will fix the current overload on reversing, but will cause problems for your hbridge IC as it uses the same Vcc pin for motor power and it's internal logic power.
If you used another relay instead of the hbridge IC that would be fine, and you could use the constant current limiter.
Or if you are fixed on using that hbridge IC, the best you can do for current limiting is to just put a resistor in series with the motor itself. That won't be as good as proper current limiting but will still provide some limiting of the reversing fault current.
I have no experience with that hbridge chip, but at first glance it looks ok as the hbridge outputs keep it's inputs "latched", and the buttons will reverse it.
That all looks ok. The final problem you have is that reversing the voltage to a running DC motor makes a huge current overload, much worse than a short circuit.
A good way to solve that is to run the motor power through a current limiter (like a simple LM317 constant current circuit). That will fix the current overload on reversing, but will cause problems for your hbridge IC as it uses the same Vcc pin for motor power and it's internal logic power.
If you used another relay instead of the hbridge IC that would be fine, and you could use the constant current limiter.
Or if you are fixed on using that hbridge IC, the best you can do for current limiting is to just put a resistor in series with the motor itself. That won't be as good as proper current limiting but will still provide some limiting of the reversing fault current.
Dear THE_RB, thank you for your feedback. Can you please suggest me the type of other relay you have mentioned in the post above?Your latching relay with two pushbuttons looks fine.
I have no experience with that hbridge chip, but at first glance it looks ok as the hbridge outputs keep it's inputs "latched", and the buttons will reverse it.
That all looks ok. The final problem you have is that reversing the voltage to a running DC motor makes a huge current overload, much worse than a short circuit.
A good way to solve that is to run the motor power through a current limiter (like a simple LM317 constant current circuit). That will fix the current overload on reversing, but will cause problems for your hbridge IC as it uses the same Vcc pin for motor power and it's internal logic power.
If you used another relay instead of the hbridge IC that would be fine, and you could use the constant current limiter.
Or if you are fixed on using that hbridge IC, the best you can do for current limiting is to just put a resistor in series with the motor itself. That won't be as good as proper current limiting but will still provide some limiting of the reversing fault current.
I was just browsing other threads on this site and came across this thread. Even you have commented on that thread
. Can you suggest if this circuit (post#5 by KMoffett) can help me out achieving what I was looking for?A "reversing relay" is usually a DPDT type, functionally it is similar to the hbridge IC. It changes the polarity of the two DC motor wires.
KMoffett's circuit adds a time delay, which can help. Personally I prefer a constant current limit as it does not need the time delay, and will provide a gentle acceleration and deceleration of the motor, and also increase the life of the relay contacts.
KMoffett's circuit adds a time delay, which can help. Personally I prefer a constant current limit as it does not need the time delay, and will provide a gentle acceleration and deceleration of the motor, and also increase the life of the relay contacts.
Unless this is a school/learning type project there is a easier and better way to do it. No switches or relays needed or reversing of the motor. Using a crank and connecting rod or a 'scotch yoke' would move the object back and forth with no electronics involved.
Yeah that's true, we still know nothing about the OP's machine or what it does.
A crank is ok for small stuff, but mostly where you see this type of back-forth linear machinery is on production lines for spraying paint or coatings, and the linear track length might be a couple of yards or more.
A crank is ok for small stuff, but mostly where you see this type of back-forth linear machinery is on production lines for spraying paint or coatings, and the linear track length might be a couple of yards or more.
