ElmoMC SimplIQ Digital Servo Drives-Bell Command Reference - Manual (Page 192)

XM[N] - X Modulo
Purpose:
Specifies the counting range for the main feedback, which is [XM[1]…XM[2]-1].
The position of the main feedback is always counted cyclically. This means that after
the position is counted to its maximum value, the next position count will reset the
position counter back to its minimum value. The speed reading is not affected by the
position jump. For example: If XM[1]=-5 and XM[2]=5, the main position is counted in
a cycle length of 10. The main position will always be in the range [-5…4]. If the main
feedback rotates in the positive direction, the main position count will proceed from 0,
1, 2, 3, 4 to -5, -4, -3, -2, -1, 0, 1 . . . and so on.
If XM[N] is non-zero with UM=5, the controlled motor position will count cyclically.
All motion trajectories will go the short way. For example: If XM[1]=-512, XM[2]=512,
the initial position is PX=-500 and the target absolute position is PA=500, the PTP
trajectory will travel through -500…-512, 511…500 to a total distance of 23 counts.
The cycle length must be positive (XM[2] > XM[1]) and (XM[2] - XM[1]) must be an
even number. XM[N] values violating the above conditions will be accepted, but not
activated. Until XM[N] can be activated, the motor cannot be started and the
parameters cannot be saved in the flash memory (the SV command will not work).
Notes:
If XM[1] or XM[2] is set so that XM[2] > XM[1] but PX is out of the range
[XM[1]…XM[2]], PX will be set to range by taking modulo:
PX = (PX - XM[1]) mod (XM[2] - XM[1]) + XM[1]
If a homing process requests a PX value setting out of the range [XM[1]…XM[2]],
the request will be ignored and PX will not change.
If the XM[N] value is selected low and the main speed is too high, more than one
full revolution of the main counter may elapse within a single sampling time.
This will cause the main position counter to behave unpredictably.
XM[N] cannot be modified while the homing sequence is active (HM[1] > 0).
For open loop stepping of rotary motors, XM[2]-XM[1] must be an integer
multiple of PN[4], otherwise stepping angle jumps shall appear on position
modulo transitions.
SimplIQ for Steppers Command Reference Manual Alphabetical Listing
MAN-STECR (Ver. 1.1)
184