Fagor CNC 8055i, Installation Manual

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Installation manual
CNC 8055
CNC 8055i
CONC
EPTS
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7.9.4 Spindle in closed loop
One of the following conditions must be met in order for the spindle to operate in closed loop by
means of "spindle orientation (M19)":
• It is an analog or digital drive with feedback to the CNC (via connector) and spindle parameter
NPULSES (P13) is other than 0.
• It is a digital drive (SERCOS or CAN) with feedback to the drive and spindle parameter
DRIBUSLE (P51) is other than 0.
Also, when switching from open to closed loop, either an "M19" or an "M19 S±5.5" must be executed.
The S±5.5 code indicates the spindle position, in degrees, from the spindle reference point (marker
pulse).
When switching form open to closed loop, the CNC behaves as follows:
• If the spindle has a home switch:
In this case, it is possible to detect the right reference mark among the possible ones (having
the encoder at the motor) originated especially by different gear ratios.
In order for the drive to detect the right reference mark, the home switch detection must be
accurate. This is achieved by having the spindle turn one more revolution once the home switch
has been detected. The end portion of this last spindle revolution is carried out slowly.
Spindle home search:
The spindle must have an encoder so it can be homed.
Once the home switch has been detected, the spindle will keep turning in the same direction
and at the speed indicated by spindle parameter REFEED1 (P34). Before completing the next
350º, the spindle slows down to the speed indicated by spindle parameter REFEED2 (P35). From
then on, the home switch is detected while turning at REFEED2 speed and keeps moving until
detecting the reference mark.
Considerations:

The first movement until the home switch is detected and the entire next process is carried
out in the direction indicated by spindle parameter REFDIREC (P33).

The home search may be started when the spindle is stopped or moving (M3 or M4). If the
home search starts when the spindle is stopped or it has to change its turning direction, the
transition from the starting speed S0 to the one indicated by spindle parameter REFEED1
will be made with a linear acceleration ramp.

If the home search starts when it is stopped and the home switch is pressed, it will also turn
one more revolution.

This type of spindle home search may be carried out with a SERCOS, analog or CAN drive.
In order for it to work on CAN or analog spindles when there are several reference marks
per revolution due to different gear ratios, the reference mark must be managed with the
DECELS signal ignoring the actual (real) reference mark signal.
For greater accuracy, if the average cycle of the PLC exceeds 8 ms, we recommend to
manage the DECELS input at the PLC with a periodic cycle equal to or shorter than 8 ms.
It is also recommended to manage the DECELS input from a local input.
REFEED1
350º
REFEED2
I0
DECELS