Transferring Data With The Synchlink Module; Controllogix Synchlink Module Features; Related Documents - Rockwell Automation Allen-Bradley SynchLink 1756-DM Series Design Manual

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Publication 1756-TD008A-EN-P - August 2002

Transferring Data With the SynchLink Module

The SynchLink module transfers multiple types of reference data

between chassis, including:

· 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 daisy chain or ring configurations.

· Buffered - Data that exceeds the four word limit of a direct data

transfer. Buffered data is appropriately segmented at the

transmitting device and reassembled at the receiving device.

Buffered data cannot be automatically forwarded to the next

SynchLink node in the daisy chain or ring configurations. In this

case, transferring buffered data to the next node requires

intervention by the host controller.

· Axis data - Motion data used by the motion planner in the

controller. The 1756-SYNCH module can consume an Axis tag

from a controller and pass it over SynchLink or it can consume

an Axis tag received over SynchLink and reproduce it for the

local controller to consume. Axis data is not automatically

forwarded to the next node in daisy chain or ring configurations.

The SynchLink module offers the following features:

· Communication of remote axis data in a timely and

deterministic manner

· Communication of direct and buffered data

· Synchronization of CST and SynchLink clocks in the system

· Removal and insertion under power (RIUP) - Allows you to

remove and insert the module while power is applied.

· Class I Division 2, UL, CSA, and CE Agency Certification