Allen-Bradley Guardmaster & MSR127 Safety Relay Alternatives — the DAIDISIKE DA31 Cross-Reference

We keep cross-reference notes for the brands customers most often arrive with. On safety relays that means Allen-Bradley, because Rockwell itself keeps pushing buyers up its own ladder — from the older Minotaur MSR line to the Guardmaster GSR, and from fixed relays toward the software-configurable 440C-CR30. Every one of those migration prompts is also a moment to ask: do you actually need a premium modular system, or a single-function relay that does the one job cleanly? This page answers that, built the same way we do every cross-reference — from each manufacturer's public specifications, never their manual or logo.

A replacement assessment must identify the actual safety function, input structure, required safety contacts, reset behaviour, external device monitoring and target performance. Contact count and housing width are only an initial shortlist. In particular, DA31 EDM and monitored-manual reset equivalence are not established by the specification cited here. A resistance range for a mat or safety-edge input is not a contactor feedback specification. Where a required function is undocumented, leave the comparison open until the manufacturer supplies an applicable circuit and supporting data.

What is the DAIDISIKE equivalent of an Allen-Bradley Guardmaster GSR relay?

GSR SI, CI and DI require separate comparisons. Rockwell lists the 440R-S12R2 SI with two immediate safety relay outputs and one semiconductor signalling output; the latter is not an N.C. relay contact. The CI has a different output arrangement, and the DI adds two-input/system-linking functions. Consult the exact catalogue-number manual for reset, feedback and single-wire safety requirements.

DA31 published manufacturer data lists 24 V DC, dual-channel inputs, three N.O. safety contacts plus one N.C. auxiliary signalling contact, release response below 30 ms and a 22.6 mm body. These are useful comparison fields, but do not prove GSR reset, feedback or diagnostic compatibility. GSR expansion and logical interconnections are outside a simple DA31 substitution; retain their purpose in the revised safety-function design.

What can replace an Allen-Bradley Minotaur MSR127 (440R-N23126)?

An MSR127 comparison starts with the exact installed variant and wiring. The Minotaur MSR127 family includes different restart behaviours and supply/order variants. Record the complete catalogue number, connected contact or OSSD inputs, use of the auxiliary contact and external feedback wiring. The MSR126 is a related family, not permission to transfer an MSR127 circuit unchanged.

For DA31, compare the manufacturer-specified three safety N.O. contacts plus one auxiliary N.C. contact with the required loads. Its 24 V DC supply is not a substitute for an AC supply variant. Check its own environmental and enclosure ratings, and obtain the reset and diagnostic circuit details before concluding that an MSR126 or MSR127 function can be reproduced.

Cross-reference table: Allen-Bradley & Pilz single-function relays to the DA31

This table is a shortlist for engineering comparison, not a drop-in cross-reference. DA31 input/reset/feedback compatibility remains to be established for every row. Consult each exact order-number manual and retain a signed-off revised schematic.

Is the 440C-CR30 a relay, and when do you need a controller instead?

The Guardmaster 440C-CR30 is a software-configurable safety controller, not a single-function relay — reach for it (or a safety PLC) only when function count and logic justify the programming. The Allen-Bradley Guardmaster 440C-CR30 (440C-CR30-22BBB) carries 22 on-board safety I/O (6 configurable), runs on 24V DC (20.4–26.4 V) at about 5.28 W, is rated up to PL e / Category 4 / SIL CL3, is programmed in Connected Components Workbench (CCW), supports optional Micro800 plug-ins for standard, non-safety I/O, and has USB + RS-232. The Rockwell product profile distinguishes those expansion points from the on-board safety I/O. It exists to combine many E-stops, gates and light curtains with logic in one device — a job no single-function relay can do.

The DA31 is not a CR30 replacement. Even a small machine may need independent resets, muting, zone logic, diagnostics or safety networking. Compare the required cause-and-effect matrix and validation effort before deciding whether fixed-function relays or a controller are appropriate. The safety relay vs safety PLC selection guide develops that architecture decision.

How does the DA31 compare to a Pilz PNOZ S3 (and Siemens 3SK / Schneider Preventa)?

On the E-stop / safety-gate single-function role, the DA31 is a cross-shop alternative to the Pilz PNOZ S3, Siemens 3SK and Schneider Preventa relays — match by function and confirm outputs. The Pilz PNOZ S3 (PNOZsigma family) is a 24V DC relay with 2 N.O. safety contacts + 1 semiconductor output, positive-guided relays, dual-channel with cross-short detection, for E-stop and safety-gate monitoring, up to PL e / Category 4 and SIL 3, in a narrow 17.5mm body. Siemens SIRIUS 3SK relays cover E-stop / guard-door monitoring up to SIL 3 and PL e without programming, modular and expandable. The Schneider Electric Preventa (XPS) range offers single-function E-stop / safety-gate relays up to PL e / SIL 3 (confirm the exact XPS model's specs before citing numbers — we do not).

DA31 offers three safety N.O. contacts plus one auxiliary N.C. contact, while PNOZ s3 has two N.O. safety contacts and a semiconductor output. Its manufacturer-specified 22.6 mm width also differs from the 17.5 mm PNOZ s3. Neither contact count nor a shared target PL establishes interchangeability. In particular, a two-hand control needs its specified timing and anti-tie-down behaviour; do not infer that function from an E-stop relay comparison.

Which DA31 input fits a Type 4 light curtain or a safety gate?

Check the exact safety-input interface before connecting a curtain or gate. DA31 product data lists OSSD and door-interlock modes, but the applicable manual must establish wiring, test-pulse compatibility, fault detection and restart behaviour. Product data for the DQC hand-guard, DQT4 Type 4 curtain and DX-R1 switch can form the input-device comparison. Buying all components from one supplier does not establish the achieved PL of the complete stopping function.

Why source a Guardmaster equivalent from a China OEM?

Compare a written quote against the cost of a validated conversion. Ask DAIDISIKE for the exact DA31 revision, applicable manual, safety data and available certification documents, plus current lead time and price. Include wiring changes, contactor compatibility, engineering review and commissioning in the comparison with the installed Guardmaster. A lower component price does not remove the need to preserve every safety function.

Is naming these brands legal, and how do you keep the comparison honest?

These brands identify the products being compared; no affiliation or endorsement is implied. This article is a sourcing and engineering checklist, not a legal opinion or a declaration of compatibility. Competitor values must be traced to the exact order-number documentation, and DA31 capabilities must be supported separately by DAIDISIKE documentation.