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clocking Encoder to Servo motor FAGOR servo/controler

Stirling

Hot Rolled
Joined
Dec 11, 2013
Location
Alberta canada
is my only option to send it back to manufacture or is it possible to do by myself in the shop? (manufactuture depo is thousands of kilometers away)
i belive its slipped enough to start causing intermitent problems. the servo is flagging several errors off and on. overtravel, signal oversaturation, overload, out of range...

it seems like the encoder is juuust out of alignment enough that the motor "overworks" to hold position though there is no load, causing heat build up and errors to flag when in use, or upon start up it likes to "jump" a few inches if its not hommed quickly.

the reason i think it not clocked corredt is becouse ive had the servo apart before (intigrated break problems) and attempting to reasemble it, these same symproms occured
ive managed to reasemble this once by inching it along the axisapperently got very lucky and it worked, another time i spent 2 days inching it and no luck :/

So.. any tips,tricks, software i can use to tackle this, or am i shpping it accross the whole country?
apperently new ones are not availble (its a 2005) and a new style would rewuire a controler retrofit rendering the lathe scrap at that price.
 

CarbideBob

Diamond
Joined
Jan 14, 2007
Location
Flushing/Flint, Michigan
On many servos the encoder also contains the commutation tracks.
These have to be precisely aligned to the rotor/magnets or compensated for in the servo control.
Not an easy at home task.
If this the case any decent servo motor repair shop should be able to align it for you.
Bob
 

Stirling

Hot Rolled
Joined
Dec 11, 2013
Location
Alberta canada
On many servos the encoder also contains the commutation tracks.
These have to be precisely aligned to the rotor/magnets or compensated for in the servo control.
Not an easy at home task.
If this the case any decent servo motor repair shop should be able to align it for you.
Bob

I belive this is the case, hence it seems to fight itself, making the motor very warm.
i managed to align it once, wish it would be that easy again. clearly all blind luck the once
 

Vancbiker

Diamond
Joined
Jan 5, 2014
Location
Vancouver, WA. USA
Few end users have the means to do this if the encoder does have the commutation pattern. You need a DC power supply capable of delivering about .5 the rated current of the motor and also an oscilloscope. You'll also need info from the motor manufacturer about what pin on the encoder connector to monitor with the o'scope. Energize two legs of the 3 in the motor with DC power. This will cause the motor to rotate a bit and firmly lock into a position. Then you monitor the encoder pulse while slowly twisting it back and forth watching for the rising and falling signal. Where the signal just changes state is where you lock it in.
 

atex57

Hot Rolled
Joined
Sep 6, 2006
Location
SW Wisconsin
Few end users have the means to do this if the encoder does have the commutation pattern. You need a DC power supply capable of delivering about .5 the rated current of the motor and also an oscilloscope. You'll also need info from the motor manufacturer about what pin on the encoder connector to monitor with the o'scope. Energize two legs of the 3 in the motor with DC power. This will cause the motor to rotate a bit and firmly lock into a position. Then you monitor the encoder pulse while slowly twisting it back and forth watching for the rising and falling signal. Where the signal just changes state is where you lock it in.

Which encoder pulse? A, B, Z, Comm?

A friend of mine sent out a motor and the guy did not retime the encoder and had much the same problems. Had to send it to the Mfg and paid dearly.

Ed.
 

Stirling

Hot Rolled
Joined
Dec 11, 2013
Location
Alberta canada
Few end users have the means to do this if the encoder does have the commutation pattern. You need a DC power supply capable of delivering about .5 the rated current of the motor and also an oscilloscope. You'll also need info from the motor manufacturer about what pin on the encoder connector to monitor with the o'scope. Energize two legs of the 3 in the motor with DC power. This will cause the motor to rotate a bit and firmly lock into a position. Then you monitor the encoder pulse while slowly twisting it back and forth watching for the rising and falling signal. Where the signal just changes state is where you lock it in.

im told the controler has a built in O.Scope, i wonder if i could just turn on the machine and use it to tune its alignment? need to find out how to activate it i guess
 

CarbideBob

Diamond
Joined
Jan 14, 2007
Location
Flushing/Flint, Michigan
im told the controler has a built in O.Scope, i wonder if i could just turn on the machine and use it to tune its alignment?
NO
You can buy one for 80 bucks on amazon but you need to know what you are doing and how the energize the motor to the poles.
There is always the guess and check method until it seems to be working okay...:willy_nilly:
A,B,Z are encoder counts not motor commutation. There is a way to commutate off the Z pulse using the A and B and knowing counts per rev but this is very, very rare.
DC spindle brushes also need a somewhat similar alignment on rebuild but here there is no live running feedback.
There are thousands of servo motor repair shops out there that will make your life simple.
Do you grind your own endmills, carbide inserts, drill bits from rod or solid blanks?
Bob
 

Stirling

Hot Rolled
Joined
Dec 11, 2013
Location
Alberta canada
NO
You can buy one for 80 bucks on amazon but you need to know what you are doing and how the energize the motor to the poles.
There is always the guess and check method until it seems to be working okay...:willy_nilly:
A,B,Z are encoder counts not motor commutation. There is a way to commutate off the Z pulse using the A and B and knowing counts per rev but this is very, very rare.
DC spindle brushes also need a somewhat similar alignment on rebuild but here there is no live running feedback.
There are thousands of servo motor repair shops out there that will make your life simple.
Do you grind your own endmills, carbide inserts, drill bits from rod or solid blanks?
Bob

Its great advice! I just always inqire if i can learn and do it myslf as im very northern and service calls can write off a used machine! in this case im sure it will get sent the 3000km accross canada. its acually not terribly expensive, around $1000, but 3 weeks down on my only lathe :/ just hopped it would be somthing maybe easy is all! i just dont want it to become habbit as it went there last year for the same service, why the change? no clue

need to be a diy guy up north :p
 

Vancbiker

Diamond
Joined
Jan 5, 2014
Location
Vancouver, WA. USA
Which encoder pulse? A, B, Z, Comm?

A friend of mine sent out a motor and the guy did not retime the encoder and had much the same problems. Had to send it to the Mfg and paid dearly.

Ed.

They do not use the position signals (A and B) nor one rev (Z) pulse. Most motors use a 4 bit gray code that is built into the encoder in addition to the position signals.
 

Vancbiker

Diamond
Joined
Jan 5, 2014
Location
Vancouver, WA. USA
im told the controler has a built in O.Scope, i wonder if i could just turn on the machine and use it to tune its alignment? need to find out how to activate it i guess

As Bob said, no. Controller built-in o'scope is used for servo parameter tuning. Looking for things like overshoot or hunting where tuning the parameters can correct those problems.
 








 
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