[O-MX45VAE]

I have a kitagawa tt180 trunnion table, and the controller is showing b axis overflow. Any ideas on where to start on this one? Attached is a screen shot.


So I cleaned my machine after milling some plastic. Used a shop vac as i saw recommended and at some point felt a static discharge. Not sure if relevant, but the issues started around this time.

[O-MX45VAE]

Just a bit of additional information. This started about a month ago, and occasionally power cycling would get it to go away. Now it is always throwing an error. I've found references to "- overflow" in the manual, but don't fully understand what they are saying.

Rotary axis with limits and multi-turn rotary table
The relative actual position obtained using the equation on page 23 is displayed as it is. With the
multi-turn rotary table, whether or not relative actual position data is expressed within 0° and 360°
when the NC is reset can be set at NC optional parameter No. 2, bit 1.
When the additional axis is removed with the removable axis specification, “-OVERFLOW” will be
displayed as relative actual position data.

When the relative actual position value is smaller than -99999.999 mm (-9999.9999 inch for
the inch system), “- OVERFLOW’ will be displayed on the display screen.

I cannot rotate the axis, even in manual mode.

[deadlykitten]

hi, i can't help you fix your problem, but i can tell that such things may happen if a rotary axis is being rotated too much among a single sense

i encountered similiar stuff with the C axis on a lathe

somehow you need to reset the encoder, and also you need to check what is causing this

try rotating it in manual, with the ILK button pressed

i don't know for your machine, but on some models is an over-travel-release-switch

in the future, write down the value of the encoder for 0 position, and check later the actual position, so to see if it remains unchanged, or if it changes with 360*

hmm ... try editing the encoder origin ? it may be also linked to other parameters ... about editing the parameters, i would suggest contacting your service suplier; or just write down the actual values, and go experiment : try making the actual position to be equal with encoder origin / kindly

[O-MX45VAE]

Thanks for the reply. The axis is the B axis, which cannot go 360....only about about 110 degrees and -35 degrees

[deadlykitten]

aha ... when the dealer installed the 5th axis, i remember that it got stucked somewhere in the upper or in the lower position. In the end it was a parameter value, but i dont know which one, because they did the research + setting, not me. So maybe you should find some how those parameters, and if all is ok, then maybe some chips got inside your axis.

this is all i can say / kindly

[O-MX45VAE]

I'm very close to 0, so not at end of travel. I'll try opening it up to look for chips...just a but nervous as I havent opened it before.

[OkumaWiz]

If you are getting overflow it either is not reading the encoder or it is out of its range. You may get it it back in range by adding to your PR ZERO OFFSET for the B axis. Also check your stroke end limits for B to make sure they look correct. It’s somewhat of a challenge to find the working range of the absolute encoder so go up by no more than it’s travel limits to avoid overshooting. Sometimes trying to CAL zero may help to locate where it’s at.

Best regards,

On another note, check to see if your Management data card has B values on it and that they match for starters.

[O-MX45VAE]

If you are getting overflow it either is not reading the encoder or it is out of its range. You may get it it back in range by adding to your PR ZERO OFFSET for the B axis. Also check your stroke end limits for B to make sure they look correct. It’s somewhat of a challenge to find the working range of the absolute encoder so go up by no more than it’s travel limits to avoid overshooting. Sometimes trying to CAL zero may help to locate where it’s at.

Best regards,

On another note, check to see if your Management data card has B values on it and that they match for starters.

OK, I think we are on to something. I'm far from knowledgable about changing parameters, but comfortable experimenting. I set the part zero offset for B using Calc, and normal value is 0.6415..it's calculating to -14.5812....so I think this is our issue. Encoder thinks it's near the limit.

Still trying to figure out how to off set this or get it set to where we need it to be. I really appreciate the help.

[deadlykitten]

hello o-mx45vae or whatever your name is

you know, your nick is pretty out of inspiration ....

i first thougth that you have the rotary axis out of bounds, but no ...

after that i thought that your tilted axis is at upper, or lower limit, but no ...

that observation from mr Wizard, about using CALL to locate actual position and compare it with values from data management card is pretty ok, i onestly apreciate that advice

but you are lost at the 0* position for the tilted axis ... you are lost in the middle haha / nice

check this out

https://www.youtube.com/watch?v=4SY-YUR7Vzg

[deadlykitten]

I set the part zero offset for B using Calc, and normal value is 0.6415..it's calculating to -14.5812....so I think this is our issue

how do you know that normal value is 0.6415 ? at 0*, the face of the rotary axis must be paralell to it's base plane, thus with the table of the mill

such determinations are done without using a part, but directly on the 5th axis ...

Still trying to figure out how to off set this or get it set to where we need it to be. I really appreciate the help

put the face of the 5th axis paralel to table

find the parameter for 5th axis B origin : press CALL + enter, after that set upper and lower limit; unfortunately i can't pin point exact parameters, because i don't have a machine like yours / kindly

[OkumaWiz]

Take the difference from the two numbers of where it is supposed to be and where it is and add that number into the Zero Offset (machine) for the B-axis. This will correct the encoder reading without having to reset your stroke end limits.

Best regards,

[deadlykitten]

hello mr Wizard, i looked over that image : pitch error comp range ( line 3 & 4 ) <> travel limits ( line 1 & 2 ); why ? seems to be a big machine, which is "tuned" only in the middle ...

i don't believe that it is ok to edit only the zero offset, without checking also the limits; maybe he will "mirror" his problem, getting from -overflow to +overflow

i believe that is not ok to change only a single parameter, but he should check them all, especially because it is not known what have caused this problem

some parameters are inter-linked, and if one was affected by an error, and a good one is edited so to "fix" that erorr, then let's hope that there are hard limit switches ?

normal value is 0.6415..it's calculating to -14.5812

The axis is the B axis, which cannot go 360....only about about 110 degrees and -35 degrees

I'm very close to 0, so not at end of travel. I'll try opening it up to look for chips...just a but nervous as I havent opened it before

there is a deviation of circa 15* ( 0.64+14.58 ), near 0 position, and a range of -35* +100*; the deviation is inside the range, but yet there is an overflow ?!

even if your advice will work, i am still in doubts / kindly

ps : where is motor city ? i google it, seems to be Detroit : enjoy the ride, and don't forget to deliver 100 floppy drives trailblazer

---

hello mx45vae, i also intended to share some photos with parameters, but they look pretty similar to what mr Wizard shared, and i don't believe that they are ok for your control, which seems a bit old, unless parameter layout is identical, and only graphics is different ? ... try to make some photos or a video with your parameters, maybe someone will spot the exact ones ?

i would go like this :
... measure real tilt angle, relative to base = mill table plane ( let's say it is 3.23* )
... program offset B = 0
... check displayed value, on the screen ( let's say it is 9 )
... encoder origin : CALL + 3.23, or add the difference : now the displayed value should be equal to real value
... now i would check the travel limits

have a nice day

[O-MX45VAE]

Take the difference from the two numbers of where it is supposed to be and where it is and add that number into the Zero Offset (machine) for the B-axis. This will correct the encoder reading without having to reset your stroke end limits.

Best regards,

I did this and now program zero call results in the same number of the machine offset. I'm pretty sure the b axis was at 0 when these issues happened.

Maybe the encoder is so far out of range from being bad that it isn't giving a value?

[O-MX45VAE]

Talked to kitagawa and they said to look for a server drive error on the okuma. I'm not sure what this means though.

[deadlykitten]

I did this

how ? how do you know where the axis is, if it displays overflow ?

how do you know that normal value is 0.6415 ?

with what value did you modified the machine offset ? if that value is < travel limit, and B axis is near 0, i doubt that overflow will dissapear

if you wis, pls explain from where you get all those numbers, so to have a clue what is going on




try this :
... measure the real tilt angle ( let's say that it is 5* )
... machine zero offset : input CALL + 5*; if overflow dissaperas, imediatly check end limits
write down all those values before and after your interventions / kindly

[O-MX45VAE]

My post processor outputs g90 x0y0a0b0 for line 1 on all of my .min files. So, I haven't moved b since before the issue and it is always set to 0.

I can measure, but 99.9% sure I'll be within margin of error with the measuring tools I have to determine if it is parallel to x.

[O-MX45VAE]

try this :
... measure the real tilt angle ( let's say that it is 5* )
... machine zero offset : input CALL + 5*; if overflow dissaperas, imediatly check end limits
write down all those values before and after your interventions / kindly

When I say "normal" values, I mean that is what the machine was calibrated to during setup.

I've experimented with a large range (from 20 to -20, and inbetween) of machines zero offsets, none allow it to fix the error. I'm guessing this is because the encoder is saying it is its waaay out of range, because the encoder went bad.

[deadlykitten]

I set the part zero offset for B using Calc, and normal value is 0.6415..it's calculating to -14.5812

if i get this right, this modification did not afect machine zero offset, but program zero ....

that value 0.6415, is the value since machine was calibrated ? and it is the value for program zero, or for machine zero ?

I've experimented with a large range (from 20 to -20, and inbetween)

if tilt angle is pretty close to 0, and normal travel limits are -35 + 110, i would try to modify the machine zero with a value much greater ... do you have the original machine zero value, inside the management data card ? maybe guys from kitagawa have a duplicate document, if you give them the serial number for your aixs ...

i believed that you tried to modify machine zero with (0.6415+14.5812), and nothing happened .... can you compare the value of machine zero with the values of travel limits ( machine value ) ?

[deadlykitten]

if your machine zero got modified with cca 15*, and one of those travel limits got modified with 20*, then you will encounter the overflow error, because this sum is equal to max travel = 35

it would be good to have a record of those parameters, so to check them, and restore ... this would be an easy fix

at least check if machine zero offset value is between machine travel limits value; if this condition is checked, then i am out of ideas / kindly

[deadlykitten]

hello again

1) i checked on my mills parameters, and there is the no "machine value for travels", but only "parameter value for travels"

on a lathe, this is different ...

however, at only 15* deviations, maybe you should get a diff alarm or something else, not an overflow

i would modify machine zero offset with +10 +10 +10, +100 +100, +1000, +10000, a big value, etc, a few times

if nothing happens, i would restore original value, and modify it with -10 , -100, -100000000 ... etc ... if somehow i switch from -overflow to +overflow, then maybe there is a chance

2) there may be a thing, because changing the machine zero with 360 720 1080 should all mean same real position; however, it may be possible that also travel limits should be shifted, but seems that those values can not be checked; even so, it is possible to check if they are updated, by moving the axis in manual

on a lathe, i know that for some axis, changing the encoder zero offset will also update some travel limits, in order to keep the soft limits where they are

3) on some models, inside the cabinet, is an over travel limit switch, that, once activated, allows an overtraveled axis to be manually moved back; even if your axis is in a nice position, an overflow may mean an error much greater then an overtravel

i am sorry, this is all i can do for now / kindly