Yaskawa MP940-MW+ - Manual (Page 13)

TECHNICAL NOTE
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04 Home
The home subroutines takes advantage of the Home block (4) which has built in
functionality for homing to and through a deceleration switch then to the C (zero) pulse of the
encoder. After that is complete an offset move is completed, then the set position block (6) re-
defines the position to 0.0 (this could be a user variable). In this program that same block also
sets the external position to 0.0 (again that could be a user variable also). The reason for the
time delay block (7) is the position redefinition takes place in the Low Scan (this block actually is
not necessary as the system ladder version 283 has been update to wait until the position has
been updated before moving to the next block). The delay ensures that the block has had
sufficient time to finish before allowing further execution. Blocks 3 and 8 take care of activation
and deactivation of some internal user variables [Homed] and [Homing]. Block sets a user error
variable [ErrorHoming] which is detected in the supervisor. Lastly, input block (10) ensures that
the user has deactivating the homing request input (Local_Input4). If this block was not in place
and the user left the home request on, the machine would home over and over.
05 Move
Move subroutine is simple relative move, which incorporates a programmable limit switch
(PLS) block and a couple of timers. This subroutine differs slightly from the others in that there is
not an event that locks it in the subroutine. Once the move is complete and the timers have