SKU: 1756-SYNCH

Allen-Bradley 1756-SYNCH Synchlink Communication Module

The Allen-Bradley 1756-SYNCH is a ControlLogix SynchLink module providing 5 Mbps fiber-optic communication. It enables precise time synchronization and high-speed data broadcasting between multiple chassis for coordinated motion control.

The Allen-Bradley 1756-SYNCH serves as a specialized SynchLink communication interface for the ControlLogix platform. This module enables high-speed data broadcasting between multiple controller chassis. It primarily facilitates time synchronization for complex motion control tasks. By establishing a dedicated fiber-optic link, the module ensures that distributed controllers share axis data simultaneously. This hardware is essential for applications requiring microsecond-level coordination across separate hardware racks.

Communication Performance

Data transmission occurs over a stable fiber-optic medium at a consistent rate of 5 Mbps. The module utilizes a highly efficient 50 μs frame speed to minimize latency. Each data frame consists of 30 total bytes, including flags, control bits, and a 24-byte payload. A 2-byte Cyclic Redundancy Check (CRC) field validates every transmission to prevent data corruption. These features allow the system to maintain a synchronized time base across the entire automation network.

Technical Specifications

Attribute	Specification
Backplane Current (5.1V DC)	1200 mA
Backplane Current (24V DC)	3 mA
Power Dissipation	6.2 Watts
Thermal Dissipation	21.2 BTU/hr
Operating Temperature	0 to 60°C (32 to 140°F)
Fiber Optic Ports	2 (Transmitter and Receiver)

Integration and Connectivity

The 1756-SYNCH supports fiber-optic cable lengths reaching up to 300 meters. Users should utilize 200/230 micron HCS cables to ensure signal integrity. The module remains compatible with both standard and redundant ControlLogix power supply configurations. Furthermore, the hardware survives industrial shocks up to 30g during active operation. This durability makes it suitable for demanding factory floor environments where precision remains critical.

Operational Requirements

Optimal performance requires clean and dry industrial conditions to prevent fiber-optic port contamination. Engineers typically pair this module with 1403-CFxxx series cables for reliable chassis-to-chassis links. Although Rockwell discontinued this specific model in 2012, it remains a vital legacy component for existing motion systems. It provides the high-bandwidth backbone necessary for electronic gearing and camming applications.