Film-Tech Forum ARCHIVE: Clearing/Resetting ADC LogiStop Memory

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Posted by Manny Knowles (Member # 1171) on 10-29-2010, 07:20 PM:

Our brand-new LogiStops are acting up. We've got three of them.

They're not remembering where the "zero" position is.

The position is off by different amounts each time. And it's not coast or drift or whatever -- it's off by hundreds -- like 680-something one time.

Same applies to programmed stops. All over the map.

We followed the procedure for re-setting the counter and clearing the stops but it does not work. We tried it like it says in the manual. Nothing. We tried it a different way (as described by customer service). Nothing.

What's up?

I noticed some hex switches and dip switches. Could something be wrong there???

Posted by Tony Bandiera Jr (Member # 2365) on 10-29-2010, 07:58 PM:

Hey Manny, I have a bunch of those and the one thing I have found to keep the stops right is that your FIRST programmed stop MUST be run in the FORWARD direction (the motor's forward, which could be in or out depending on the way the rigging was done.)

For example, say that forward on your motor closes the masking in. To set the stops, you would run the masking OUT to the mechanical limits, then run IN to your desired stop point. Try not to overshoot and go and forth. Then I always do ENTER, (Stop #), ENTER.

I tend to set ALL my stops in that manner and they tend to stay put.

The motor at UC Irvine was set that way 13 years ago and has yet to lose a stop.

Those motors that I have had issues with rarely lose ALL the stops, so if yours are losing ALL of the stops I would make sure your rigging isn't slipping.

The "all over the map" tends to tell me there is an issue with the rigging. The motors that I have had stops lost on, they are repeatable, i.e. they aren't in the right spot BUT they keep going to the same spot every time.

Check the sprockets on the encoder (the mini chain drive) and the main sprocket to make sure they aren't slipping.

If your rigging is being driven by a pulley then that's the problem as a pulley drive WILL slip. Masking should always be driven by a length of chain and sprocket, while drapes should be driven with a large drum.

Posted by Manny Knowles (Member # 1171) on 10-29-2010, 08:52 PM:

The rigging is steel cable in a nylon jacket.

I tried your method of pressing ENTER <number> ENTER and that seems to work.

We also set the coast values (fwd and rev) based on how far off it was the first few tries.

Now it's landing much closer to the target value +/- 12, which is better than being off by hundreds.

As for the physical position: It's "about the same" every time now. A difference of +/- 12 does not translate to very much movement at all.

One motor down, 2 to go -- we'll play with those in the morning.

THANKS! [beer]

NEXT QUESTION -- How do you clear the memory and reset the counter to zero? That will help with the other 2 motors.

Posted by Tony Bandiera Jr (Member # 2365) on 11-08-2010, 12:55 PM:

Never had to do a total wipe of the stops, the method I gave you has always (so far) worked for me. I have yet to get ADC to tell me how to do a total wipe in any event.

To get the counter to zero you would need to disconnect the encoder drive chain and crank it to zero manually..I don't recommend it (and it's totally unnecessary) as you could easily foul things up. It doesn't matter what number you start at for programming, as long as you run in the forward direction to get to the positions you want.

Does your rigging get driven with a length of chain running on a sprocket off the motor, or is the cable directly on a pulley/sheave?

If it's not driven by a length of chain, it will NEVER work right and always be subject to slippage.

Glad the first one seems to be working out.

Posted by Manny Knowles (Member # 1171) on 11-08-2010, 02:30 PM:

I asked about the chain and he said it's just the steel cable -- no chain -- but it's never come up as a problem for them. So we'll see...

The installer hand cranked back to zero and used your method to enter the stops. So far so good...

Thanks for the help! [beer]