ElmoMC SimplIQ Digital Servo Drives-Bell Command Reference - Manual (Page 128)

PA - Absolute Position
Purpose:
Specifies that the next software position command will be a PTP (point-to-point) and
defines the target position for the next PTP motion. The position reference to the drive is
composed of an “internal” software command and an external command, calculated from
the analog inputs and the auxiliary feedback input.
In PTP motion, the drive calculates the software position reference so that a desired
target position will be reached as fast as possible, subject to the speed (SP) and the
acceleration limits (AC, DC, SD) (with possible smoothing: SF). A PTP command can be
given at any time, at any speed, regardless of the present executing motion. The drive
calculates the acceleration, speed and minimum time path to the target position, starting
from the present position and speed.
A PTP motion, like any other software motion, is initiated by a BG command. For
example, a PA=1000 command specifies that the next BG command will activate a PTP
motion, overriding any previous motion specification, and that the target position will be
1000. The new PA value causes PR to become 0. In order to make sequential PTP
movements of the same size, use the PR command. Subsequent PR settings may cause the
PA value to be changed.
Notes:
The PA value must be within the modulo range: (XM[1]…XM[2] - 1) for UM=3, 5
or (YM[1]…YM[2] - 1) for UM4, and restricted by the VL[3] and VH[3] settings.
Modulo calculation is always active; therefore, PTP motions are planned using
the shortest way. For example, if XM[1]=-500, XM[2]=500, UM=5, the present
position command is 490 and the next PA is set to -490, the PTP motion will be
planned in the positive direction, and the resulting motion length will be 20
counts.
A PTP motion will continue until completion even if the position counter value
has been reset on-the-fly (refer to the HM[N] / HY[N] 4 commands). However,
the position target does not change so that in the case of PA=n, the BG sequence
may result in a different motion length than initially programmed.
Attributes: Type: Command/Parameter, Integer
Source: Program, RS-232, CANopen
Restrictions: MO=1
Range:
Position counter range
Unit modes: UM=3, 4, 5
Activation: BG
SimplIQ: Similar
See also:
PR , BG , MO , XM[N] , YM[N] , MS , VH[N] , VL[N] , SP , AC , DC , SD , SF , HL[N] , LL[N]
4 In dual loop mode (UM=4), position feedback is PY. It can be manipulated on-the-fly by HY.
SimplIQ for Steppers Command Reference Manual Alphabetical Listing
MAN-STECR (Ver. 1.1)
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