Rockwell Automation 1747-L40 SLC 500 Fixed Hardware Style - Manual (Page 64)

5
Chapter
5–1
Wiring Your Control System
This chapter describes how to wire your I/O modules. It covers the
following:
•
defining sinking and sourcing
•
determining approximate transient duration
•
preparing your wiring layout
•
features of an I/O module
•
recommendations for wiring I/O devices
•
wiring your I/O modules
•
using Removable Terminal Blocks (RTBs)
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 the 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 from sourcing field devices.
Defining Sinking and
Sourcing