Subnetwork Protocol; Protocol Modes; Protocol Building Blocks - HMS Anybus Communicator User Manual

2.3 Subnetwork Protocol

2.3.1 Protocol Modes

The Anybus Communicator features three distinct modes of operation regarding the subnetwork com-
munication, called "Master Mode", "Generic Data Mode" and "DF1 Master Mode". Note that the pro-
tocol mode only specifies the basic communication model, not the actual subnetwork protocol.
• Master Mode
In this mode, the module acts as a master on the subnetwork, and the serial communication takes
place in a query-response fashion. The nodes on the network are not permitted to issue messages
unless they have been addressed by the module first.
See also "Master Mode" on page 19.
• Generic Data Mode
In this mode, there is no master-slave relationship between the subnetwork nodes and the mod-
ule; any node on the subnetwork, including the Anybus Communicator, may spontaneously pro-
duce or consume messages.
See also "Generic Data Mode" on page 20.
• DF1 Master Mode
In this mode, the module acts as a master on the subnetwork, using the DF1 protocol. The serial
communication takes place in a query-response fashion.
See also "DF1 Protocol Mode" on page 76.

2.3.2 Protocol Building Blocks

The following building blocks are used in Anybus Configuration Manager to describe the subnetwork
communication. How these blocks apply to the three protocol modes will be described later in this doc-
ument.
• Node
A node represents a single device on the subnetwork. Each node can be associated with a num-
ber of transactions, see below.
• Transaction
A "transaction" represents a complete serial telegram, and consists of a number of frame objects
(below). Each transaction is associated with a set of parameters controlling how and when to use
it on the subnetwork.
• Commands
A "command" is simply a predefined transaction stored in a list in the Anybus Configuration
Manager. This simplifies common operations by allowing transactions to be stored and reused.
• Frame Object
"Frame objects" are low level entities used to compose a transaction (see above). A frame object
can represent a fixed value (a constant), a range of values (limit objects), a block of data or a cal-
culated checksum.
Anybus Communicator PROFINET User Manual
Basic Operation 18
Doc: HMSI-27-309, Rev. 3.11