GE IC695PNC001 - Page 72

4-4 PACSystems* RX3i PROFINET Controller Manual – December 2011 GFK-2571A
4
Types of PROFINET Communications
PACSystems PNC modules use two types of PROFINET communication transfers: real-time and
non-real-time. The illustration below shows real-time communications as solid lines and non-real-
time communications as dashed lines.
RX3i Main Rack with PROFINET Controller
Non-real-time data:
parameters, configuration, etc
Real-time data:
Inputs, Outputs,
Alarms
PROFINET
IO-Device
PROFINET
IO-Device
 Real-Time (RT) communication: PROFINET real-time communication is used for time-sensitive
data. A PROFINET IO-Controller and PROFINET IO-Device use two types of real-time
communications to exchange data: cyclic communication and acyclic communication:
 Real-time Cyclic communication is used to periodically transfer the application’s input and
output data. Cyclic communication occurs each PROFINET IO production cycle.
 Real-time Acyclic communication is used to transfer non-periodic data such as alarms.
Acyclic communication occurs only when needed.
 Non-Real-Time (NRT) communication: PROFINET non-real-time communication is used for
less time-sensitive data such as configuration, parameterization, diagnostics, and identification
data.