Ml 1500 problems

magicsmoke

Member
magicsmoke
Join Date
Aug 2007
Location
Minnesota
Posts
110
I have a Ml 1500 1764-28bxb with one 1769-IQ16 input card and one 1769-OB16 output card.

Here's my problem, over the last couple of months for some reason the plc blow's away the program faults the plc and I have to go and reset the fault and reload the program. I've been checking all the forms and found that this is more than likely a noise issue.

So I ran a bigger ground to the Plc the biggest wire that would fit in the wire terminal and grounded it to the ground bar where the main power come's in. This took care of the problem for a week.

Did some more reseach and installed a Islatrol elite filter on the 110 side before the 24vdc power supply(AB 1606 XLP 95E)that powers up the Plc. This took care of the problem for a couple of week's then is started again not as often as before maybe once a week.

This is driving me crazy and I ran out of idea's this machine as been production for 2 years never seen any problem's the first year. We have one more of this machine's and it run's great and it's only 10 feet away from this one.

If any one can help I would greatly appreciate it before I pull all my hair out.

Magicsmoke
 
not a solution magic, but.... if you can install a memory module to the plc and have it load from EPROM if the plc faults would at least get you to the point where you are not dumping in the program on a regular basis.
 
Do you have a scope available? or any method to check power quality and grounding?

Are you certain there is only 1 ground and that it connects to the ground at the main power source.
 
ML in general need snubbers on the inductive loads... not at the card across the load as per pages 1-8 thru 1-10 of 1761-6.3 ML1000 user manual... when outputs make or break even momentarily they throw a nasty spike back down the wire towards the PLC.

once you add the snubbers you probably wont need the input filter anymore

( filter on input line cuts noise in and noise out on the input grid but not the output spikes )
 
Check the connections of the 1769 I/O. Sometimes when a faulty connection exists on the backplane, this type of error occurs. I saw it before and it was a problem on a 1746 backplane.
 
rsdoran,
I can get my hand's on a scope, I have checked the ground it goes all the way back to the busway.

Magic 8 Ball,
Why would one machine need it and the other doesn't.
 
Back in the late 90's I was working at a plant that put in a system they took out of a plant corporate closed. In the process of the move the engineer decided to put the plc under the bag orienter, pusher, and pallet loading door, needless to say there was a lot of vibration. The PLC5 cards would vibrate loose and fault the processor, almost forgot about that till the previous post.
 
I could check that out once again. At one point I've tried replacing the plc from the other machine that hasn't had any problem's. And still got the same problem.
 
variations in components used in manufacturing a cold solder joint vs a good one...a floating ground...add the snubbers for longer output card life as well...it really does work
 
you have to match up the load to the snubber both voltage and amperage wise... a 5 amp is ok on a 3 amp load but dont go the other way around.

answerbase doc 19965 says both 24 volt 700R and 24 volt 700RM use the same snubber 199-FSMA9 as per proposal works
 
Last edited:
I had a problem very simular to this on a compact logix.

The PLC would run for days weeks or months, then of course in the middle of the night it would fault. The only thing that would bring it back to life was seperate the power supply from the processor and I/O cards. Then I would have to re-load the program because it would be gone.

It turned out to be a broken analog sensor going back to an analog input card. It seems a production person broke the sensor, stuck it back together, then put a little tape around it. Apparently it took a while for the first fault to happen. By the the sensor had become covered with some production by product and could not be seen anymore.
 
First i want to know one thing
wat about PLC error code & description.
according to the error find the solution.
Don't reset & download the program , first u see the error code & check that rung/file.


magicsmoke said:
I have a Ml 1500 1764-28bxb with one 1769-IQ16 input card and one 1769-OB16 output card.

Here's my problem, over the last couple of months for some reason the plc blow's away the program faults the plc and I have to go and reset the fault and reload the program. I've been checking all the forms and found that this is more than likely a noise issue.

So I ran a bigger ground to the Plc the biggest wire that would fit in the wire terminal and grounded it to the ground bar where the main power come's in. This took care of the problem for a week.

Did some more reseach and installed a Islatrol elite filter on the 110 side before the 24vdc power supply(AB 1606 XLP 95E)that powers up the Plc. This took care of the problem for a couple of week's then is started again not as often as before maybe once a week.

This is driving me crazy and I ran out of idea's this machine as been production for 2 years never seen any problem's the first year. We have one more of this machine's and it run's great and it's only 10 feet away from this one.

If any one can help I would greatly appreciate it before I pull all my hair out.

Magicsmoke
Click to expand...
 

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