Master Station Versions and WITS Versions
The WITS-DNP3 Protocol standardises the communications between a Field Device and a Master Station. As can be seen from the Device Catalogue there are a large number of Field Devices implementing different versions of the WITS-DNP3 Protocol, however there are currently only two Master Stations. ClearSCADA from Schneider Electric and Scope from Servelec.
To assist WITS members in determining supported versions of WITS-DNP3 Protocol the following table of Master Station version against WITS-DNP3 Protocol version has been produced. Although it may be possible to determine the same information from the Device Catalogue on the WITS website, these tables have been produced as a convenience and will be kept up to date. Both tables start with the first version of the Master Station to support WITS.
Although both current Master Stations support all versions of WITS up to their latest supported version, this may not always be the case. It is possible that current Master Stations and future Master Stations may implement a selection of WITS versions and not all versions. On this basis the tables below are presented as grids showing which versions are supported.
Readers may assume that any Master Station version not listed, but higher than a listed version in the table will support the WITS versions identified for the lower listed version. So for example ClearSCADA 6.73 would support the same WITS versions as the lower 6.72 which is listed in the table.
Schneider Electric ClearSCADA versions against WITS Versions
Servelec Scope versions against WITS versions
Note that WITS version number 1.0 is not shown as this was never formally released for general use. The lowest version a Field Device could implement is WITS 1.1.
Field Device vendors should note that just because a Master Station supports a later version of the protocol, this does not necessarily mean that the later version of the protocol is available in all user’s estates. It can take users many months or years to schedule an upgrade to their telemetry systems and so it is incumbent on vendors to check which versions of Master Station are in use by their prospective clients, or ensure that they implement multiple versions of the protocol so that their Field Devices can be used by users who are operating an older version of Master Station.