[Frank_W]

Hi

We have an old Dah Lih MCV 1000 to upgrade from 1985ish vintage Fanuc 11M to Mach3 Kanalog Kflop. Early in the planning stage - or what might be better called the dumb question phase.

I am not by any means a CNC technician but have a little experience with such technologies... would maybe be more comfortable if it involved pegboards, uniselectors, a large number of post office relays and perhaps thyratrons or magamps in the drivers.

This machine has 4 axis - servo motors are DC yellow caps with H003 Drivers - the spindle motor is a model 6 fanuc AC motor and including the 25 st tool changer system it has a lot of limit switches

It is a very stable system and the servo and spindle drivers/motors work very well so not on the upgrade or replace list. The servomotors do not have tachos - feedback for the velocity loop seems to be from the encoders via the controller - which leads to the first planning uncertainty/knowledge limit.

I have read here various discussions regarding the merits of torque versus velocity control and sort of grasp the torque control single loop advantage - but I am always careful changing what works well so the question is to someone with experience doing such things.

Can an H003 driver run without any change - just the control voltage input with the velocity loop simply left open - and Kflop tuning the whole loop? Seems too easy... (except perhaps for actually tuning the loop)

Or am I misunderstanding something here?

We need to add a "connection" board to Kanalog to deal with all the limit switches - the wanted push buttons - the MPG and the tool changer - so extra analog output needed for the spindle if we use two per axis servo perhaps not a problem.

The spindle is interesting - 2 speed gearbox thing. Only spindle position/speed feedback found is a single proximity sensor sensing a bar screwed to one side of the spindle - guess this is an orientation sensor. Please tell me orientation and the spindle speed feedback all happen on the spindle controller and all Kflop has to do is issue appropriate commands/control voltage.

The questions about where the 80 column card reader plugs in will come up after I have powered.up the Dynomotion unit. (Joking... I have a C++ guy helping soon so maybe he can tell me!)

'Tis the first of several upgrades if we get it right - next is a Maho MH800 in pristine condition except for a non functioning Philips 432 controller...

Cheers

Frank

[TomKerekes]

Hi Frank,

Sounds like quite a project. I'm not familiar with the Fanuc DC Yellow Cap Motors or H003 Drives. But I'm confused by your description. If the original configuration had no Tach and the original controller closed the entire loop around the encoder, then wouldn't it also have been operating in Torque mode? So what would you be changing? And why would the driver have a Tach input that you would need to leave open?

Regards

[Al_The_Man]

Fanuc Yellow cap are fairly standard Brushed DC motors, it is unusual not to see tach F.B. to the drive, which are 3 phase SCR type controllers.
Al.

[Frank_W]

Hi Folks,

Thanks for the response

I was guessing the controller is not simply closing a single loop but has somewhere nothing more than a frequency/voltage converter which is merely substituting for the tach in the velocity loop. Assuming this because the driver has an active velocity feedback input.

Guess the easiest way to find out is to measure what is happening... I'll let you know when I figure it out.

Cheers

Frank

[Frank_W]

Acquired a Fanuc 10 11 12 system maintenance manual. There is a F/V converter output used as a velocity feedback signal (when a pulse coder is used)... so while it doesn't have tachos it does have a velocity feedback to the drive.

We'll measure some gains and leave both options for control loops...

Cheers