Topic: DMD0082

UNTIL - Repeat Until Condition is Non-Zero

The Repeat Until Condition is Non-Zero (UNTIL) instruction ends a Repeat/Until loop in which a series of ladder logic instructions will be executed as long as the value in the ending Condition location is Non-Zero. Repeat/Until loops can be nested, and there is no practical limit to how deep the nesting can go.

Note: All of the looping instructions are 'power-rail' instructions. Even though the instructions are displayed in the left-most column of the ladder diagram (the power rail), they are created in the right-most column of the ladder logic diagram (the output column). Creating these instructions in Do-more Designer is a bit counter-intuitive because the first step is to position the edit cursor in the output column of the ladder logic diagram (the far right) instead of positioning it against the power rail (the far left).

Parameters:

Note: Use the F9 key (Element Browser) or Down-Arrow key (Auto-Complete) at any time to see a complete list of the memory locations that are valid in the current field of the instruction.

Ending Condition - designates a location that contains the value used to terminate the Repeat/Until loop. This value can be any constant value, any readable bit location, or any readable numeric location.

Status Display:

The UNTIL instruction will show the current .TimeSlice value of the Program or Task when status is ON.

The blue triangle in the upper left corner indicates this is a Yielding instruction.

See Also:

• BREAK - Exit Loop

• CONTINUE - Skip to Loop End
  
   

• FOR - Index Loop

• NEXT - Index By Step
  
   

• REPEAT - Loop Until Condition is Non-Zero

• UNTIL - Repeat Until Condition is Non-Zero
  
   

• WEND - While End

• WHILE - Loop While Condition is Non-Zero

Rung Example: