HardwareΒΆ

Two same type AC500 PLCs are required as central hardware components. Each PLC is equipped with at least two ETHERNET ports in CPU or in a communication module. The two PLCs, called PLC A and PLC B, are linked by ETHERNET to exchange and synchronize information (Sync). Connections to the AC500 peripheral field devices (I/O) are performed via ETHERNET as well.

Peripheral devices usable are CI521-MODTCP or CI522-MODTCP which communicate via the Modbus TCP protocol with the PLCs. Based on the life systems status exchanged between PLC A and PLC B over the Sync, in the event of a fault in the system the primary PLC may switch automatically to the secondary in a fast, bumpless way: Allowing the process control and status data exchange to continue unnoticed by the process. Faults will result in error messages so that repair can be initialized.

HA-Modbus TCP library supports currently up to 100 CI52x I/O clusters, depending on CPU type. Each CI52x cluster can support up to maximum of 10 S500-I/O modules on it.

  • SCADA/ PC connection is done using ETH ports of both PLCs and one or several ETHERNET switches depending on the redundancy requirements in the ETHERNET levels.
  • HA communication between PLC A and PLC B is done via two physical communications between PLC A and PLC B, using Sync (UDP) and lifecom2 (Modbus TCP or CAN).
  • Field devices (CI52x modules) will be connected via ETHERNET switch forming a redundant network (if requested). For details on network configuration see HA-Modbus TCP - System Technology.

Example

HA hardware configuration based on V3 PLC. The Sync connection is via SCADA Network, lifecom2 is via field network (can be the other way round as well).

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Note

Support of I/O modules (S500/S500-eCo) depends on the version of the library package. See the version details of the library in the release notes.