DF1

There is no DF1 driver you can connect with. DF1 currently exists as a protocol specification and a generated read/write model only - there is no df1 connection code in any of the language ports, so there is nothing to put a connection string into. This page is kept for reference and is not linked from the navigation.

Allen-Bradley’s DF1 is the serial protocol used by the SLC-500 and PLC-5 family, and by the MicroLogix controllers over their RS-232 port.

What exists today

The protocol is described in protocols/df1/src/main/resources/protocols/df1/df1.mspec and code is generated from it for Go, under plc4go/protocols/df1/readwrite. The generated model covers the symbol/framing layer and the unprotected read exchange:

  • DF1Symbol with the DF1SymbolMessageFrame, DF1SymbolMessageFrameACK and DF1SymbolMessageFrameNAK variants

  • DF1Command with DF1UnprotectedReadRequest and DF1UnprotectedReadResponse

  • a CRC helper in StaticHelper.go, exercised by its own unit test

This model is verified by a ParserSerializer test suite (plc4go/assets/testing/protocols/df1/), so the wire format is known to round-trip - but nothing builds a connection, transport or tag handler on top of it.

Related: AB-ETH

The DF1 command layer is reused by the AB-ETH driver, which tunnels DF1 commands inside CIP encapsulation over Ethernet. That is a working driver in Java, and it is what you want if your device is reachable over Ethernet rather than a serial port. The DF1 message types it uses are generated into the ab-eth module rather than shared from here.

Contributing

A DF1 driver would need a serial transport binding, the framing/ACK-NAK state machine on top of DF1Symbol, and a tag address syntax for the SLC/PLC-5 data-file notation (e.g. N7:0). The protocol layer is the part that already exists, so a contribution can start at the driver logic. Please raise it on dev@plc4x.apache.org before starting.