ElmoMC SimplIQ Software Manual - Manual (Page 192)

SimplIQ Software Manual Sensors, I/O and Events
MAN-SIMSW (Ver. 1.4)
12-7
ƒ In jog motions, the position command is jumped according to the position feedback,
so that the motion is unaffected by the position counter update.
ƒ If the software position reference generator stops or has already stopped, the
software position command is corrected according to the position feedback. The
motion is unaffected by the position counter update.
ƒ In PVT or PT motions, an on-the-fly position counter update may lead to an
immediate high position error, and the motor may abort with an excessive position
tracking error exception.
With UM=5, if the auxiliary encoder counter is modified, and the following is true:
ƒ
The motor tracks the auxiliary encoder with no ECAM table (RM=1, FR[3] is nonzero
and EM[1]=0)
ƒ The software position generator is idle, jogging or running PTP
the software position reference will be modified so that the motion is not affected. In PTP
mode, the PA parameter will change automatically to reflect the modification.
Example:
A PTP motion starts with PA=PX=0. After setting PA=1000;BG;, a motion 1000 counts
long is expected. If, at PX=500, the position has been reset to zero through homing, there
should be 1000 counts remaining immediately after the homing. The total length of the
motion becomes 1500.
12.5.4 Example 1: Homing with Home Switch and Index
The following homing algorithm may be used for the very common switch arrangement
in Figure
12-1.
ƒ Start the motor.
ƒ Jog back until RLS.
ƒ Jog at forward speed until home.
ƒ Look for the next index and set the position there to 0.
Figure 12-1: Sample Switch Locations
The position setting is taken by the index, because in many applications, the index is
much more accurate than the Home switch, which is needed for resolving index
ambiguity (many index pulses may occur along the path of travel).
In normal operation, the FLS and RLS serve as emergency indicators, and the motor is
not expected to reach them. RLS is visited during the homing process, in order to know
in which direction to look for the Home switch.