The IEC 60870-5-101 protocol is a serial based communications protocol. The protocol is designed for use on systems that use permanent direct connections between the Controlling Station (SCADA master) and the Controlled Station(s) (outstations or slaves, including ClearSCADA).
Communications can be either:
- Balanced—whereby there is a one-to-one full duplex connection between a channel and an individual slave outstation
- Unbalanced—whereby there is a half-duplex connection between a channel and one or more slave outstations (for instance, in a multi-drop setup). With unbalanced communications, it is also possible for other slaves (not necessarily ClearSCADA slave outstations) to be connected to the transmission media to which the channel is connected.
For more information on either of the above transmission procedures, see Configure IEC 60870-5-101 Protocol Properties.
When communicating using the IEC 60870-5-101 protocol, a channel will typically have a Serial Connection Type (specified on the Connection tab of the IEC 60870-5 Slave Direct Channel Form) and use these settings:
- Data Bits—Should be set to 8 bits.
- Parity—Should be Even, to comply with the IEC 60870-5 standard.
If no parity is used (for instance, if the communications media does not support parity), be aware that this increases the likelihood of an error going undetected.
- Flow Control—Generally specify None to comply fully with the IEC 60870-5 standard. However, be aware that some form of Flow Control may be required by transmission media that is not fully compatible with the IEC 60870-5 standard.
(Specify a different Connection Type if the serial interface is not directly connected to ClearSCADA—for more information, see Tabs on Channel Forms in the ClearSCADA Guide to Advanced Drivers.)
You also need to Configure IEC 60870-5-101 Protocol Properties on the IEC 60870-5 tab.