Rockwell Automation 1756-DMF30 ControlLogix Drive Module - Manual (Page 31)

Publication 1756-UM522B-EN-P - February 2003
Drive Module Features 3-5
Each of these features is described in this section, including
information on which RSLogix 5000 and DriveExecutive configuration
screens should be used to configure the feature. For an overview of
the entire configuration process, see Chapter 5, Configuring the Drive
Module.
Controller Communication Format
The controller communications format defines the connection
between the owner-controller and the module (i.e. determines what
type of data is transferred between them). The 1756-DMD30 module
supports Velocity Control, Position Control, User-Defined and Custom
User-Defined communication formats. The 1756-DMF30 supports the
User-Defined communication format.
SynchLink Communications Format
The SynchLink communications format defines the connection at the
SynchLink Receive Port and the SynchLink Transmit Port. It
determines the type and number of data type in each connection.
SynchLink messages are structured as six 32-bit words; the words are
divided into three types:
•
Direct - Data delivered in a single message. A SynchLink
message can contain a maximum of four direct data words; each
word is 32 bits in length. Direct data can be automatically
forwarded to the next node in the daisy chain and ring
configurations.
•
Buffered - Data that exceeds the four word limit of a direct data
transfer. A maximum of 18 buffered are transfered every 500
µ
S.
Buffered data is appropriately segmented at the transmitting
module and reassembled at the receiving module. Buffered data
cannot be automatically forwarded to the next node in the daisy
chain and ring configurations.
•
Axis - the Drive module does not support this data type.
Multiple Port Communications Formats in Single Module
You must set a communications format for receiving data (Receive
Port Communications Format) and transmitting data (Transmit Port
Communications Format) in each SynchLink node.