A/B Motion Axis Gearing (MAG)

Need some help, have a project with a tap, have it set up to do MAM with a slide axis and then the tap spindle takes over as the master with a MAG; next MAM, MAS which un-links the two servos and MAM to home with the slide axis.
My problem is I can repeatedly tap six holes flawlessly and on the seventh hole when the tap stops and goes to reverse it faults. The error I get is Feedback Error past Factory Limit, also noticed I have 6 data packet loss each time this happens. Tried everything I know even setting the number larger for how many packets I can miss. ANYONE HAVE ANY IDEA, thank you in advance.

what hardware are you using? Model numbers and connections

What version of software are you using?


From the instruction you are using (MAM) i an a$$uming you are on the control logix platform
How are you your axis set up rotary? or linear?

I would be surprised if the packet loss is related to the feedback fault, but it can't be discounted.

Is it always the spindle servo that faults ? What is the exact fault code and where are you reading it ?

The first thing I would do is try to trend the feedback error during the successful tapping cycles, to see if it's increasing on each one or if it differs on the last one.

I m using a Controllogix L33ERM 2198 Kinetix 5500 drives with VPL servo motor, e-net from the controller port through the drives. The fault is read from the axis properties fault log. Feedback Error Factory Limit. The fault is always in the spindle axis, just after motion axis stop when it goes to reverse. What I do not understand is it will tap six holes perfect and always does it on the seventh hole. Command order is as follows: MAM,(slide axis rotary) MAG, spindle servo takes over) MAM, MAS, MAM(to go home) I am using RSLogix Studio 5000 Ver. 21 everything has been flashed correctly. Have not been able to put my finger on this problem so far, any help would be welcome.

from the user manual motion-rm003 "Integrated Motion on the EtherNet/IP Network"

45 E Feedback Data Loss FL The number of consecutive missed or corrupted serial data packets over the serial data channel from a feedback device has exceeded the Feedback Data Loss Factory Limit. The offending feedback channel is encoded in the associated Fault/Alarm Sub Code.

Click to expand...

I would be checking your ethernet - what else is connected? try isolating the ethernet from the factory LAN to see if it still occurs.

Trying to give you some other ideas (which from what you have done I think that you already have)

What are the errors in MAM when it occurs ?
Do you loose all of the axes or only that one?
Can you post a screen shot with the offending axis selected and the connection and fault status on the screen?

I see that you are new to RS logix - any chance that you could post your program ?
I'm looking for the Axis setup and how you program MAM, MAG and MAS

Excellent research, Michael. Thanks for pointing to the likely error code; I was pursuing the wrong interpretation of "feedback error" as being "following error".

If the error is really E45, Feedback Data Loss Factory Limit, then the "number of error packets" isn't on the Ethernet between the Kinetix 5500 and the CompactLogix, but rather on the digital feedback channel between the Kinetix 5500 and the VPL motor.

The six data packets lost and the six successful actions does seem to be a suspiciously high degree of correlation.

I wonder if each of the MAS instructions is resulting in a single "packet lost" in the feedback for the spindle, and that they're eventually stacking up ?

Can you run a trend on that feedback packet loss value to see if it goes up by one each cycle, or if it jumps from 0 to 6 all of a sudden ?

Michael an Ken,
Thanks I will check your suspicions out and get back with you. Yes I m new, this is my third project with RSLogix 5k. There is so little time and so much to learn, when doing these projects. My boss is so cheap he will not pay for tech support so I m on my on most of the time, so I really appreciate everyone's help.
I have five axis drives using linear star topology.
I did have the enet cables ran close to the line filter for the drives, thought this may be the problem. Moved them and the problem still presented itself as before. I have been told to work Sunday so I will do what you asked and see where it leads. Have a great 4th and be safe. Again thanks for the help.

oldnerd said:

Need some help, have a project with a tap, have it set up to do MAM with a slide axis and then the tap spindle takes over as the master with a MAG; next MAM, MAS which un-links the two servos and MAM to home with the slide axis.
My problem is I can repeatedly tap six holes flawlessly and on the seventh hole when the tap stops and goes to reverse it faults. The error I get is Feedback Error past Factory Limit, also noticed I have 6 data packet loss each time this happens. Tried everything I know even setting the number larger for how many packets I can miss. ANYONE HAVE ANY IDEA, thank you in advance.

Click to expand...

I think your issue has to do with setting your software limits-end stops and such especially for linear axis.
I believe your "software limits" for the tap axis kicking in.
Try to disable the limits and see if you can tap more than 6 holes.

The words "limit", "feedback", "error" and "packet" all seem to indicate different things to different readers, so get as much detail as you can about the exact error codes.

If the fault is really a "feedback loss", it's similar to how a drive would fault if you disconnected the servo feedback encoder. I've battled many encoder faults of this type when the encoder signal passes through a field-installed connector or runs in parallel with long motor power cables.

These are the Kinetix 5500 with VP series motors, which have a single cable from the drive to the motor that carries the power conductors, the brake conductors, and a digital encoder feedback signal called Hiperface Digital Servo Link.

Hiperface DSL is built to be resistant to noise, but it's still possible for the feedback signal to be disrupted, which is why there's a "factory limit" for lost packets in the feedback cable.

Found the problem today, I ran a separate ground wire out to the ground rod for the building and connected it, from the rod to the panel ground bar. No more problem with packet loss. Also the packet loss was accumulative. Thank for the help, and getting my thinking going in the right direction.

similar problem

Had a similar problem, except that I got the fault immediately upon issuing a MSO. Thank you for the ground solution. My problem was that the motor cable wasn't grounded to the inverter at all. As soon as I clamped the ground correctly my faults went away.