Keylock Actuation in 3SU1 22mm Panel Bodies: Confirming RONIS I>O<I Mechanical State Before BOM Lock
The Siemens A6X30137900 is a momentary keylock switch body in the 3SU1 series. It ships as a non-illuminated actuator head only — no contact block included. Panel fit is 22.3mm round cutout, compatible with Siemens 22mm operator interface hardware. The RONIS lock delivers a three-position I>O<I throw (left locked, center off, right locked); returning to center on key release makes this suitable for access-interlock scenarios where the operator must intentionally rotate and release to re-enable a machine mode.
If you are cross-referencing a legacy 3SB/3SX keylock or searching for a RONIS-sourced equivalent, the other names in the Siemens cross-reference table include 3SU10304BM010AA0-Z, 3SU1030-4BM01-0AA0-Z, and the legacy code 5779489 — but the on-page MPN is the sourcing anchor.
On-page parameter snapshot
- Series: 3SU1
- Actuator Type: Keylock (RONIS)
- Throw: I>O<I (three-position; center maintained off)
- Type: Momentary
- Illumination: Non-Illuminated
- Panel Cutout: 22.3mm (Round)
- Requires: Contact Block(s) (sold separately)
- Package: Box
- Status: Active
- RoHS: ROHS3 Compliant
Why a panel builder picks this body vs. a selector
The A6X30137900 is a keylock actuator — it requires a physical key to rotate the throw. The position stops are mechanical; the center position is a stable dead-center between two locked sectors. This suits safety interlock applications where unauthorized personnel cannot nudge the switch with a finger or tool. The A6X30137900 is momentary in the sense that releasing the key returns the actuator to center, but the blocking detents at the end positions require deliberate key rotation to engage.
What you must confirm before ordering
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Contact block type: This body snaps onto Siemens contact blocks (sold separately). Verify that your existing contact block — typically a 3SU1 2-position or 3-position front-mount block — is compatible with a keylock-style actuator head. Selector and keylock bodies share the same mounting interface, but not all contact blocks ship pre-configured for keylock throw geometry.
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Key removal position: The RONIS mechanism on this body locks at both end positions; the key can be removed in the center position only. If your control philosophy requires key removal at the end positions (fully clockwise or counterclockwise), a different RONIS variant is required.
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Mounting depth: The keylock mechanism projects above the bezel plane more than a standard selector knob. Verify that your enclosure depth or protective cover clearance accommodates the extended RONIS cylinder.
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Legacy cross-reference: If replacing a 3SB- or 3SX-series keylock, the 22.3mm cutout dimension carries forward — but the mounting collar geometry changed. A 3SU1 body cannot be dropped into a 3SB collar housing without adapter hardware or a panel modification. Confirm the series migration path before committing to the order.
Bench engineer's notes from raw specs
Treat the raw specification table as authoritative for siemens A6X30137900 (KEY-OPERATED SWITCH RONIS. I>O<I); category path: Switches > Configurable Switch Components > Configurable Switch Bodies; confirmed specs: series: 3SU1; Type: Momentary; Package: Box; Product Status: Active. Cross-check electrical limits, mounting style, output type, and lifecycle status against the target panel or machine design before freezing the BOM line or authorizing a field swap.
Field notes — install and commissioning
Before energizing or replacing the module, align cabinet power rails, wiring plan, load type, terminal layout, and temperature class with both the manufacturer documentation and the as-built BOM.
Selection notes for footprint and electrical verification
Approve this line only when MPN, manufacturer, series, supply voltage, I/O style, mounting, and application role match the design intent. For alternates, diff the same fields first, then validate software/project hooks.