lathe retrofit

Hello all,i have a korean cnc lathe with fanuc ot-c controller and fanuc red cap servo motors and fanuc red cap spindle motors.the machine is in good condition mechanically,but i am getting lot of probs with controller and the drives part though both axis servo motors and spindle motor is in good condition.i want to retrofit it by myself using EMC2.as the motors are in good condition i want to use the same fanuc motors for the retrofit.so my question is,is this retrofit possible with the same fanuc motors?if yes which drives i can use for spindle motor and servo motors and which i/o cards from mesa i can use?plz can someone help me on this.

thanks in advance.

possibly...
Do you have the motor and encoder specifications? (part numbers will do)
If the drives are OK they may be reusable also (part numbers would help here also)

andypugh wrote:

jlbs00 wrote:

so my question is,is this retrofit possible with the same fanuc motors?if yes which drives i can use for spindle motor and servo motors

You should be able to use the motors, and if possible keep the same drives, it will just make things easier.

However, it is possible to run Fanuc motors with generic AMC drives and the parallel port: www.cnczone.com/forums/vertical_mill_lat...-18.html#post1020710

Fanuc "Velocity Control Units" ie. servo amps, need tachometer feedback. BUT, these machines
do not have tachometers. What they do is make a synthetic tach signal from the encoder.
This is part of the CNC control, and basically impossible to separate out. The Fanuc
amps can be switched over to torque mode control, but this would require some significant
retuning effort on all those trim pots. So, that's one problem.

A second problem is Fanuc used to be very public with documentation, back around
1984 or so, you got complete schematics of all the boards. Later, they got very
secretive, and you couldn't get anything beyond drawings of the cables.
I'm not sure what vintage an OT-C is, but since you say red cap motors, it has
to be later than '84.

I (Pico Systems) do have adapters that convert the proprietary Fanuc encoder signals
to industry compatible, and have customers using my PWM controller and
brushless amps with Fanuc red cap motors.

Jon

andypugh wrote:

jmelson wrote:

I (Pico Systems) do have adapters that convert the proprietary Fanuc encoder signals
to industry compatible, and have customers using my PWM controller and
brushless amps with Fanuc red cap motors.

I should perhaps have been more clear that running the Fanuc motors directly from a parallel port isn't a particularly good idea, but has been done as a proof of concept.

Jon: Which variant of the encoders do you support? Is it just the gray-code + quadrature type, or can you interface to the serial encoders?

The first generation of red cap motors had standard differential quadrature plus index encoders
with a proprietary commutation system, as you refer to above. I have a converter that passes
through the quadrature and index, and turns their proprietary commutation into industry
compatible "Hall" format signals. These are 1500, 2000, 2500, 3000 and 10,000 line
encoders. These are usually marked as "pulse coders".

The later series have a serial format, and I have a converter that supports some of those
models. These usually have 32K, 64K, 128K and 1 million counts/rev. I have tested with the
64K and 128K models, mostly. My converters for these generate traditional Hall commutation
signals, and also convert the last reported position to quadrature. It reads the position
10,000 times a second. After each position reading, it outputs a burst of quadrature
counts at an adjustable rate until the quadrature position equals the encoder
position value. Since this is done at the 10K/second rate, it doesn't foul up most
positioning loops. But, it makes velocity estimation from timestamping of the
last received count somewhat rough.

Jon

hi all,

sorry for the late reply as all the numbers on the drives and motors were omitted .so I had to look for a similar machine or machine with similar spindle and servo configs.i somehow found a machine which is not exactly my type of cnc but very close to it.

servo drive type-a06b-6058-h224(S series digital servo amp).
this servo drive supports 10S motors(Red Cap) with motor type a06b-0315-bxxx(ac servo motors).
encoders for x and z -type- A860-0304-T111 2000P (incremental black cap encoders).

SPINDLE DRIVE TYPE- A06B-6055-HXXX(AC DIGITAL SPINDLE DRIVE).
thx in advance

jlbs00 wrote:

hi all,

sorry for the late reply as all the numbers on the drives and motors were omitted .so I had to look for a similar machine or machine with similar spindle and servo configs.i somehow found a machine which is not exactly my type of cnc but very close to it.

servo drive type-a06b-6058-h224(S series digital servo amp).
this servo drive supports 10S motors(Red Cap) with motor type a06b-0315-bxxx(ac servo motors).
encoders for x and z -type- A860-0304-T111 2000P (incremental black cap encoders).

SPINDLE DRIVE TYPE- A06B-6055-HXXX(AC DIGITAL SPINDLE DRIVE).
thx in advance

OK, these servo amps generally require tach feedback, but the motors do not have
tachometers. So, they depend on the CNC control to provide the synthetic
tach signal, so the amps can run in velocity mode. The older amps had some
jumpers that could be changed to put the amp in torque mode, I don't
know how you do that on the digital servo amps. Also, the older amps
required 6 PWM signals for EACH motor to set the on-time for each
transistor. I don't know if that complexity has been moved inside the drive
in the later models. There are some outfits that have put some Fanuc
manuals online, you might want to do some web searches.

Do you have real 3-phase power at your location? If not, it may make
more sense to replace the Fanuc drives with something that can run
off single-phase power.

Jon

The A06B-6058 series are digital drives (The A06B-6057 seres and earlier servo (not spindle) drives are analog)

We are working on an interface for the digital servo drives but I cannot promise a completion date.
These drives have 6 (older) or 3 (newer) PWM signals for the power transistors and
2 analog current feedback signals, Thats is they are basically only power stages with fault and current sense.
When the drive is not ready, some of the PWM signals change roles (and reverse direction) and provide
4 bits of drive fault information back to the controller.

The A06B-6055 spindle interface is more problematic as it uses a proprietary serial protocol for spindle control