Yaskawa G5 Spindle Orientation - Manual (Page 4)

Spindle Orientation
Date: 07/01/04, Rev: 04-07 Page 4 of 14 TM.G5SW.021
How it Works
The function of this software is to provide the ability to orient the position encoder and any device connected to it to any
position within the PPR (pulses per revolution) resolution. This requires the position encoder to be directly coupled to
the device to be positioned, which is driven by the drive flashed with VSG11474X software. The position encoder must
also be connected to the drive via a PG option card.
This software has no effect on the normal drive functions and a drive flashed with it can be configured to operate as a
standard drive with a standard software flash. The software is only active when the orient input has been energized.
When that occurs the offset value is read and the drive will accelerate or decelerate to the threshold frequency. The
threshold frequency is determined by 4096 x P1-07: Stop Frequency Gain. If the output frequency of the drive is below
the threshold frequency the drive will accelerate at the rate controlled by C1-01: Accel Time 1. If the output frequency
is above the threshold frequency the drive will begin to decelerate at the rate controlled by C1-02: Decel Time 1. The
drive’s output frequency is monitored. When the output frequency is equal to the threshold frequency the PG card’s Z
pulse is monitored. When a Z pulse is detected the marker position is set and this software begins to orient the position
encoder. The output frequency is dynamically reduced as the position encoder nears the orient position. The orient
position is equal to the marker position plus any additional offset. When the position encoder is within the number of
counts set in P1-05: Position Count of the orient position the output frequency will be set to P1-04: Position Speed. The
drive will maintain this output frequency until the position encoder is within the number of counts set in P1-06: Stop
Count of the orient position where it will stop and zero servo until the orient input or the run input is de-energized. The
orient position maintained will be +/- the counts set in P1-06: Stop Count of the set orient position. This provides a
method to prevent oscillation while the position is being maintained. When this position has been acquired the orient
complete output will activate. If the run input is de-energized while the orient input remains energized the drive will
resume operation where it stopped when the run input is re-energized. The orient complete output will de-activate when
the orient input is de-energized.
The drive will orient the position encoder within two revolutions after the marker position has been set. Revolutions
may be added when needed by incrementing the marker offset value by the quadrature pulse count of the position
encoder. The maximum offset count value is 32767. If you are using a 1024 PPR position encoder the quadrature count
will be 1024 PPR x 4 or 4096 counts per revolution. Using this position encoder, for each 4096 counts added to the
offset the drive will require an additional revolution to orient.
All orientation is done relative to the marker position. The Z pulse from the position encoder or an external-switch
device is required to identify the marker position. P1- 03: Marker Offset parameter is provided to adjust the marker
position to the required or home position. All subsequent offset positions are relative to the home position. The stop
position or orient position is equal to the marker-offset or home position plus the current offset.
To set P1- 03: Marker Offset and identify the home position it is necessary to run the drive and perform an orient by
energizing the orient input. After the drive has stopped and holding position de-energize the run and orient inputs. The
device connected to the position encoder may be rotated into the required or the desired home position. This operation
may be done by hand or by reducing the frequency reference to the drive and using the run inputs to jog the device into
position. When the device is in position the value shown at monitor U1-50: Marker Offset must be entered into P1- 03:
Marker Offset. Monitor U1-50: Marker Offset contains the number of counts past the marker position that the position
encoder has rotated. It is a rolling counter and will restart at zero after the count has exceeded P1-02: Spindle PPR x 4.
(Rolling counter range = 0 to quadrature count –1)
There are four orient control selections. Parameter P1-10: Control Select can be used to select from the following.
0 – Marker Offset – The drive will only use P1- 03: Marker Offset as the orient position when the orient input is
energized. This is the home position.
1 – Sequenced Offset – The drive will automatically increment to the next sequence offset when the orient input is
energized. Parameters P2-01: Offset 1 to P3-05: Offset 15 are used to set the sequence offset values. These
parameters provide 15-sequenced steps. Each step can contain an offset value. When the offset value read is 0 the
sequence step will reset to 0, which is the home position. A sequence-reset input is provided and will reset the step
to 0 or the home position when energized. A home position multifunction output will activate when the sequence is