The numbering of channels of an I/O module usually starts with 1 and counts up to the maximum number of supported channels. The software however starts numbering with a 0 for the least significant bit in a word (LSB). The Quantum I/O modules have their lowest channel mapped to the most significant bit (MSB).

Mainly discrete I/O modules can be configured to deliver their I/O data either in word format or in bit format. This can be selected during configuration by selecting either %IW (%MW) or %I (%M). If you need to access a single bit from an I/O module configured to use an I/O word, you can use the syntax %word.bit. The following table gives you the connection between I/O point number and the associated I/O address in bit and word addressing.