Relay Contact Protection - Allen-Bradley 1444-TSCX02-02RB User Manual

Chapter 2 Install the Dynamix 1444 Series Monitoring System
40
WARNING: Connecting the RIGHT sides of two main modules could result in
damage to the modules and unexpected or improper operation of any
connected expansion modules.
The Local Bus Extension cables are designed (keyed) to allow connection of the
RIGHT side of any main module to the LEFT side of any main or expansion
module as shown in this image.
Any other connection that results in the RIGHT sides of two
MAIN MODULES (1444-DYN02-01RA) being connected is not
allowed, including when one or more expansion modules are
between them.
Improper arrangement: Connects the right side of two main modules.

Relay Contact Protection

Measures to limit contact wear and arcing across the contacts of a mechanical
relay are highly dependent on the following:
• The current and voltage being switched and whether AC or DC
• The load type (resistive or inductive)
• System factors such as wiring
Due to this application dependency, it is not possible to integrate contact
protection circuitry within the Dynamix hardware. It remains the system
designer's/installer's responsibility to take appropriate external measures to
mitigate these risks that are based on the reliability and functional safety
requirements that can apply. Commercial surge suppressors (often DIN rail
mounting) can be based on RC, MOV, or Diode protection methods. In
general, it is recommended to provide protection equipment close to its
originating source.
Rockwell Automation Publication 1444-UM001D-EN-P - June 2018