Wiring Your I/O Modules
This chapter describes how to wire you I/O modules. It covers the
defining sinking and sourcing
preparing your wiring layout
features of an I/O module
recommendations for wiring I/O devices
wiring you I/O modules
using removable terminal blocks
Defining Sinking and
Sinking and sourcing are terms used to describe a current signal flow
relationship between field input and output devices in a control system and
their power supply
Field devices connected to die positive side (+V) of the field power
supply are sourcing field devices.
Field devices connected to the negative side (DC Common) of the field
power supply are called sinking field devices.
To maintain electrical compatibility between field devices and the
programmable controller system, this definition is extended to the
input/output circuits on the discrete I/O modules.
Sourcing I/O circuits supply (source) current to sinking field devices.
Sinking I/O circuits receive (sink) current form sourcing field devices.