Differences HA-Modbus TCP (V2/ V3) and HA-CS31¶
The following table gives an overview of the different High Availability variants possible with AC500.
The figures are indicative, depend on chosen architectures, system size, network and CPU/CM modules used.
| Library version | HA-CS31 | HA-Modbus TCP | ||||||
| CPU version | V2 CPUs | V2 CPUs | V3 CPUs | |||||
| IO Communication | Parallel serial | ETHERNET | ETHERNET | |||||
| CPUs | PM573 - 595 | PM573 | PM591 | PM595 | PM5630 | PM5650 | PM5670 | |
| IO network is based on ETHERNET and external redundancy mechanism | ||||||||
| Max. system size IO clusters1, 6) | 3 - 50 2) | 3 | < 25 / 50 | < 60 / 92 | < 30 | < 50 | < 100 | |
| IO Modules | CI590:S500 usable | CI52x: S500 and S500-eCo usable 4) | ||||||
| Switch-over times | CPU | 25 -120 ms 3) | ~70 ms 6) | |||||
| Field | 15 - 20 ms | Depends mainly on external switches redundancy mechanism: e.g. MRP typ. 150 ms + Modbus cycle time e.g. 40 ms | ||||||
| SCADA connectivity | OPC DA, IEC60870, … | OPC DA, IEC60870, … | OPC DA, OPC UA, IEC60870, … | |||||
| Programming | Codesys V2.3 | Codesys V2.3 | Codesys V3.5 | |||||
| Interfaces | Several CS31 and ETHERNET interfaces | Several ETH ports, via CM597 | 2 Eth ports 5) (+ 1 CAN Interface) | |||||
| Overview of AC500 HA system alternatives | ||||||||
1) Number of I/O clusters recommendation based on performance or max. number of sockets (CPU and CM modules )
2) Limited by CPU performance, number of CM574 modules number of CS31 clients and process data limits.
3) Depends on system size and CPU type
4) Some S500-eCo modules not yet usable, see release notes
5) Communication Module not available