Instructions
Basic Operation 20
Doc: HMSI-27-314, Rev. 3.10Anybus Communicator EtherNet/IP / Modbus-TCP User Manual
2.3 Sub-network Protocol
2.3.1 Protocol Modes
The Anybus Communicator features three distinct operating modes for sub-network communication:
‘Master Mode’, ‘DF1 Master Mode’ and ‘Generic Data Mode’. Note that the protocol mode only spec-
ifies the basic communication model, not the actual sub-network protocol.
•Master Mode
In this mode, the gateway acts as a master on the sub-network, and the serial communication is
query-response based. The nodes on the network are not permitted to issue messages unless first
addressed by the gateway .
For more information about this mode, see “Master Mode” on page 21.
• DF1 Master Mode
In this mode, the gateway acts as a master on the sub-network, using the DF1 protocol. The serial
communication is query-response based. For more information about this mode, see “DF1 Pro-
tocol Mode” on page 86.
• Generic Data Mode
In this mode, there is no master-slave relationship between the sub-network nodes and the gate-
way; any node on the sub-network, including the gateway, may spontaneously produce or con-
sume messages.
For more information about this mode, see “Generic Data Mode” on page 22.
2.3.2 Protocol Building Blocks
The following building blocks are used in Anybus Configuration Manager to describe the sub-network
communication. How these blocks apply to the three protocol modes is described later in this document.
•Node
A ‘node’ represents a single device on the sub-network. 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
(see below). Each transaction is associated with a set of parameters controlling how and when to
use it on the sub-network.
• Commands
A ‘command’ is simply a predefined transaction stored in a list in the Anybus Configuration Man-
ager. 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.