ABB S4 controller - Welding problem

    Hello all,


    Maybe someone can help me with an issue one of my clients has run into.


    They are using an old ABB robot, S4 controller for arc welding with an old Fronius Power Source.


    What's happening is that, randomly, one of the welds comes out much smaller than it should be, as if the amps drop suddenly, or the speed increases drastically.


    We've had ABB check the robot, and it got a green bill of health.

    We've had FRONIUS replace the welding equipment off a different robot. The error persisted.


    The only think I can think of is that the AO controlling the weld parameters may be malfunctioning. The issue is that whatever happens, doesn't happen regularly. It's random in the extreme and any weld can be bad.


    But, considering the age of the equipment, I have no idea where to even check for that.


    Does anyone have any suggestions or ideas as to what this may be? I've already contacted all my contacts that may have had, at one point, a robot as old as that, but I couldn't manage to find any relevant help.

    Quote from ClaudiuA

    What's happening is that, randomly, one of the welds comes out much smaller than it should be, as if the amps drop suddenly, or the speed increases drastically.

    Can you give more detail? Does the weld stay small until the ArcL\Off and then what happens? Do the smaller welds still give good penetration?


    For the analog, is a DSQC209 or a Combi board (DSQC224/315)? Are the analog signals in a shielded cable and away from high current cables such as weld, motor, power?


    Have you tried creating new SEAM data and using that? Is it possible it stops weaving to cause the weld widths to be smaller?

    I would pull the weld cables and thoroughly inspect, especially if there's a positioner/turntable involved.

    Hello,


    Yes, the weld stay small until the ArcL\Off instruction. They are not using any weaving for their welds. Seam Data changes for some welds, but even those have a chance at the same error. It's never more than ONE weld per part that comes out like that - this is probably a coincidence.

    ABB Romania had previously separated all the cables to avoid exactly the issue of interference between power and signal. Doesn't seem to have helped any.

    Yes, there is a positioner and turntable involved.


    I have no idea the board. My dumbass self looked in the wrong cabinet for the boards...

    Have you ruled out the wire path by checking the conduit & fittings, the feed roller tension, replaced the liner & tip, etc.

    If your using a separate wire sense cable - check that.

    If the Fronius has a wire buffer, make sure the sensor is operating properly and the connection secure.

    If it has a Robacta drive, make sure it is not cracked - although my experience is that it slows the wire and causes wire burnt to the tip.

    Remove all weld cable connections, verify they are clean and installed directly to lugs & ground points - no washers or other things in between.

    Make sure weld cables going thru the positioner and table are not worn thru in in spots.

    If the positioner & table have ground brushes, check those.


    While it happens, does the welder show proper voltage and current?

    Which Fronius interface and welder are you using?

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