Basic Bit Instructions
These are the most common instructions in PLC programs.
You would think that would make them the most understood instructions but quite the opposite, these are the most misunderstood instructions in ladder logic. If you use Tim Wilborne’s explanation, you’ll be on your way to understanding ladder logic in under an hour.
Go look for a 1. Some people call this an XIC, an Examine if Closed, an Examine On, a Direct Contact, or a Normally Open Contact.
Go look for a 0. Some people call this an XIO, an Examine if Open, an Examine Off, a Reverse Contact, or a Normally Closed Contact.