Axis 4 making a noise.

[Mike0027]

Hi All,

When I bring in the drives the robot is quiet, but if I try to move one of the axis a screaming noise is emitted by the axis 4 motor. If I try to jog axis 4 the motor makes a grinding type of noise.
Also it seems that if I jog axis 4, axis 6 is turning.
The robot is a KR C1 125_L90. I have changed the machine data to a KR C1 150_L120 but this made no difference.

Any ideas?

Thanks

Mike

[markopo]

Hello Mike.
For the first my question is that You checked by Hz-meter tightness of belts ? For last 2 axies ?
Second You have to dismount wrist to check cardan gears sealings and loosy between motor and wrist.
You have to detect where do You have broken sealing etc.
For third for me if You turn ax 4 that You notice that 6 is turning.
For me that is possible because of loosy on gears or sealings.
Maybe problems with motors ? with brakes ? But that is very rare I think.

Marek.

[Mike0027]

Hi Marek

I have removed the  axis 4 motor from the robot and jogged that motor and it still makes a noise, the gearboxes seem smooth.I also swapped encoder and power cables between axis 4 and 6, and when I jog it the same screaming noise comes from the axis 6 motor so it looks like it might have something to do with the drives.There are no errors showing up on the KCP.The problem started after I left the robot powered up for 8 hours or so to try and charge the batteries.

Thanks for the help so far.

Regards

 mike

[Industrialrobotix]

Before you rule on the drives, make sure that the brake is releasing...I have run into this with other robots - i.e. the motor will make an ugly noise if the brake doesnt release...but it sometimes will not amp out the drive and will allow it to operate....it will eventually overheat...  Could be a harness issue...

[mechrob]

This can be RDC-problem. This is the card inside the black box (X02) on the foot of the robot.
You can try to adjust the RDC-values. I can't explain you exactly how to do it, but I'm sure someone else here can explain. (Setup, service, DSE-RDW,... I'm not really sure if that's 100% correct but maybe it will help you get started)
When that doesn't work you can try to exchange the card.
You would be suprised how many supposed "mechanical problems" are just electronical problems.
I really should try that before you would try any other mechanical solutions. Hopefully someone can explain you exactly how to make these adjustments.
Also check if the machine- and load-data is correct.

[SkyeFire]

Hm.  If whatever servo motor you plug into the A4 cables makes this noise, it does sound like a brake problem with the servo amp.  If this were a KRC2, I would recommend swapping servo modules in the cabinet, but on a kRC1 that's not an option.

Hm.  With the motor dismounted, keep your hand on it and do a tiny jog with one of the other axes, just enough to make the brakes release.  If the brakes are working at all, you should be able to feel them "thump" inside the motor.  If you can't feel the brake release, then that's definitely the problem.

Another thing to try, perhaps, is run an o-scope trace of the motor's current and positioning error.  Do this with the motor plugged into the A4 cables, and then repeat with the motor plugged into the A6 cables.  If the A4 brakes aren't releasing properly, you should see a sizable difference in current between the two tests.

[Mike0027]

Hello All

Thanks for all the help so far.

I have checked all the cables etc and they all seem to be OK, but now the robot has a Transmission error DSE-RDW1 fault. Does this mean the RDC card is damaged, is there any way to test the card.
Also every time I boot the robot I have  re enter the robot serial number and correct the machine data version- does this mean anything?


Thanks again

Mike

[optimus_prime]

KRC1 to Robot Encoder Cable can be faulty.
Also RDC,
Try a cold start.
All data like serial no of robot etc, robruntime is stored on RDC.

[SkyeFire]

When encountering RDC-DSE communication issues, the first thing to check is the cable between the cabinet and the robot.  This cable has a large number of small pins crowded into a small circular connector, and if someone pushed the cable into the socket at the wrong rotation, often one or more of the pins can be pushed back into the connector, making for lost or uncertain contact.

Check the male end of the cable, and the male socket on the robot cabinet.  Look for pins that are shorter than the others, or pins that let you push them back into the housing when you push on them (don't push too hard!).

Once you re-enter the robot serial number and machine type, does the Transmission Error go away, or does it stay up and resist being cleared? 

[Mike0027]

Hi All,

I have checked the cable and it seems to be fine. Once I have entered the robot nome the tramsmission error stays up and can't be cleared.

[ellim]

If you had check the cable and everything fine, you should try to change the RDC or DSE. Both of them will cause this error.

[Mike0027]

Hi All,

I have replaced the RDC and the MFC card but now the teach pendant is not working, it stays blank while the controller boots.None of the switches on the teach pendant work either.(key switch of deadman)Please help!

Any ideas?

Regards

Mike

[mechrob]

You changed the MFC-card? I guess you should look there for bad connections.
Is everything connected correctly
Older types of mainboard are very sensitive for dust and corrosion. Try to clean (carefully) the slots and the connections of your MFC-card. You should pay attention for static electricity and wear a ESD-wristband.
It is even possible that the MFC isn't functioning correctly.
Good luck

[Mike0027]

Hi All,

Have connected a monitor to the PC and it is booting up OK. The message window shows an emergency stop but I suppose that's down to the teach pendant not working. Normally when booting you could hear the safety relay's kicking in if you pulled the dead man handle but now there is nothing.Getting a bit frustrated with this robot now.
Any advice would help.

Thanks

Mike

[SkyeFire]

To be honest, it really sounds as if the KCP isn't plugged in.

The reason I say this is that the control and video signals to/from the KCP travel via separate VGA and Interbus wiring inside the KCP cable, and the safety-related signals (key switch, deadman, E-Stop) are carried by individual hard wiring.  For all of these signals to fail at once is very suspicious.  If the KCP circuitry was fried, for example, the deadman and E-Stop would still cause relays to kick inside the controller.

My guess is that while replacing the MFC, you unplugged something and either didn't plug it back in, or somehow plugged it into the wrong socket.  I'm not certain what that could be, though, since the KCP wiring breaks up into separate groups (IBus, VGA, Safety) as soon as the cable enters the controller cabinet, from what I recall. 

If you weren't seeing a good boot-up on the external monitor, my guess would be that a fuse or breaker had been popped. 

Since you don't report seeing any major error messages, I'm guessing that the MFC isn't fried. 

Still, rule of thumb is, if something weird happens to the controller just after you've been mucking about inside, it's probably something you did, possibly without realizing it.  First step would be to re-trace your actions, checking each cable that you moved.  Then poke around and look for anything you could have bumped or disconnected without realizing it.  Especially check all the breakers.