XIO — Examine If Open
XIO (Examine If Open) in rungs.dev passes power along the rung when the referenced bit is 0 — a normally-closed contact.
dataBit
Passes power along the rung when the referenced bit is 0. Equivalent to a normally-closed contact.
Operands
| Name | Type |
|---|---|
dataBit | BOOL |
How It Works
If dataBit is 0, power passes through. If 1, power is blocked.
Example
0
Fault
Ready
Ready is energized while Fault is 0.
Practice
Try XIO in the Lamp Inverted exercise — light a lamp while a button is released.
Looking for NOT?
There is no NOT contact in Ladder Logic. For inverting a bit on a rung, XIO is the NOT — it passes power when the bit is off. (Do not confuse it with the Move/Logical NOT block, which complements a whole DINT word rather than a single bit.)
Common Mistakes
- Expecting a
NOTor!symbol on a contact — useXIOinstead.
Related
- XIC — the non-inverted counterpart
- Bit instructions overview
- Logical instructions — the
NOTblock, for inverting a wholeDINTword
XIC — Examine If Closed
XIC (Examine If Closed) passes power along a ladder rung when the referenced bit is 1 — a normally-open contact in the rungs.dev ladder simulator.
OTE — Output Energize
OTE in rungs.dev is the standard output coil — sets a BOOL bit to 1 while the rung is true and back to 0 when the rung goes false. The default ladder output.