Siemens SIMATIC ET 200pro Operating Instructions Manual page 148

Isochronous mode
Process data, transmission cycle via PROFINET IO and user program are synchronized to
achieve maximum deterministic behavior. The input and output data of distributed I/O
modules in the system is simultaneously acquired and simultaneously output.
Isochronous real-time communication
Synchronized transmission method for cyclic exchange of IRT IO data between PROFINET
devices.
A reserved bandwidth within the send clock is available for IRT IO data. The reserved
bandwidth guarantees that the IRT IO data can be transmitted in reserved, time-
synchronized intervals and not be influenced by high network load arising from other
communication (e.g. TCP/IP communication or additional real-time communication).
Load current supply
Supply of the module's input and output electric circuits.
MAC address
Every PROFINET device is assigned a worldwide unique device identification before it
leaves the factory. This 6-byte long device identification is the MAC address.
The MAC address is divided into:
● 3-byte manufacturer identification
● 3-byte device identification (consecutive number)
The MAC address is generally shown on the front of the device.
Example: 08-00-06-6B-80-C0
Media redundancy
Function for ensuring the network and system availability. Redundant transmission paths
(ring topology) ensure that an alternative communication path is made available if one
transmission path fails.
NTP
The Network Time Protocol (NTP) is a standard for synchronizing clocks in automation
systems via Industrial Ethernet. NTP uses the UDP connectionless network protocol.
CPU 1516pro-2 PN (6ES7516-2PN00-0AB0)
Operating Instructions, 11/2019, A5E35873416-AC
Glossary
147