This video gives basic information on Using the CNTDN ""Down counter" instruction in the Do-more designer software. It presents information that is commonly missed by users. This WILL NOT be a complete tutorial for the instruction but rather a supplement to the help file and customer experience.
This is a multi-scan instruction, because it takes multiple scans to complete, it cannot be used in either Subroutines or Interrupt Service Routines. It can used in Programs and under special circumstances can it be used in Stages inside of a Program or in Tasks. See the help topic “Instruction Set Chart” for more information. . This instruction has two power rail connections. One for the input counts and one for the reset. Notice that the Down input is edge triggered and will reduce the count each time there is a transition. When the Reset rail becomes true the count becomes equal to the value of the preset. When this reset rung is turned on the accumulated count will remain the value of the preset and disregard any input counts.