Deckel FP2NC X axis run away
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  1. #1
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    Default Deckel FP2NC X axis run away

    Newbie on the FP2NC with Dialog 2 control.
    See if you can point me in the right diagnostic direction.
    When I start up in mode 5 the X axis moves by itself.
    Glass scales on X and Z axis were rebuilt by Heidenheim service.
    I have switched the Dialog axis Cards with the Y axis (reconfigured the Switches) - no change
    switched both Bosch drive cards with the y axis drivers - no change
    swapped the Tach generators between x and y axis - No change.
    What else can it be?
    wiring?

    When it moves it is not rapid movements...slow steady 20 IMP (estimated)

    Michael

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    Possibly the Axis movement pushbutton switch on the main operator console is stuck or gone bad, maybe shorted, or you have a bad relay (faulted in the closed position) controlling the servo motor. When you enable the machine and the axis starts moving- what happens if you change the Mode Selector from Mode 5 to Mode 4?

    What happens if you press the Center red stop button located between the green X+ and X- buttons?

    Suggest you start with the console pushbutton (the switch consists of 2 major assemblies- the top/operator and the switch proper which is attached to the console circuit board which is accessed by loosening the DZUS fasteners under the console and lifting the control panel on it's hinge.

    On an FP4NC, there are 2 relays that control the X servo motor, K7 and K17-not sure if its the same for an FP2NC and may vary depending on year and the particular build.

    Not sure if brushes can cause this but I would check them anyway. Hard to tell if you have a software issue or an electrical issue, based on your description it's possible but probably not likely that there is a fault in the PC.

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    Was everything working properly before you had the scales rebuilt?
    Is this a new machine to you? (was it fine, then it was not?)
    Does the CRT read in the proper direction when the "X" is moving?
    As the table moves away from the operators side of the machine the move should read "Plus"
    Can you affect the speed of the move by turning down the feed over ride? If you turn the over ride to "0" will the movement stop?
    Is it always moving in the same direction? Will it change direction if you engage the feed button in the opposite direction?
    Can you jog the axis using mode 4? Will the slide move with each engagement of the "X" axis push button...will it move in the correct direction relative to the button pushed (+,-)?

    Are you sure that you have the "X" axis scale installed in the correct direction?
    Cheers Ross

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    Okay,
    here is some more hints in this trouble shooting.

    mode #5 x axis moves away from the control panel. Moves left as your at the front of the machine.
    The Metal scale on the indicates 2" at the start then moves to 4" inches.

    Switching to mode #4 does nothing axis still moves. red stop button does nothing.
    Feedrate overide has no effect on the speed.

    starting the machine up with the X axis hand wheel out (engaged) machine does not move

    Control reads more X axis negative value the further is goes. Which is opposite that Ross has stated.

    The machine is a FP2NC with the rare C axis rotary table 2038 serial 800-0555. This gives me some problems on start up as the encode is unreliable.

    Did I mention This is running off a phase converter? Voltage to the machine is between 382-384V

    Push buttons X+ , X- Y+, Y-, Z+, Z- red stop button are repeatable.

    the machine is new to me never seen it run. I bought knowing the x axis was a problem.

    Is the X axis scale in backwards?

    I appreciate your help!

    Michael

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    ross,
    I don't see how the glass scale could be in backwards. The cable would not be routed correctly.
    Are you saying that the rebuilder flipped the read head around backwards?
    Michael

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    Probably not in backwards but pretty sure there is a DIP switch on the axis board to set the scale direction.

    Is the machine "stuck" in Mode 5? What happens if you turn off the machine using the red "control off" push button, switch the Mode selector to Mode 16 and then enable the machine? Does the screen display Mode 16, or stay at Mode 5? Does the X axis still start moving on it's own even in Mode 16?

    Do you have the "hot" leg from your rotary converter wired to the center of the big transformer in the outboard electrical cabinet?

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    Have you checked voltage on the Bosch drive +/- 10V inputs? With the wires from the Dialog connected and disconnected, to see where the command to move comes from

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    I moved the Generated Phase to another leg no change.

    Mode 5 X axis starts moving Trips out at -32.977 and Position error 08 is in the highlighted box.

    Switch it to mode 16 and I see this:

    Si Sys 931 01
    P01 Meter Sys 931 02
    24063 Rest 16 CNC 931 04 DNV

    note at the bottom of screen says 16 turn the nob and the mode changes

    where are the 10V +/- signals from the dialog to the drive
    Is that X11.1 & X11.2 or X12 bit 6,7,8?
    Michael

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    there should be a diagram on the Bosch drive, looks like this:
    bosch-tr25.jpg

    X11 X21 X31 are the axis, pins 1 and 2 on each are the input signals from the control, disconnect those wires from the X11 connector (I presume that is the X axis on your machine) and turn on the machine, see if it still moves by itself, and you can also put a multimeter on those wires you disconnected from the connector, set on V and check what it reads

    because you said you exchanged the boards in the Bosch drive from another axis and yet it still moved, I suspect there is an incoming signal that tells it to move, and the problem is not in on the drive board itself, the puzzling bit is that you also say that that you switched the Dialog boards and it still moved, but better to start somewhere, disconnect the X11.1 and X11.2 and see if that makes it stop moving

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    Disconnected X11.1 & 2, put a DMM on these two wires to check for the signal.
    Started up in mode 5, hydraulic pump runs then machine shouts down. No commanded signal is seen.
    tried DC and AC settings very residual readings 0.001MV

    Pulled out x axis handle, restarted machine. Hydraulics run and then shut off after pressure is reached.
    Machine is idling. push the Handwheel back in. press and hold the job button, move y axis and z axis.
    Push x axis and the machine shuts down after a second. the meter on x11.1 & 2 goes to 3V DC then machine stops. I marked the motor position and noticed that it had moved about 5 degrees before machine shut off.

    Possibly the axis motor?

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    that signal is DC, 0V means the control doesn't want to move that axis, positive or negative voltage means the control tells to run the motor in forwards or backwards and how fast, the higher the voltage the quicker it is supposed to spin - that is the basic description of the +/-10V interface

    if I understand correctly what you did then - still with the wires disconnected, you enabled the axis, tried to make it move, the voltage raised to 3V and the control errored out, which is correct behavior, the control is supposed to send a signal (+/- voltage gradual rise) to initiate the axis movement, and will keep increasing that voltage till it reaches preset value (which seems to be those 3V in your case) and not seeing any movement will shut down and display error, which is all fine

    now, put the signal wires back into the Bosch drive with additional leads to connect the multimeter, restart the machine and look what the voltage is when the axis moves "by itself"

    the fact that the motor moved somewhat during this time is more or less normal, tuning might be little off because of the aging of components on the amp board which is all fine, can deal with that later

    the important bit now is to check whether there is input to the drive to tell it to move when it is "running away", right now it seems to me that the drive itself isn't at fault, because without any input it hasn't drifted by itself

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    Could there be a ground loop issue on a shielded cable where the ground is connected on both sides? jim

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    If you try and move the axis with the DC lines removed the control will fault and go to E-stop....
    Reason is that the control expects to see the scale move...and expects to see an output from the tachometer...with the control voltage lines pulled you get no movement and that causes a fault

    I am still suspicious of the scale being in backwards...It moves because the axis is trying to reach equilibrium (servo hunting) and since the feedback is backwards it can't get there..The reverse reading display is a clue.
    You stated that the the display shows a minus(-) value but the table is moving where the hand wheel is moving away from the control station.. If this is this correct then the slide is moving opposite from what its displaying.
    You have swapped the NZP boards and you were careful to set all the DIP switches as per the orange book settings for the specific axis.
    .
    Seems that if the control was outputting an erroneous move command(something wrong with the logic side) the display would still read the axis move direction correctly! Its not, which suggests that the feedback portion of the control loop is at fault. (Scale or Tach)

    I had an FP2NC that had the output cable from the "X" read head running out the "X" minus direction (away from the operator) and was looped back under the read head to exit the direction one would think was correct
    (toward the operators side).

    Not seen this done since, but it was the way this machine came to me and it is the way it worked ...can't explain the why, just know it was that way.

    Other thing to check is the polarity of the tach leads....Believe reversed tach leads can cause this sort of symptom....(not sure about the reversed CRT reading, but runaway,sure)

    Additional thought: If you set the machine to mode1 (hand operation) and pull out the "X" axis hand wheel, and move it by hand using that hand wheel, is the direction of the move correct..that is, if the slide moves away from the operators station does the CRT display a plus(+) or minus (-) move...is it reading the same as when it is running away in mode 5....In hand wheel mode, the control is out of the loop, just the scale is in play.

    Cheers Ross

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    Tacho cables across? I remember reading that if the tacho cables are in wrong terminals it causes axis runaway.

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    Harri89 - I switched the tach cables... Mode 5 power on... X axis runs away in rapid mode. Took estop to abort the crash. so that's not it!

    JZ79 - Put jumpers on X11.1 & 2 Voltage increases to 1.25 DC when the axis moves at 20 IPM.

    Ross - In MDI mode 1, start machine moving table away from operators station - X axis is negative value.
    So, you think that the repaired glass slide is wired "out of phase"?

    I really appreciate the Help! you Guys are awesome!

    Michael

    Another add on... The Company I bought this machine from had the same glass scale replaced. Work was done by the Deckel Doctor... when he was still doing this kind of work. They couldn't get it running and that's why I ended up with the machine. Machine was dead for 4 years...Before anybody asks... I changed out all batteries on all boards and under the control panel.

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    It looks like that in that Mode5 the control is telling the X axis to move for some reason, that is what that 1.25V is on those leads, and if I understand what you did previously, then the Bosch drive didn't move the axis by itself (those few degrees don't count) when those leads were disconnected, that rules out problems with the drive itself as far as I can tell.

    To be 100% sure that the drive is acting correctly, you could use external adjustable power supply to provide voltage to those leads and see if the drive follows your commands - increases/decreases the motor speed proportionally to the supplied voltage, reverse polarity to move it in the other direction.

    This is as far as I can help, I'm not familiar with Dialog controls to help track the problem further in it.

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    Thanks JZ79 - you have been very helpful so far.

    Ross - I tried to flip the scale. But there is no room for the cable to wrap back around. The X axis castings is machined with 0.020 Clearance for everything. No possible way to get the cable thru.
    Anybody got a pinout of the glass scale plug wiring? If I swap the leads around it should do that same thing right?
    Michael

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    Quote Originally Posted by kingmichael427 View Post
    Harri89 - I switched the tach cables... Mode 5 power on... X axis runs away in rapid mode. Took estop to abort the crash. so that's not it!

    Ok tach verified, that is good. Runaway with leads reversed is normal.

    JZ79 - Put jumpers on X11.1 & 2 Voltage increases to 1.25 DC when the axis moves at 20 IPM.

    I think this is normal when starting with servos enabled (modes 4,5 6,7,8,&9) Think the control sends out a small move and waits for the servos to correct....In normal operation the servos "hunt" constantly
    Moving ever so slightly then correcting to hold position, since your position is inverted think it is hunting using the full travel of the slide and never gets there.

    Ross - In MDI mode 1, start machine moving table away from operators station - X axis is negative value.
    So, you think that the repaired glass slide is wired "out of phase"?

    Think something is wrong with either the wiring or the scale....The signs point to something in the feed back side of the control.

    I really appreciate the Help! you Guys are awesome!

    Michael

    Another add on... The Company I bought this machine from had the same glass scale replaced. Work was done by the Deckel Doctor... when he was still doing this kind of work. They couldn't get it running and that's why I ended up with the machine. Machine was dead for 4 years...Before anybody asks... I changed out all batteries on all boards and under the control panel.
    More evidence.....They changed the scale and the machine has not run correctly since. Scales are impossible to assemble backwards, the read heads can only be installed in one direction relative to the housing....
    But other things can give directional issues. Cable could be messed up or the output from the scale might be inverted.....As i said i have seen one machine that had the read head and therefore the scale
    installed as what i would define as "backwards"
    Not difficult to try flipping the scale. No need to bind up all the cables and such, just turn it around and try it.

    Cheers Ross

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    I do not know this control but there should be a parameter available to change counting direction on the scale, rather than moving it physically

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    Quote Originally Posted by jz79 View Post

    To be 100% sure that the drive is acting correctly, you could use external adjustable power supply to provide voltage to those leads and see if the drive follows your commands - increases/decreases the motor speed proportionally to the supplied voltage, reverse polarity to move it in the other direction.
    Without a power supply available, you can do it with AA cells at 1.5V increments.

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