GML UltraMaster question

Hey guys. I have a drive that I need to be reversible with the touch of a Panelview. This is again uncharted territory for myself. The drive is an AB ultra drive, and the parameters that I have found are Ultramaster software. The drive is currently set up to run using the follower: master encoder function. My question is, is there a way to reverse this master encoder function with a bit in the PLC and send it to the drive telling the drive to run the exact speed and distance it would normally, except in the opposite direction. I am having trouble finding exactly what the master encoder is and where the drive is getting the information for it from. Any help is appreciated.

Russ

Hi,

I think I can help, but a little more information is needed:

Which Ultra drive model is it?

Ultra 100/200 or DeviceNet/Indexing version, Ultra Plus, Ultra 3000, or Ultra 5000?

Which motion controller are you using?

And what is the PLC interface that you are using please.


If I understand the question rightly, are you asking if it possible to reverse the sense of the gearing between the master axis encoder and the slave motor axis?

more info

The drive model is a 1398-ddm-009. It is talking to a PLC5000. I have found the command in the PLC that enables the follower input in the drive, but I have yet to find or understand how the drive knows what it is following.

The easiest way for me to accomplish what I want would be to have a panelview bit reverse the direction of the conveyor in question, while still keeping it geared to it's master encoder. I am wondering if this is possible, and I am also wondering how/where I find that master encoder so that I know exactly what it is the drive is following. Hope this info helps.

Russ

Russ,

It is easier to help if you can post ALL the details asked for.

The term PLC5000 is less than exact. Do you mean a ControlLogix 1756 system?

And I am left to guess that the motion controller you are using is a 1756-M02E modules??

Sorry

Philip,

I must apologize for being so vague. I was pressed for time at the moment of my reply. I have found a manual for the drives, and I now understand a lot more about the process. For clarification, yes, PLC5000 was meant to be Control Logix5000. Yes, we are using the mo2ae cards.

The drive in question is run under normal circumstances as a follower. There is a master encoder mounted on one of the motors used on the line, and the conveyor I am concerned with follows this encoder. When the line runs, "my" conveyor runs the same direction, at the same speed. Because of some new products being brought in, operators need to be able to make "my" conveyor run in the opposite direction, with all other variables being the same, same speed, same time, etc. My question is this, and I am doubtful of getting a positive answer: Is it possible thru ultra drive parameters to reverse the rotation of "my" conveyor, while still using the follower setup in the drive.

It is my thinking that I will not be able to do this with an input bit from the PLC to toggle the direction. If I cannot do this, I am wondering what the simplest, most logical method is to make my conveyor run the same distance in reverse that it would were it running forward.

Russ, thanks....I wasn't sure of how to answer until I understood what part of the system is doing the motion planning.

You have three main subelements to you system.

1. The 1398 is a servo drive that accepts a +/- 10v analog VELOCITY command signal, generates a torque command to the motor and closes a velocity feedback loop from the motor encoder back to the drive.

As an anciliary function it also re-transmits the motor encoder signals and sends them to the M02E module that will use them as POSITION feedback.

2. The M02E module accepts "coarse" motion planning move commands from the 1756-Lxxx CLX processor accross the backplane. The M02E then closes the position feedback loop. It does this by running a "fine" motion planner in the module at I think 100usec intervals and send the 1398 the analog velocity command.

3. The CLX processor is generating the POSITION commands and runs a "coarse" motion planning task every few mSec. It then sends these commands accross the backplane to the Mo2E modules.

OK...all up where is the logical place to define the motion??...answer, in the CLX motion instructions which are generating the moves in the first instance.

I can see where the question is coming from because the 1398 has so many programable functions it is tempting to try and achieve lots of functions with it. I know ...I once did a whole toothpaste tube capping machine with one.

A big problem that would arise with changing the encoder direction sense in the 1398 drive (even if were possible to do so) is that the M02E position controller would ALSO need to have it's feedback direction sense changed at the same instant...otherwise the position loop would have positive feedback, and instantly run to a limit.

But in this case you have the resource of the CLX system to do all the motion planning and logic...and this is the best place to define all the moves you need to run your conveyors.

Good luck

Someplace in the logix code is probably a number that is the "ratio" value of the following function. It tells the drive at what ratio to follow the master encoder. In order to reverse the drive, simply negate this ratio value.

Be careful, though. it will reverse the direction right now. So make sure the drive is at zero speed before reversing it.

If the control mechanism is gearing, then reversal is simple. Find the relevant MAG instruction, edit it to use a tag for the direction parameter, then add logic to manipulate the tag and toggle the MAG whenever the direction change is required. Enter an appropriate "clutch rate" in the MAG instruction and you won't have to stop first.

If, however, the control mechanism is camming (MAPC instruction), you'll need to expend a little more effort - i.e. set up a pending cam.

Solution

Sorry for not answering sooner guys. I have been busy. Earlier this week I did some real digging. I expected the system to be much the way you described. What I actually found out though was that this system is a little different. All the M02AE cards are used on other axis on the system. The 5000 rack is actually full, so, instead of adding an expansion rack, another MO2AE, along with the other cards necessary to put this last axis on the 5000, it's follower is instead an actual master encoder that is mounted on one of the existing conveyors. This control logix was put in during a "remodel," and i guess the engineers did not deem the project worthy of the extra 7-10 thousand it was going to take to convert the drive over to the new system. So, they opted to use all the existing hardware for just that one drive. So, literally, the drive follows a master encoder which is mounted to the line. The drive enable, and follower enable both come from the PLC. That is all. To reverse the drive, I have been advised to use a reed relay, which I am not familiar with, to reverse the signal wires on the "master encoder" that is wired to the drive. Hopefully just using a PLC output to toggle this relay will reverse the drive. It's kind of a band aid way to do what we need to do, but it is a cheap solution. Thanks to all for the help.

Russ

Russ,

There's something you need to check before you do the relay thing.

Is the master encoder quadrature? That is, does it have channels A and B? If not, it is not direction sensitive. To reverse the direction, the A and B channels must be switched--both ends, + and -, of both channels--this means 4 spdt contacts--gold reed contacts.

[The ultra won't let you reverse via outside input in follower mode, but it will in velocity mode. You could get one of those frequency/voltage convertors from dynapar or one of the other encoder mfrs. These things take a pulse train input and output a prosess signal--either 4-20 ma or 0-10 volts. You then run your ultra in velocity mode RPM/Volt and reverse it when you want via one of the digital inputs. If your master encoder is not quadrature, you'll be forced into something like this.