Time Synchronization Between The Control And Converter; Overview - Siemens SINAMICS S120 Function Manual

11.8

Time synchronization between the control and converter

11.8.1

Overview

In the factory setting, SINAMICS S120 drives use an operating hours counter. Based on the
operating hours, SINAMICS S120 saves alarms and warnings that occur. Using this method,
it is not possible to have a comparable timestamp between various converters.
In order to obtain a comparable timestamp between several converters, you must change
over the operating hours counting to time in the UTC format and synchronize with the time
master (control system).
This means that the events of all bus nodes, which are synchronized with the control system
time, can be referenced with one another.
Benefits: Improved diagnostic options by having a comparable time stamp of the bus nodes
involved.
Converters provide the following options to synchronize the time:
Synchronization type
Basic synchronization
Synchronization using ping compensation for non-isochronous communication
Synchronization using ping compensation for isochronous communication
Synchronization with the Network Time Protocol via a PROFINET connection
Principle of operation of time synchronization
Basic synchronization
The control system transfers the time to the converter at time intervals that you specify in the
control system. Transfer is realized acyclically in the UTC format. The converter accepts this
time as soon as transfer has been completed without correcting the transfer duration. The
converter logs alarms and warnings based on this time.
Time synchronization with ping compensation
At intervals that you specify in the control system, the control system sends a ping (a positive
signal edge) cyclically to the converter. Simultaneously, in acyclic operation, the device
sends the time in the UTC format in what is known as "snap".
As soon as the ping has been received in the drive, a timer starts which measures the time
until the snap has been completely transferred. The drive accepts the time that the snap
transfers. It then corrects it by the time that has expired between receiving the ping and the
complete transfer of the snap.
Drive functions
Function Manual, 11/2017, 6SL3097-4AB00-0BP5
11.8 Time synchronization between the control and converter
Communication
Accuracy
approx. 100ms
approx. 10 ms
approx. 1 ms
approx. 10 ms
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