The Allen-Bradley Guardmaster GuardLink system is a single-cable safety connection network: up to 32 safety devices — E-stops, interlocks, light curtains — daisy-chain to a DG safety relay, replacing the point-to-point home runs of a traditional hardwired safety circuit. Each tap reports its state back over the link.

GuardLink or point-to-point safety wiring?

One cable links all the taps, and a fault appears as a tagged tap with its location known at the relay — no hunting through a bundle. A traditional hardwired safety loop needs a home run per device, multiplying cable and terminations and hiding the fault inside the panel. Choose GuardLink when the safety devices spread across a cell rather than clustering at one relay.

What does the DG safety relay actually do?

The 440R-DG2R2T aggregates the taps, drives the machine safe outputs, and connects via the 440R-ENETR module to EtherNet/IP for diagnostics in Studio 5000. It turns a pile of discrete safety contacts into one monitored node. The alternative — a separate safety relay per device — multiplies relays and leaves no network visibility of which door opened.

How safe is the link itself?

GuardLink is rated SIL3 / PL e, and it pulse-tests its inputs to detect cross-wiring and short-to-ground faults that a plain safety PLC node would miss. That holds the protection level while cutting the wire count. The alternative — a basic safety PLC input per door — adds cost and configuration for the same function.