One shot (ONS) symbol
Also called ONS, One shot, OSR
The Allen-Bradley one shot: an instruction placed on the rung that passes power for one scan when the rung before it goes true. It uses a storage bit to remember the last state.
IEC 61131-3What the one shot (ONS) symbol means
The Allen-Bradley one shot: an instruction placed on the rung that passes power for one scan when the rung before it goes true. It uses a storage bit to remember the last state.
How it is drawn
Where you see it
Edge detection in Rockwell programs, the equivalent of a P contact or an R_TRIG block.
Related symbols
Frequently asked questions
What does the one shot (ONS) symbol look like?
A small box marked ONS on the rung.
Where is a one shot (ONS) used?
Edge detection in Rockwell programs, the equivalent of a P contact or an R_TRIG block.
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