Yaskawa E7 Drive Technical Manual - Manual (Page 25)

Date: 02/25/2010, Rev: 10-02 Page 25 of 34 TM.F7SW.064
5.4 Alignment Function
5.4.1 Alignment Enable
In order for the alignment function to be enabled, both the master and the follower trigger multi-function
digital input functions need to be programmed into the H1-0X parameters, and parameter P4-01 needs to
be set to a non-zero value.
The alignment function will NOT operate under the following conditions:
• Drive is faulted
• Drive is not running
• Follower is ramping between forward & reverse run commands
• Electronic Lineshaft is disabled via a multi-function input (H1-0X = 80)
• Electronic Lineshaft is disabled via parameter (P1-01 < 4)
• Drive is in “Local” mode
• A “Jog” is being commanded of the follower drive
• Drive is ramping to speed due to a gear ratio change or Lineshaft being re-enabled
• Position error is being cleared via a multi-function input (H1-0X = 87)
5.4.2 Alignment Select
The alignment select parameter (P4-01) enables / disables the alignment feature. When P4-01 = 0, the
drive will not do an alignment and the two digital outputs associated with alignment (H2-0X = 41 & H2-0X
= 42) will remain de-energized.
• P4-01 = 0 – Disabled . The drive will NOT perform an alignment.
• P4-01 = 1 – Manual Alignment . The drive must see the rising edge of the align command (H1-
0X = 8B) in order to start the alignment process. The drive will not attempt another alignment until
there is another rising edge on the align command.
• P4-01 = 2 – Auto Align at Start . The drive will attempt to complete the alignment process once
as soon as the run command is applied. The drive will then respond to the align command as
stated above (P4-01 = 1).
• P4-01 = 3 – Continuous Alignment . The drive will attempt to complete the alignment process as
soon as the run command is applied. Each time two valid trigger inputs are received, the drive
will automatically re-start the alignment process. Trigger pulses will be ignored if the drive has not
completed the previous alignment attempt.
5.4.3 Alignment Process
The alignment function can be used to align the follower to the master using fixed trigger positions. This
process does not control the master drive. All correction is made by the follower drive. The amount of the
correction is controlled by the quadrature counts that are accumulated from the time when the first
(leading) trigger starts the process and continues until the second (trailing) trigger stops it. The speed of
the correction is controlled by parameter P4-02. The correction will be made as soon as the trailing
trigger input becomes active. The rate at which the drive accelerates or decelerates during the alignment
procedure is fixed. For a 1024 PPR encoder, the ramp rate will be about 20 Hz/ 1 sec. The alignment
process is intended to be performed at low speed, but will function as long as the triggers provide at least
a 15 millisecond signal so that the follower drive can see the trigger inputs.
Maximum alignment speed: If an alignment is in process and the follower needs to run faster to “catch
up” to the master, it will only be allowed to compensate at a rate of up to 95% of the follower’s maximum
frequency setting. If the follower is already running at or above the 95% speed level, the alignment
function will not complete.
Minimum alignment speed: If an alignment is in process, and the follower needs to slow down in order for
the master to “catch up”, the follower drive could run in reverse. If reverse on the follower is disabled (b1-
04 = 1), the follower drive will only be allowed to run at a minimum of zero speed (no reverse).