Rockwell Automation 1761-HHP-B30 MicroLogix 1000 with Hand-Held Programmer (HHP) - Manual (Page 268)

Chapter 14
Using High-Speed Counter Instructions
14–18
If a fault occurs due to the HSL instruction, the HSL parameters are not
loaded to the high-speed counter hardware. You can use more than one HSL
instruction in your program. The HSL instructions can have different image
locations for the additional parameters.
!
ATTENTION: Do not change a preset value and an output
mask/source with the same HSL instruction as the accumulator is
approaching the old preset value.
If the high-speed counter is enabled and the HSL instruction is
evaluated true, the high-speed counter parameters in the HSL
instruction are applied immediately without stopping the
operation of the high-speed counter. If the same HSL instruction
is being used to change the high-speed counter controlled
mask/source and the preset, the mask/source is changed first and
the preset second. (The preset is changed within 40
µ s after the
mask/source.) If the original preset is reached after the new
mask/source is applied but before the new preset is applied, the
new outputs are applied immediately.