DMC1 Door Learn- Cycling doors

I have a DMC 1 that has started intermittently cycling its doors on slow speed doing a learn trip. This is becoming more frequent. Looking towards door board/encoder. Any thoughts? Any similar issues?

What have you checked so far? Have you plugged up your tool yet? Is it saving the pulse count?

I've seen some DMC'S that will run doors slow just because of interlock issues, or the dcl not set correctly and it's bumping the pickup. Sometimes the doors will slightly roll back when sitting idle and bump the pickup, even buildup on the end of the rail has caused issues for me in the past. I've also had intermittent issues with some of the HW relays, even a bad wiring job where the door motor leads are pushed into the connector. I've seen jobs where the door board wasn't pushed all the way down on its mounting tabs and it cause issues.

Check DO PAR 001.

Have you re learned the encoder pulse count? See if the new count is different than what you have now

Before doing a lot of problem solving, you may try replacing all the Belts. A lot of times this will take care of pulse count problems. Replace belts do a learn, it may help.

Don't know what the outcome was here, but those stupid plastic collars for DOL/DCL will eventually crack apart causing the collar to shift on the shaft thus no magnetic effect to the sensor. This will cause the doors to cycle slow.

I had the same problem with my DMC. It was the DCL limit not making properly.

Hey Rollaway
Got an update for us? You got all kinds of good advice, but you've flatlined.

Wow has it been this long? Where have i been? What have I been doing? Service work, safety tests, replacing a step chain and steps on an escalator, the usual. 1 LR and 2 mechanics here so we do EVERYTHING. Maintenance, service, construction, surveys, sales, customer visits. Its a juggling game. But they leave us alone so I'll never complain.

I'm thinking it was the cracked DCL limit too, replacing that calmed it down but then later found a bad safety edge cable causing it to intermittently open at regular speed too, and the customer wasn't clear on the speed differences, just that it was opening on it's own. A coincidence of 2 separate events causing very similar occurrences.

Going to throw a few of those collars in the van!


Also was recommended that it was important to do a door learn from the software on the laptop. My assumption is that the door software is programmed to do a learn on its own, because the pulse count it stored was identical to the pulse count i initiated from the computer.

While i was playing around I found a feature in the CLC parameter list that said:

Predictive Maintenance

Any body have any idea what this could possibly mean? Its been on my mind for awhile. We have a unit built by a (now out of business) local company with an off-the-shelf PLC and it was programmed to require a reset procedure every 6 months. Which always ended up in a callback.

Don't know about the "Predictive Maintenance", but glad you have your trouble figured out. The bad SE cable can be elusive as the signal fires on/off so quickly, the Fast Tool (or maybe even the Freedom Tool) can't always display it. Huh...it's been awhile, but I thought the door scan had to be saved after the set up procedure was completed, then you would modify the open and close profiles for your personal liking.

Anyhow, time tells all on these intermittent troubles, but thanks for the update!

This was the cause of my cycling ghost. When I replace the belts on a DMC operator, I always use the 3VX630 belt, which has cogs in it. It has a much better grip than the smooth surface on the 3V630. The problem arises when the pulse count from DCL to DOL is inconsistent, so it will slowly cycle the doors to redetermine a correct count. If your doors run fast like Star Trek doors, chances are there will be some slippage and then the ghost comes back.

I've never seen the predictive maintenance option on a DMC. That sounds like the line of code placed in the Ascension 2000 software which is a run counter, guaranteed to cause a shutdown after a certain amount of runs. What a pain that is to us and an annoyance to the customer.