internals of a control module for 12vdc power steps

[downtowndarrel]

looking for any info on this 12vdc control module. consists of a dc reversing circuit, limit in, limit out.
**broken link removed**
**broken link removed**
**broken link removed**

 

[KeepItSimpleStupid]

When searching, I found this: https://www.rvweb.net/tech_lib/Quickee.html

Strange little gizmo. Somewhere searching, someone said rebuilds can be had for $75, but I saw prices like $200.
One model is not repairable and the mechanism is from a Ford Tauris which is also made by Doorman.

Not sure what your intent is? Repairing or making something to replace it.

I saw references to different safety modes depending on the controller and the possibility of a reversing relay, bypass relay and probably a NOT enable relay. The relays would be the weakest link. One controller is apparently sealed.

The link suggests that stopping is based on the motor current drawn.

Could you improve on the design. Probably.

If you could post a pic of the internals, it could be a plus.

 

[downtowndarrel]

I need a control module attatched to a 12vdc motor, to control: direction of motor, with limit on both directions, without the use of limit switches. The only thing I can think of using is a load limit switch, almost like a circuit breaker that doesn't reset until the motor changes direction. Anybody follow me here??

 

[downtowndarrel]

I need a control module attatched to a 12vdc motor, to control: direction of motor, with limit on both directions, without the use of limit switches. The only thing I can think of using is a load limit switch, almost like a circuit breaker that doesn't reset until the motor changes direction. Anybody follow me here??

I dont have a pic of the internals, seems to be hidden, (in epoxy).

 

[KeepItSimpleStupid]

Ah, yours is the epoxied one. The one that they say a resistor dies.

I would probably start with a DC bipolar current sensor such as one of these: https://www.pololu.com/category/118/current-sensors

The initial current spike has to be ignored. You would probably have to filter the brush noise too.

In general, the direction relay and a NOT ENABLE relay is usually the way to go. Sequencing can be done better that way. e.g. the direction set and then the power turned on.

So, I could see optocouplers looking at the fwd/rev switch and the ignition switch signals.

If you wanted to save the state, you could use an I2C FRAM memory or a magnetic latching relay.

 

[downtowndarrel]

Ok, I found this discription:
The control unit is essentially a current sensor as well as a switching device. When the motor assembly moves the step tread to its extended position, or stops moving because of an obstruction, such as a curb, or binding of a damaged or bent step frame, the motor draws a larger amount of current. The control unit "senses' the larger current draw and shuts off power to the motor.

I'm still looking for a diagram for this module.

 

[KeepItSimpleStupid]

Basically, yes. I saw that.

And that is why, I would make a bidirectional hall effect current sensor the heart of a new system.

Brushes create noise and when the system starts up, there is a large current draw. These have to be ignored.
So, a simple, Current exceeds X amps for Y time may work. For greater sensitivity, you might add. ignore I(t) for Z mS when motor is started from rest. I(t) is current as a function of time.

Some time in the 80's I was working on a gantry crane for a model railroad and I needed some method to prevent damage to the motor/components if the gantry were to hit a hard limit. I selected components such that a cap charged when the current was exceeded and then it turned on an SCR which dropped the regulated voltage to zero. Reset required the power to be recycled.

The direction tells you if it's a forward or retract limit.

So, your code may say, if I'm at a retract limit, I can only extend and if I'm at a forward limit, I can only retract or you can ignore it and the motor would try to move a small amount and stop.

The other logic is safety, like don;t move the steps if the trailer is moving (Ignition on).

And for convenience, extend the step when the door is opened (only once) after the Ignition key is turned off.

And the other is retract the steps if someone forgets to. Use the On when engine running type of signal like the ECM power.

And deal with manual accordingly. You could allow jog FWD and jog REV.

 

[downtowndarrel]

Well, I ordered and got one of these control modules. I carefully took it apart. It was filled with a silicon type of epoxy, flexible not hard. Upon disassemble I immediately realised that I would not be able to reproduce this unit because of the complexity and the fact that it's all micro circuitry. I did find this on the circuit board: IDS, Inc. 11077-D.
Here's some pics:

 

[downtowndarrel]

Can some one help me build a circuit similar to the above, but using micro switches for the out and in limit, and relays for the switching? It would be best if it were a simple circuit.

 

[downtowndarrel]

Can some one help me build a circuit similar to the above, but using micro switches for the out and in limit, and relays for the switching? It would be best if it were a simple circuit.

I will not be using this circuit for steps of any kind. Also found out that the company that makes this is partners with microsoft.

I need this simple circuit to control a 12vdc motor that runs a cable attached to a slider in a track.

#1 When power is supplied to the circuit, the motor moves the slider to it's end point, then stops.

#2 When power is removed from the circuit, the motor runs in the opposite direction, moving the slider in the opposite direction as well, until it reaches it's end point, then stops.

(This can also use the ground as the control for the circuit, i.e supplying ground and removing ground)

I know this can be achieved by using relays and micro switches. Just needing a little guidance here please.

 

[4pyros]

#2 When power is removed from the circuit, the motor runs in the opposite direction, moving the slider in the opposite direction as well, until it reaches it's end point, then stops.

How can the motor run with no power?

 

[KeepItSimpleStupid]

The circuit gets more complex if the current is high. What is the current draw of your 12 V motor?

In the simplest implementation.
1. One can use a DPDT or DPDT center off switch that reverses the polarity of the supplied power.
2. Two limit switches are such that the normally closed position is opened at the limit.

At this point, you have something that will stop at either limit, but would not be able to go "the other way".
So, you place a diode across each of the opened contacts that allows the current o flow in the opposite direction. (A diode at each limit switch).

 

[downtowndarrel]

How can the motor run with no power?

There is a constant power and ground supply to the circuit, but the way the circuit works, it stops the supply to the motor when it reaches it's limit.

 

[downtowndarrel]

Here's another description:

When the switch is turned on, it applies power to the motor, and to movement.

When the movement reaches the end of travel, the module senses increased current demand because the motors are pushing against the 'stops'.

At this point, the module removes power from the motor to keep it from overloading.

When the switch is turned off, the polarity of the motors is reversed and applied, and the movement is retracted.

Again, at the end of travel, power is removed when resistance to the motors is sensed.

(This is from a retractable headlight control module.)

 

[downtowndarrel]

Here's more:

The 1987-1988 Fieros use a new headlight system, which is also used in 1987 and later Firebirds. This system has two motors and an electronic module which controls their operation. Here's how it works:


There are only two wires connected on each motor. (one motor per headlight) Green(/black) and grey(black), and they connect to the output (4-pin connector) on the headlight control module. The other connector (5-pin) on the module is the inputs. The two red wires are the continuous power from the battery through two fusible links, as in the 84-86 system. The white and yellow wires from the headlight switch are also the same, as is the ground.


Everything on this system is done inside that little electronic control module. When the headlight switch is on, it trys to run the headlight motors in the up direction. When it is off, it tries to run them in the down position. Rather than having seperate wires for each (and ground), as the previous system did, this one reverses the flow of current across the wires to turn the motor in the opposite direction. Also, rather than having an internal limit switch inside the motor, the control module actually senses the current being used by the headlights. When there is a sudden rise in current draw, as happens when the motors can no longer turn, the module shuts off the power to the motors.

 

[rumpfy]

For what it is worth;
Have you considered the operation of the extending aerial used in motor cars. This seems to be functionally, what you want.

 

[downtowndarrel]

For what it is worth;
Have you considered the operation of the extending aerial used in motor cars. This seems to be functionally, what you want.

Yes I have. I actually have one that I experimented with. These are built with a clutch, so that if you stop the antenna from extending, the clutch slips, but the motor still runs until it reaches the limit. Motor limit is controlled by a rotating contact disc that disconnects the motor when it reaches a certain position. Almost a "time limit".

 

[4pyros]

How much travel do you need.

 

[downtowndarrel]

How much travel do you need.

I will be using a power window motor and track, so yea, about that much.

 

[KeepItSimpleStupid]

Do you have an idea about how much current the motor draws?

Can the system consume a little power when at the limits? Like the current to a relay coil?

Would a DPDT switch work for you?

Center off just would allow you to stop it part way, so it's not necessary.

Are you OK with a fuse if the limit switch fails?

Do you have enough expertise to make a stop on over current circuit with guidance? I wish I had time to learn simulation.

Look at the chicken coop door threads here.