Need Wiring Help For 12 Volt Motor

[vtsteam]

Ugh.... just remembering that one of these joysticks is "momentary" (from first post) -- does that mean it's self centering? Probably.

In fact I'll bet they're both self centering  --- yes? Typical 4 way switch joysticks, right?

Okay ditch the reversing joystick and the reversing relay and just buy a simple DPDT switch for direction. There's no point in a 4-way self centering joystick and relay for this!

And for the other, just rig up a momentary push button for fast traverse! You can do it with velocette's pot shorting method.

Add a RUN/STOP switch and you're done.

Then things truly are simple!

[snub]

Thanks for all your effort, vtsteam. It is much appreciated. When I was a youth I could comprehend all of this but my 60 year old brain is not what it used to be. Those joysticks are a joy to use and that's why I wanted them. I was searching Ebay today and think I may have found some DPDT joysticks. Plan C is I will simply use some DPDT switches and add some long handles.  I just hate buying new stuff when I already have a bunch of parts that need to be used somewhere.

Again, thanks to all for your help.

[vtsteam]

No problem Snub, puzzles are fun, but sometimes you reach a dead end -- or at least I did.

The real problem was that spring loaded centering joysticks had no way to maintain a direction.

If center was forward, how would you put it in reverse without holding the joystick over? You need a detent at both ends of the throw, and no middle position -- like how a normal 2 position toggle switch works.

Fast traverse/slow cut would work okay with one of your joysticks, if you made the center position the slow cut speed, and one end or the other the fast traverse. Since that only needs to be momentary

But since you really have a 4 position stick you would have to waste 3 of those outer positions -- as either redundant, or having no effect. It's certainly do-able, but not what I think you wanted.

Ideally you would have a 3 position stick, not spring centered, that gave fast, off, and slow as the three positions. But it would have to stay in each of those positions, except fast, which could be momentary.

So the real difficulty was that the sticks were self centering. We can't make up for that with circuit changes. It's a mechanical problem.

[DMIOM]

These joysticks seem to be causing some confusion ( my fault ). They are 4 way joysticks with 4 separate SPST switches. They go left, right, up and down with center off. I am only using the left and right. All are normally open contacts......

IF the movement is constrained so only one switch can be operated at a time (i.e. only N, S, E, or W) by an irremovable " + " shaped gate then ignore this.

However, IF the movement is unconstrained and you can move it to any direction in a circle (in particular NE, SE, SW, NW) then here's a suggestion for the 'user interface' using just the one joystick:

UP (high) and right - High speed to the right
DOWN (low) and right - Low speed to the right
....and similar to the left

Dave

[vtsteam]

Yes Dave, but with self centering joysticks you'd have to hang on to them throughout the cut. (also, I think this is only a single axis drive. The functions needed are ON/OFF, FWD/REV. and MILL/TRAVERSE.)

The only true "joystick" operation should be fast traverse. Let go of a stick and it stops. Everything else should be able to hold in position. It's a mechanical problem, not a wiring problem.

Imagine if a car transmission stick returned to neutral as soon as you let go of it.

The controls need to stay in position.  That's the function of a bat switch, not a joystick.

The other function of either of these is to indicate intuitively what is going on. A forward handle should indicate forward travel, for instance. Or high speed, etc.  Thus "blip and latch" electronic controls (like the volume button for a TV remote control) have poor user feedback when used for a machine drive. Handle position is extremely useful as an indicator, as well as a means for changing an operation.

[bertie_bassett]

i think im really confused about those joysticks now.

so they both have 4 N/O contacts one for each direction, up down left and right?

one of the joysticks is momentary and returns to the center

and the other one? my understanding was it wasnt momentary, so therfore must latch in whatever position its moved to e.g left

do you have any info from the supplier? i think they may be modable to 2P3T

[snub]

The joysticks only move in a "+" shaped gate. 4 separate SPST switches with center off. Much like the controller for an old video game  like Pacman. You can move your "man" up, down left or right. But you can't move up and right (for example) at the same time.

I chose the "latching" one for slow speed milling (in both directions) so I could stand back and watch the machine work without having to hold the switch on. I chose the momentary switch for fast travel in both directions since the table moves quite quickly.

I chose the 4 way sticks for 2 reasons. First, I may add a motor to the "Y" axis so I could use the same sticks to control that. Second, they were dirt cheap. $16.00 for the pair delivered from China. They were manufactured by Schneider Electric, but are obsolete, so not much info available.

[velocette]

Hi
I fully understand this ""Plan C is I will simply use some DPDT switches and add some long handles.
 I just hate buying new stuff when I already have a bunch of parts that need to be used somewhere"".
They are certainly a pleasure to use hence the name "Joystick".
Have Added A sketch of the system I use on a similar controller plus photos of latch to prevent "Instant Reverse"

Eric

[vtsteam]

So, snub, one of your sticks latches at either end of the travel? It will stay in the position you put it in? Because if that's true, then it is possible to work it out.

[snub]

Yes, the joystick for the slow speed machining maintains its position until you manually return it to neutral, just like a normal switch. Thanks for your help vtsteam, but I think for now I am just going to throw some DPDT switches in there and be done with it. If I decide to add a motor to the Y axis, I may then persue this.

I did a project similar to this years ago and now I recall that I had problems with the relay coils not de-energising fast enough when I was reversing the motor direction. If I flipped the switch too fast, I would blow the fuse. I believe it was the fault of the PWM.  It had an LED light on it to show it had power but when you turned it off the light would still glow for several seconds, then slowly dim to nothing.

[vtsteam]

Darn, Snub, I finally had an idea that I think would work very easily and straightforward. I could draw it up quickly with those sticks.

Instead of one stick for direction, and one stick for speed, we could make one stick for high speed, and one for low. Direction could be set by either stick -- forward for forward, back for reverse. Both sticks in neutral would be motor off. This would require only your two relays. The slow stick would detent in either forward or reverse.

If you wanted to add another axis, all functions would be the same for that axis as well, so it would work perfectly for a 4 direction joystick. One stick would be fast traverse for both axes, and the other would be slow for cutting for both axes.  Very simple to set up and the circuit diagram would be symmetrical.

Your problem in the past was due to the motors acting as generators before they stopped when you reversed direction -- that increased the current momentarily, blowing the fuse. You might get by with a slo-blo type fuse if the current spike isn't too great. Also with a center off position, you might get a little more time for a slowdown before reversing.

The reason the LED glowed after it was turned off was unrelated -- there was just probably a capacitor in the circuit wth the LED, and it needed to discharge completely before the LED stopped glowing.

[snub]

Instead of one stick for direction, and one stick for speed, we could make one stick for high speed, and one for low. Direction could be set by either stick -- forward for forward, back for reverse. Both sticks in neutral would be motor off. This would require only your two relays. The slow stick would detent in either forward or reverse.

That is exactly how I had envisioned it working. I know now that I hadn't explained it properly in my first post. Either that or we need a USA/ Canada translator. Living in Vermont you are not far from Canada but I know your immediate neighbours to the north don't speak the same language.

The problem I am having is converting your schematics in to actual wiring hookups. All is good except for the relays. My scanner is still on the fritz so I can't show you what I came up with, but here is a picture of how I drew up the wiring diagram when I motorized my lathe. Works perfect.


.
'

[bertie_bassett]

well iv had another quick go at a possible solution and have come up with the following:




the latching joystick sets thing in motion at slow speed, and the momentary will bypass the pwm for full speed.

if the momentary joystick is used on its own, nothing will happen.

not quite what you were after but it might do you?

two things to note though, iv common'd up the pwm -ve with the  supply -ve, and in fast mode 12v is supplied to the motor and the + output of the pwm modual. i dont think either of these will be a problem, but without the part in my hand i cant be sure

[vtsteam]

Bertie, hard to read as drawn, but looks like in the state you show your circuit you have PWM + going to both sides of the motor. Haven't checked anything else.....

snub, sorry about my own mistakes in reading your first post.  I'll try my hand at a drawing one more time and post something (I hope) tonight. I'll try to make it more like your drawing and less like a schematic, if I can.

[vtsteam]

snub, okay I worked out a circuit. It is for only one of the joysticks, and one of the relays  just to make it easier to understand.
The other one would be identical except it would also include the PWM in the circuit. The one I'm showing here would be the fast speed Joystick and relay. I'm going to show it first as a schematic, and later try to do a block wiring diagram like you showed.

But I'm hoping that you will be able to "get" what's happening here first, since if you have the concept, it will be easy for you to draw out your own diagram.

First, here is the schematic (I'll explain it next post):

[vtsteam]

Okay, the explanation:

Your relay should have 8 connection locations on it.

2 for the coil (from your picture, first post, it looks like they are the bottom 2 larger lugs)

6 for the DPDT switch that the coil operates.

That DPDT switch is just like any other normal DPDT switch. It seems like you know how to wire a DPDT switch -- this is no different.

As you probably know, a DPDT switch is basically two switches in the same case that are mechanically connected together, so they close at the same time. And those two switches have a center movable contact that closes with fixed contacts at ether end of the switch. So you have two connected positions for the switch.

Using the DPDT switch analogy, a relay has a spring in it holding the switch closed to one side. When power is applied to the relay's coil it moves the switch to the other side. That is the whole operation of a relay.

The center contacts on the relay's switch are called the "armature", and the switch's end contact is either referred to as "Normally Open" or "Normally Closed", depending on which end it is located at.

When no current is flowing through the coil, our switch is held by the spring to one side, and the contact on that side is the "Normally Closed" contact. The contact on the other side is not connected to anything, and so is the "Normally Open" contact. That's all there is to that.

Your relay should have the connection lugs labeled, and/or a small schematic diagram indicating which contacts are which. If you can include a picture of that it will be easier to draw you a wiring diagram, like the one you showed.

Okay, so that's relays. Next, the joystick.....

[vtsteam]

The joystick you have is a 4 way joystick with 4 SPST switches, one for each direction, and a center position where no switch is closed.

I don't know whether all 4 switches are connected together on one contact of each switch (in other words they have a common connection) or whether they are completely independent,

We want two of the switches opposite each other to be connected together on one of their contacts. So if the joystick is already common connected, fine. If not, you can do that manually with a short wire.

That common point will also be connected to the + side of your power supply.

Therefore, when you move the stick to either extreme, one or the other switched contacts will get + voltage on it.

So much for the joystick. Next......

[vtsteam]

Now our relay coil can only be ON or OFF, but we have a joystick with 3 positions on it -- Left, center, and right.

This means two positions of the joystick (center and one side) will have to do the same thing, as far as the relay goes.

I'm choosing to de-energize the relay for 2 positions of the joystick, and energize it for one. So how do we get 3 different results with the mill table out of that?

To solve this problem we are going to let one joystick switch make a dual connection, and the other switch make a single connection, while the center position will make no connection -- three different circuit results, which can yield three different movement options for the mill table.

The first switch will pull in the relay, AND supply current to one relay contact. In this case a Normally Open (NO) one. Since the relay will be energized, this contact will be closed, and if it is connected to the motor, it will run.

The second switch will NOT be connected to the relay coil, so cannot pull in the relay. Instead it will be connected to a Normally Closed (NC) contact and since the relay isn't energized, that contact will be closed, and will be able to pass current to the motor. In this case it will be connected to the opposite contact on the motor than the first switch was, and so it will run the motor backwards.

The middle joystick position, will not connect the + side of the power line to anything. Not the relay coil, or any contacts. Therefore, the motor cannot run.

The rest of the circuit is there to connect the minus power supply to the relay contacts, in such a way that it gets connected to the correct side of the motor to complete the circuit, depending on which joystick switch is active.

[vtsteam]

Here is a picture of the first schematic (without labels to make it easier to see) and the same circuit with the PWM added -- this would be the second joystick, the one with the detents.

Obviously they would share a power supply when you build it, but I've kept that apart to make it easier to read here. You would probably also add a fuse, pilot light, and on/off switch for the power supply -- but again, I left them out for clarity sake.

(ignore the pin numbers on the PWM in the drawing -- they were auto-numbered and may not match your PWM speed controller)

[snub]

vtsteam, I really appreciate all this but I'm still slightly stumped. On your schematic/diagram (post #39) it appears to me that the relay has 10 connections. My relays function exactly as you described in post #40. I have to go as there is smoke pouring out of my ears from overloaded brain.

[vtsteam]

Snub, sorry -- I think I see your problem -- the circles (hollow dots) are contacts inside the relay. Black dots are the lugs outside of the relay where you make your connections to it. The arrow represents the movable part of the switch.

So there are:

2 lugs on the relay for the coil

and 6 lugs on the relay -- for the two switches.

each switch has a center movable part, and two contacts, one normally closed, and one normally open.

[vtsteam]

Here's a picture  of a relay:



It's a DPDT relay without a case. You can see the two different switches. I've labeled the parts. The upper contacts are the NC ones because the spring is holding the ramature's contacts up against them. The lower contacts are the NO contacts because the armature contact is not touching them.

If the coil is energized, the armature pulls down and breaks the connection with the upper pair of contacts, and makes a connection with the lower pair.

[vtsteam]

Relay contacts without and with coil energized. The middle contact is the armature:




Schematic version:

[vtsteam]

Here's a simple relay (SPDT), and a DPDT relay.


Notice there are 8 connections to a DPDT relay.

2 to the coil

NC, NO, and armature to one switch

and

NC, NO, and armature to the second switch.

[snub]

Believe it or not, I am grasping everything..........except the connections to the relays. Once we get through this we will be good to go and you can get back to your own projects. Unless you are up to your waist in snow. Here is a picture of the relays I am using and their terminal connections. Got to love those clear plastic cases, you can see the guts inside. No guessing as to the proper hookup.

Update:
Don't bother clicking on the picture. The diagram is wrong.