Learning by Doing

[pstephens]

Browsing the AD catalog, it looks like their GS1 series AC drive would be adequate. They will work with 1/4-1/2 hp on single-phase input. The GS2 adds dynamic breaking (plus other features that don't seem needed here), while the GS1 uses DC breaking. I'm not sure exactly what this means, but it doesn't seem to me like braking is a big issue with this application, since the inertia of the roll won't be transmitted to the wire during deceleration (hence the possible need for a separate brake for the roll).

I say five inputs to the drive like this:

2 for direction, forward and reverse. (Just in case of overshoot)
1 input for high speed to take off and accelerate.
1 input for slowdown to creaping speed.
1 input to plug the motor, or in the case of a dc motor to fully energize the field. to hold the wire in place for cutting.

Hence 5 inputs.

Question from a PLC dummy: I assume these inputs to the drive would be outputs from the PLC?

 

[elevmike]

YES... The inputs to the drive would be driven by outputs on the PLC.

 

[elevmike]

Browsing the AD catalog, it looks like their GS1 series AC drive would be adequate. They will work with 1/4-1/2 hp on single-phase input. The GS2 adds dynamic breaking (plus other features that don't seem needed here), while the GS1 uses DC breaking. I'm not sure exactly what this means, but it doesn't seem to me like braking is a big issue with this application, since the inertia of the roll won't be transmitted to the wire during deceleration (hence the possible need for a separate brake for the roll).

Dont worry about getting too many features.. They wont get in the way.

DC braking is basicly replacing the sine wave with a flat DC signal. This will magnetically lock the roter in place, and possably negate the need for a mechanical clamp to hold the wire for cutting.

Additionally if you think intertia might not be a problem with the roll, for get the mechanical brake for now. If it turns out to be a problem you can add it latter with very little effort.

 

[Doug-P]

Bells & Whistles

Couple of more thoughts...

4) You may also want to add another button to initiate the encoder count. Like when you first install the wire, you would manually jog the leading end to the shear then press the reset button to zero out the encoder.

If the wire could be man-fed to the pulling mechanism and from there reliably threaded to the shear without further manipulation, LS#2 from post #15 could be used to sense the wire, cutoff the short initial piece, and reset the encoder. One could even make it such that the machine would just go on from there or wait for one more "OK to go?" input.

.02

 

[pstephens]

Originally posted by elevmike1) You may not need the clamp if you're able to achieve good traction; the drive unit and motor could hold the wire in place for cutting.

This would be a definite advantage. It won't take a lot of holding force anyway, given the rather generous length tolerance. And I don't believe the shear exerts any appreciable axial force on the wire during cut-off.

3) You may want to add two more buttons to your panel, Jog Forward, and Jog Reverse. They would be used to assist in feeding the wire through the drive unit.

Great idea! I know my customer would be interested in this feature.

Your program could also keep track of the total amount of wire used by accumulating the lenghts of each cut. This value would be stored in retentive memory. This way you can display the amount used, or left on the reel over time. So lets say there's only 10 ft left on the reel and the cuts are 11 ft long. the unit would automaticly stop before pulling the end off the reel. This value could be accumulated for days or weeks until the reel is used up. You can also display if you have enough on the reel to complete the current job. On and On and On etc...

More great ideas -- how difficult is it to program these various features? Are these all compatible with the DL06 and the EZT panel?

 

[ArikBY]

OK

Here is my opinion at 5.30 AM.(what is worth)
First this kind of systems dont work in 2 direction.
Unless you going to have feed motor.
So from the PLC side you need:
Start input
Stop input
Encoder A input X0
Encoder B input X1
VDF is ready input
Master relay On input(E-Stop OK)
(Jog will be program on the EZ fun key)
To be on the safe side you can add sensor to make sure the roll ended/
wire missing ect..
From the output side
Run VFD output
Speed change output
Clamp output (I dont think it necessary too)
Maybe bazzer or flash light.

By the EZ you will input
Length
Deceleration length (it cahnge according to the pulling speed)
Size of the batch you want.
and some other counters if you want.

Very simeple

You can also add potentiometer for speed control or you can use 2 fun key for Up&Down the speed.potentiometer would be easy.

In one of the other threads someone complain about the quality of AD VFDs,I dont have any experience with then,from the other hand I have hundreds of installation of Omron and Yaskawa J7 without any problems.
Some of them in similar application.


I hope I covered all.

 

[Eric Nelson]

I'll add that you might be happier with a separate 'JOG' pushbutton button connected to a PLC input. If you use an EZ-text key to jog, it won't be as responsive due to communication delays between the EZ-text and PLC.

Press 'JOG' key...slight delay...Motor starts.
Release 'JOG' key... slight delay... Motor stops.

This can be annoying...

beerchug

-Eric

 

[ArikBY]

Thanks Eric

The jog work with timer.momentary push low speed.long push high speed
So the communication delay is not so bad.
Anyhow there is enough spar inputs.

Eric I think you mention something about AD VFDs in the past?

 

[Eric Nelson]

Eric I think you mention something about AD VFDs in the past?

Yes Arik, I've not had good luck with the GS1s, though I wouldn't NOT recommend them. <-- double negative = positive

I stated the problem in THIS THREAD at the A-D forum (I'm ericn there), which also points back to a post here at Phil's.

beerchug

-Eric

 

[elevmike]

I still go for fowrawrd and reverse. This would enable you to jog the end cut back out of the traction drive unit with out having to grip the wire with a plyers or someting. I understand the chance of overshoot is very small, but I just think that for the trouble, all it would take is programming, why not add it? So I vote for pb jogging in both directions..


pstevens,

The programming necessary to track the amount of wire used on the reel would be real simple. If your new to this, count on a few extra hours in DirectSoft to add this feature. No more parts required though. This can be added latter on at anytime.

I saw in the AD catalog the GS1 has a model that will operate from 115vac 1 phase. Please dont get too excited about that model. I would reccomend that the main power supply for the drive be at least 220 1 phase. 3 phase is better.

 

[elevmike]

Ok another proposed drive input setup (4 inputs on the GS1)

1) High speed forward.
2) low speed/jog forward
3) low speed/jog reverse
4) Brake/stop hold

 

[pstephens]

Hi All,

I'm a little late checking in here -- the stuff from AD arrived around 8:30 today and I've been like a kid on Chistmas morning!

While looking over the DL06, a question occurred to me. When I ordered it with the DC outputs, I was fairly certain that I would be interfacing with a stepper system. If I switch to using an AC drive, are the DC outputs still compatible?

Responding to some of the posts since last night:

Originally posted by ArikBY
...this kind of systems don't work in 2 directions.
Unless you're going to have a feed motor.

I was a bit taken aback by this at first -- you mean that you can't reverse an AC motor with an inverter?? Then I realized you probably meant that it's not practical to reverse the wire travel (at least not very far) because it won't go back on the roll (without some kind of positive drive on the roll). Of course, the small reverse movements necessary to correct an "overshoot" on the encoder would not be a problem.

By the EZ you will input:
Length
Deceleration length (it change according to the pulling speed)
Size of the batch you want.
and some other counters if you want.

Arik, I'm not quite sure what you're saying here. This would be something the machine user would input?

Originally posted by Eric Nelson
...you might be happier with a separate 'JOG' pushbutton button connected to a PLC input. If you use an EZ-text key to jog, it won't be as responsive due to communication delays between the EZ-text and PLC.

Yes, this is a good point. Also the membrane PB's on the EZtext don't have the right "feel" for a jog button. I prefer a standard 30mm oil-tite PB for this function.

Thanks for the advice, Arik and Eric, about the issues with the GS1. Since I have no experience with any of them, I will take your recommendations to heart.

Originally posted by elevmike
I still go for forward and reverse. This would enable you to jog the end cut back out of the traction drive unit with out having to grip the wire with a plyers or someting. I understand the chance of overshoot is very small, but I just think that for the trouble, all it would take is programming, why not add it?

I tend to agree, at this point. But it's not something that has to be decided once and for all right now. I'm still leaning toward having an air cylinder and solenoid valve control the tension rollers on the traction drive. Maybe a safety issue -- when the E-stop is pushed, the valve output is killed, and the drive pressure releases.

I saw in the AD catalog the GS1 has a model that will operate from 115vac 1 phase. Please dont get too excited about that model. I would reccomend that the main power supply for the drive be at least 220 1 phase. 3 phase is better.

The only reason I'm leaning toward the single-phase is that my customer wants this machine portable, but I think he just means that he doesn't want a hard-wired conduit drop. He would like to be able to move it around just in the area where it's normally used. I am going to see him tomorrow, and I will ask him about this. I'm fairly certain we could use three-phase, if that makes for a better running machine.

BTW, I got a call from my customer this morning telling me that the 500 lb. roll of wire arrived. "Yikes!" Now he's wondering if this is going to work. He said that the wire was not rolled very uniformly, and the design for the unreeling unit may have to compensate. He seemed a bit apprehensive. (As a point of reference, has anyone here worked on one of those lawnmower recoil-starter springs? Picture one of those that weighs 500 pounds!) Here we go...

 

[elevmike]

While looking over the DL06, a question occurred to me. When I ordered it with the DC outputs, I was fairly certain that I would be interfacing with a stepper system. If I switch to using an AC drive, are the DC outputs still compatible?

Yes... Your are ok with the DD1 either way. However if you have to turn on a 110vac inductive load, like maybe the valve solinoid, you will have to use an isolation relay. 15 bucks maybe..

I was a bit taken aback by this at first -- you mean that you can't reverse an AC motor with an inverter?? Then I realized you probably meant that it's not practical to reverse the wire travel (at least not very far) because it won't go back on the roll (without some kind of positive drive on the roll). Of course, the small reverse movements necessary to correct an "overshoot" on the encoder would not be a problem.

The inverter or dc drive motor setup will reverse. Arik, is just stating that for the most part you will not be going in reverse, the intention is to go forward. My thought on this is that you may need to reverse from time to time to unload the machine, or enable it to make corrections in the case of roll back. Presumably the lead off wire from the reel to the driver will absorb the small amout of reversal movement of the wire.

Arik, I'm not quite sure what you're saying here. This would be something the machine user would input?

The user could set the length, and set the speeds etc, and/or you could predetermine all that in the programming depending on the length of the cut. It's all in the programing so right now it's putting the cart in front of the horse. You'll know more after testing the unit as to how you'll handle this. Make the machine..

Thanks for the advice, Arik and Eric, about the issues with the GS1. Since I have no experience with any of them, I will take your recommendations to heart.

If Arik says no GS1 you may want to take his advise. From the catalog discription it looks like a good bet, but bad/good expierance by others is an important consideration.

I tend to agree, at this point. But it's not something that has to be decided once and for all right now. I'm still leaning toward having an air cylinder and solenoid valve control the tension rollers on the traction drive. Maybe a safety issue -- when the E-stop is pushed, the valve output is killed, and the drive pressure releases.

IMHO this sounds complicated, I would think a tension spring could apply 50lb or so of force to apply the tension/idler rollers aganst the bottom of the wire to force it into the traction drive roller.

The only reason I'm leaning toward the single-phase is that my customer wants this machine portable, but I think he just means that he doesn't want a hard-wired conduit drop. He would like to be able to move it around just in the area where it's normally used. I am going to see him tomorrow, and I will ask him about this. I'm fairly certain we could use three-phase, if that makes for a better running machine.

All of our machines are plugged into twist sockets for either 220 vac 1 phase or 220vac 3 phase, with a cord. This allows us to move stuff around the shop in case we need to.

Also regarding power supply; you will need to add a manual reset drop out protector. This is basicly a contactor with a self holding circuit through an aux contact on the contactor. If the power drops, or cycles due to power inturption, it will prevent the unit from turning on and off etc.. This is an OSHA requirement.

 

[ArikBY]

Hi

I am sorry.I am not in my best at 5.30 AM
When I saw what I wrote I know what I mean,But I did not wrote it right.
What I mean is when you come to the cutting point you need to change the wire speed to get the exact length.that point is depend on the speed so it someting the operator can change.
For example if the desire length is 12' the deceleration point would be 1'less.so in 11' the speed will change. let say from 50Hz to 5 Hz to reach the cutting point.

That point is tracking the length so for different length it still good.for different speed it might be not.
I hope Iam clear now.

 

[elevmike]

To furhter simplify the slowdown issue...

I really think that in the end, unless the cycles are VERY fast, you will probably end up using one slowdown distance for all length cuts. However if this dosnt pan out during testing, (if you discover you have overshoot on short cuts), you could add code to adjust slowdown distance revelevent to the length of the cut.

Example:

12' cut = 12" slowdown
10' cut = 10" slowdown
9' cut = 9" slowdown

Etc....

My guess is that your going to reach terminal speed on all cuts, therefore you will use the same slowdown distance.