User`s manual

7-40 Motion Mate™ DSM314 for Series 90™-30 PLCs User's Manual – January 2001 GFK-1742A
7
t
v
Jog
Feedhold
Applied
Feedhold
Removed
Feedhold with the DSM314
Feedhold is used to temporarily pause program execution without ending the program, often to
examine some aspect of a system. It causes all axis motion to end at the programmed
acceleration. When Feedhold is ended, program execution resumes. Interrupted motion will
resume at the programmed acceleration and velocity.
Feedhold is asserted by turning ON the
Feed Hold
%Q bit and lasts until the %Q bit is turned
OFF. The
Abort All Moves
%Q bit turning ON or an error that would normally cause a stop error
will end feedhold as well as terminate the program. During Feedhold, jogging positive and
negative is allowed, but no other motion. When Feedhold is terminated and program execution
resumes, the DSM314 remembers and will move to its previous destination.
Example 16: Feedhold
The following example illustrates a motion profile when Feedhold is applied. The linear move
accelerates to the programmed velocity at the programmed rate. Feedhold is applied at the dashed
line, so velocity decreases at the programmed acceleration to zero. Then, a Jog is performed using
the
Jog Minus %Q
bit. This is evident because the jog velocity is negative. Note that the
acceleration used during the Jog is the current
Jog Acceleration,
which is different than the
programmed acceleration. Note also, the
Feed Hold
%Q command must be applied during the
entire duration of the Jog. After the jog motion has ceased, the Feedhold is ended and the
program continues to completion.
ACCEL 1000
VELOC 2000
PMOVE12000, INCR, LINEAR
Figure 7-20. Feedhold Example