Interfacing dc motor with microcontroller ic

[kwame]

Hi folks
I am interested in learning about how to forward,brake and reverse 12VDC permanent magnet linear actuators using microcontroller interfacing.
I want my linear actuator to reverse in opposite directions hourly or may every two hours;braking is not necessary as the linear actuator has inbuilt limit switches.
I am not familiar with programming in general,does anyone know of any already programmed that can do this job for me?

 

[john blue]

You can use H bridge to control it

 

[Reloadron]

Kwame, you have yet to provide a data sheet on this actuator. The actuator has what is known as a stroke, the stroke being the total distance it travels in or out. Then there is the time it takes the actuator to travel in or out. I assume you want the actuator to extend and stop. Then just sit extended for whatever time remains on the hour or two and then retract? That what you want?

If all of this is for an industrial project then you can consider commercial repeat cycle timers that are readily available off the shelf. You would use a commercial timer similar to these as an example.

If you want to run with a u controller then you would program the uC and have it drive an H bridge or the relay configuration well covered in this thread that you started.

Ron

 

[kwame]

Hi Johnny Blue
most H bridges i have seen have braking,which is not needed in my application.All i need is for the the actuator to forwarded and reversed.

 

[kwame]

Hi Ron
the permanent magnet linear actuator was ordered from china.It has stroke length of 12'' inches,12VDC,16mm/s.For full details for this link: http://www.runyn.com/index.php?main_page=product_info&cPath=1&products_id=6

 

[colin mac]

H-bridges proivde a brake function but you don't have to use it.

 

[john blue]

Instead of 4 h bridge control, tie the inputs to 2, then you will have only forward and reverse function

 

[Reloadron]

Looking at the specifications:

Specification:

Motor: 12V / 24V DC permanent magnet motor
Max. Push/Pull: 750N (165lbs)
Duty Cycle: 2min. working in 20min. (Max. 10%)
Speed: 10, 16, 20, 24, 29mm/s (0.39", 0.63", 0.79", 0.94", 1.14" per second)
Stroke: 300mm (12")
Limited Switch: Built-in (non-adjustable)
Installing Size: 405mm (16")
Protection Class: IP54
Operating Temperature: -20 ~ +65 °C

Looking at the specifications they do provide they don't tell us very much important stuff. It would be nice to know the full load and stall current. They mention "Limited Switch" but that is all they say. They don't mention N/O or N/C. Most applications have a limit switch at both ends of the stroke.

The duty cycle is only 10% but since you plan to extend, wait an hour and retract that should be OK. I just wish more data was provided on the thing.

Without knowing the current requirements it is hard to say how to drive it. Yes, it can be driven by an H bridge or reversing relay but the current draw needs to be known. Since it is obviously gear driven I would guess (purely a guess) the current will not exceed 5 amps under normal load use. The only option I see is to place it on a bench and test it measuring the current draw.

Again, you can buy a plug in commercial timer as I linked to, you can build a timer, or you can program (or have someone program a uC for your timing. You can drive it with a H bridge or relay.

Ron

 

[kwame]

Amps

Hi Ron
yes it is true that the current is not indicated at the website;i detected this two weeks ago, so.i contacted the supplier.To quote the supplier , ''Dear Sir,
The current is from 0.8 Amp ( no-load) to 4.8 Amp ( max-load) in theory; the max actual current should be less than 6 Amp''.

 

[kwame]

I am trying to build a simple H i sighted a few minutes ago online. This H bridge has received very good rating from the people to tried it.The schematic is at:https://www.pocketmagic.net/wp-content/uploads/2009/03/hbridge-radu1.jpg.
Can anyone explain what is meant by 'INPUT 1' and 'INPUT 2' stated in the schematic.This technology is virtually non existent in my country so folks,pardon my ignorance.

 

[kwame]

I am trying to build a simple H i sighted a few minutes ago online. This H bridge has received very good rating from the people who tried it.The schematic is at:https://www.pocketmagic.net/wp-content/uploads/2009/03/hbridge-radu1.jpg.
Can anyone explain what is meant by 'INPUT 1' and 'INPUT 2' stated in the schematic.This technology is virtually non existent in my country so folks,pardon my ignorance.

 

[kwame]

reversing contactor

Hi folks
i have just made a breakthrough in my research.I have come across what is known as 'reversing contactor' used for reversing ,single phase AC/DC motor and even three phase motors.
Does anybody have a working experience with the 'reversing contactors' per their modus operandi?

 

[kwame]

I think the reversing contactor must be more efficient than the general purpose DPDT miniature relays.It 1am(midnight) so i need to go to bed !Catch you t'row.

 

[Reloadron]

If input 1 is held high while input 2 is held low the motor will turn one direction. If input 1 is held low while input 2 is high the motor will turn in the opposite direction. If both inputs 1 & 2 are low the motor will be off. If inputs 1 & 2 are both held high then bad things happen. That is important! Inputs 1 and 2 can never, ever both be high or you basically short out your power supply.

With heat sinks on the transistors they are rated for about 10 amps so would handle a 6 amp load. Wow, my 5 amp guess was close.

While I did not look at the circuit in great detail it looks to be an everyday H bridge.

Ron

 

[kwame]

Thanks Ron!You are polymathic.Have you heard of reversing contactors and are you abreast of their modus operandi?

 

[Reloadron]

Kwame, in most cases a "contactor" is no more than a relay. By definition: A contactor is an electrically controlled switch used for switching a power circuit, similar to a relay except with higher current ratings. You don't need a contactor which brings up back to the relay circuits we have looked at. A reversing contactor is a reversing relay on steroids. It's just a relay with large contacts designed to handle high currents like hundreds of amps. I use large contactors at work for reversing high current motors and also for controlling high current pump motors as in a few hundred amps at 480 VAC. Again, a relay on steroids.

Ron

Hey, you were going to bed! Get offline! It is 10:30 PM here and soon I'll call it a day and go to bed.