I have a situation with a customer, they are using AcoposMulti with their machine and recently they have received an error about the Lag error Stop Limit, specifically: Error 4007 Lag Error Stop Limit exceeded. This error shows during operation and not while the controller is turning on or during comissioning.
I’m aware that this error should not be appearing during operation, since it was adjusted by the manufacturer. I only had seen this error during the comissioning and autotunning.
I’ve already check the causes and remedy list from automation help, soon I will be able to check the SDM, maybe I can see any other error number and help me to isolate the issue and reduce the list of causes.
does anyone have seen this behavior before? any advice to resolve this error?
I can only give the advice already mentioned in the help article you linked: some values are either not matching the machine or the machine now has a harder time moving than before. Lag error is the difference between set and actual position and there must be a reason for it to trigger.
The “not while the controller is turning on” part is usually normal, since you have a set position of “here” and the axis stays “here” when turning on - so no differences in set and actual position.
The " This error shows during operation and not while the controller is turning on or during comissioning." and “I only had seen this error during the comissioning and autotunning.” are contradictory to me, though.
Hello @michael_w I´m sorry if you misunderstood me.
The " This error shows during operation and not while the controller is turning on or during comissioning." I was trying to explain tha the Customer is getting this error during the machine operation. For this reason the customer contact us as a support. Also, I was clarifying that this is not a comissioning
The “I only had seen this error during the comissioning and autotunning.” I was trying to explain that ME personally only had seen the 4007 lag error, during a comissioning and autotuning, I had never seen this error during operation, until yesterday.
Thank you for your feedback, I’ll be more clear in future posts.
The “the machine now has a harder time moving than before“ you mean that they may be some mechanical wear? that could be a reason of why the lag error increased. Also, I was thinking maybe the encoder is is damaged
Hi @Salvador_Flores ,
Unfortunately, autotuning has spoiled us…hehe
In too many cases we don’t spend enough time anymore on axis tuning, and we see quite often issue when the machine is in the production.
We have lag error in different cases:
Sizing of the motor not correct
Sizing the drive not correct
there is room for improvement on the axis tuning
the builder saved money on the design of the machine and his expectations are too high
Mechanical issue, this is unfortunately more common than we expect:
In all of those points servo loop optimizer is great tool, now since mapp Motion 6.5 it’s integrated on mapp Cockpit on the commissioning pages (thanks so much to single axis control R&D).
Your customer asked your help and the only way you can help him is collecting more data (SLO position/SLO speed/trace key ParIDs), review them and provide guidelines.
At the moment (I don’t know in the future) in the Community we don’t do deep investigation so I recommend to call our Support in Atlanta, but before that be sure you have all this information:
For example if in the motion transmission we have bend or gear you have totally different reaction on the system.
5) s/n of the motor
6) s/n of the drive
7) Few description of the axis: linear/rotary (+resolution: for example 100 Ax units is 1 degree), horizontal/vertical axis, gearbox…
8) axis limit parameters: max vel/acc, t_jolt
9) A trace with trigger enabled when you have axis error with a little bit of history with basic ParIDs:
112: CTRL Position controller: Lag error
113: CTRL Position controller: Set position
114: CTRL Position controller: Set speed
250: CTRL Speed: Set speed
1159: CTRL Speed: Speed error
213: CTRL Current: Set stator current quadrature component
I support the suggestions to get more data. The important ParIDs got listed. Focus on the current (torque) and lagerror.
This is the nice part of a servo drive and motor that we can diagnose the movement in a great way.
I once had a costomer with sporadic lag errors while moving, i immediate said this is a dieing gearbox, sporadicaly blocking.
The coustomer told this is not possible,… So we did made Traces and could show that on every movement at the same position there was a huge torque peak. Some times the axis made it just below the lag limit. And some times the axis did not mad it. So the error was not sporadic ist was just a wear on the mechanic.
This is were traces are a huge benefit.
So if there is a axis with an issue. Go there make some diagnostics. Saves much time.
I never saw/heared of an lag error based on encoder error. There are a lot of encoder supervisions. If you have a defective Encoder you will get a Enocder error in some way. I would bet.
If a trace is not clear for you, share it here. We will have a look together.
