Allen Bradley Binary Bit (B3)

HI EXPERTS
WHAT IS THE PURPOSE OF TOGGLE BIT IN RELATION TO INTERNAL BIT , WHEN YOU TOGGLE APPROPRIATE BIT DOES IT MEAN TO FORCE ON OR OFF THAT BIT

THANKS EXPERT

When you say 'toggle bit' I assume you mean the RSLogix toggle bit function in the drop-down menu you see when you right-click a bit. This function will change the state of the bit to its opposite state when the function is selected. It will only write the bit state to the plc once when the function is selected. It is not a force. If the bit is used in an output instruction somewhere in the plc logic, the rung containing the output will determine the state of the bit when the plc scan reaches it.
This function is useful for setting or resetting latch/unlatch bits or for setting or resetting logical latches. But it is not a force. The other possible use is to put a conditional bit in a rung but do not use the bit as an output anywhere. You can then use the toggle bit function to change the state of that bit. It will also change the state of bits written to from HMIs that do direct bit access as opposed to I/O mapping.

I hope this helps.
Keith

..and also

remember, even though you're not technically 'forcing' I/O,
manipulating a bit in this fashion MIGHT have the same
'unexpected' results, depending on the logic.

Re: A thread a few days ago regarding 'old logic' If
old logic uses a bit, and you 'toggle' it, the old logic
could start doing things you do not expect to happen.