Installation manual
CNC 8035
CONCEPTS
Spindle
5.
(SOFT M: V15.3X)
(S
OFT T: V16.3X)
·231·
When managing the DECELS input from a CAN remote input, use the commands IREMRD,
OREMWR and MWR inside the periodic cycle to obtain proper synchronism.
PE **
IREMRD
NOT I200= DECELS
OREMWR
MWR
END
The delay of the DECELS signal detector can cause a low home search feedrate
"REFEED1". In order for this not to affect successive positioning movements that are not
related with home search, we recommend to use a positioning feedrate higher than
"REFEED1" through the "M19FEED" variable and its associated PLC mark "PLCFM19".
• If the spindle does not have a home switch:
If the spindle does not have a home switch, it searches the encoder marker pulse at the turning
speed set by s.m.p. REFEED2 (P35). S.m.p. REFDIREC (P33) sets the spindle homing
direction.
Then, it positions the spindle at the programmed S±5.5 point. S.m.p. REFVALUE (P36) sets the
position value assigned to the reference point of the spindle (home or marker pulse).
Calculating spindle resolution
The CNC assumes that one encoder revolution represents 360º. Therefore, the feedback (counting)
resolution depends on the number of lines of the spindle encoder.
Resolution = 360° / (4 x number of pulses per revolution)
Hence, to obtain a resolution of 0.001º, a 90,000 line encoder is required and a 180,000 line encoder
to obtain a resolution of 0.0005º.
s.m.p. NPULSES (P13) must indicate the number of square pulses supplied by the spindle encoder.
In order to be able to use feedback alarm on the spindle encoder, "FBACKAL" (P15), the pulses
provided by the encoder must be differential (double ended) squarewave "DIFFBACK (P14) = YES".
Gain setting
The various types of gains must be adjusted in order to optimize the system's performance for the
programmed movements.
An oscilloscope is highly recommended to make this critical adjustment by monitoring the tacho
signals. The illustration below shows the optimum shape for this signal (on the left) and the
instabilities to be avoided during start-up and braking.
There are three types of gain. They are adjusted by means of machine parameters and following
the sequence indicated next.
Proportional gain
It defines the velocity command corresponding to a feedrate resulting in 1º of following error.
It is defined with s.m.p. PROGAIN (P23).
Feed-forward gain
It sets the percentage of velocity command due to the programmed feedrate.
To Next Page
Loading...
