IEC60870-5-104 Multiple Connections¶
An AC500 with more than one substation connection must be able to identify the corresponding control station clearly. This identification takes place exclusively via the control station’s IP address. In order to make it possible for a non-redundant control station to have redundant access to a substation with 2 ETHERNET connections. The local substation address is ignored during connection establishment.
In the following descriptions, the term station must not be confused with the individual connection. One station can have several connections. An IEC60870-5-104 communication always takes place between a control station and a substation. A control station can manage several substations and also simultaneously be a substation for one or several control stations. However, these must then be realized using different stations.
A PLC may not be configured for another PLC repeatedly as a substation or a control station unless a disjunctive ETHERNET infrastructure is used for this.
Redundant connections must be specified as such in the configuration.
An AC500 can be used only once as control station for another AC500, it makes no sense to use the same AC500 repeatedly as a control station for the same substation. Such a structure is configured as a redundant control station as long as only one AC500 exists as a control station per substation. However, this control station may have 2 IP addresses. Therefore, this configuration must either have the IP address 0.0.0.0 entered on the substation for the control station, meaning that all IP addresses are accepted and no other control station can access this AC500 or alternatively the possible control station addresses must be specified (ETH1 and ETH2).
Tree constellation (PM57x-/ PM58x-/ PM59x-ETH, PM5650-2ETH)
If you plan to control several substations with the AC500, they can be cascaded. This results in a tree structure.
| 2 control stations | |
| Substation and 3 control stations | |
| Substation and 3 control stations | |
| Substation | |
| Substation |