There are some uses of the DWL (dwell) command to avoid:
1. Do not use a zero value or negative values for an argument with DWL commands. This will cause the controller to have unusual response to the DWL. This problem was fixed in firmware revision 1.18.16 (a.k.a. operating system.)
2. When using an equation to determine a dwell time, you must make certain that it does not evaluate equal to zero, or a negative value. Again, this was corrected in firmware revision 1.18.16.
3. Do not use DWL commands in "non-motion" programs. PROG8 - PROG15 are considered non-motion program since they are assigned a lower priority and share a program time-slice. Because they share a time-slice, if you DWL or INH (inhibit) a non-motion program, you cause ALL of the non-motion programs to dwell or inhibit. This could cause undesired consequences.
Note: Using a DWL in a non-motion program has no affect on a "motion" program (PROG0 - PROG7.)