Issue
There are often customer requirements to send safety related data over communications links. At the same time, the requirement automatically arises for the transference of safe and non-safe data via a collective standard network. A safe network will allow the Safety controller to communicate with each other and provides a robust and safe means of sending safety related data using the communications medium that best suits the applications and budget.
Resolution
With M580 Safety CPU firmware 3.20 or later, the safe time synchronization is based on an internal "monotonic" time clock. The safe communication DOES NOT need NTP time synchronization as the CPU is sharing its safe time with all its local and remote I/Os. The remote I/O drop uses BM•CRA31210 module and must have a firmware 2.60 or later to work.
A monotonic clock is a time source that always moves forward and will not be impacted by variations leading to jumps in time (due to NTP or Daylight Savings Time updates). Monotonic uses Thomas Habets's cross platform "monotonic_clock" library under the hood.
Attached herewith are two documents file that guide you on how to implement Safe Peer-to-Peer communication between two M580 Safety ePAC (MASTER PAC and SLAVE PAC).
Disclaimer
The views and opinions expressed in this article are those of the author(s) and do not necessarily reflect the official policy or position of Schneider Electric.
