Recommended Models & Related Products
Migration Note: The successor 3SK1111-1AB30 is from the newer 3SK1 series. While functionally equivalent, verify terminal layout, wiring diagrams, and panel space before substituting.
What's Included
Note: Safety sensors, contactors, and DIN rail are sold separately.
Why Buy From Us?
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In Stock – Limited remaining stock available
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Tested – Each unit verified for functionality
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Warranty Included – Purchase with confidence
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Technical Support – Safety circuit compatibility assistance available
Frequently Asked Questions (FAQ)
Q1: What is the Siemens 3TK2821-1CB30?
It is a SIRIUS 3TK28 series safety relay with 24 V AC/DC supply, 3 NO safety outputs, and 1 NC signaling output. It is used for monitoring E-stop circuits, safety doors, and position switches in industrial machinery .
Q2: Is this product still in production?
No. It is a discontinued product (phase-out started 2015) . It is available only through remaining stock or third-party suppliers.
Q3: What is the successor model?
The designated successor is 3SK1111-1AB30 from the SIRIUS 3SK1 series .
Q4: What safety rating does this relay achieve?
As a basic device, it achieves SIL 1 / PL c. When used as an expansion unit in a cascaded configuration, the system can achieve up to SIL 3 / PL e .
Q5: How many safety outputs does it have?
It has 3 Normally Open (NO) safety outputs (instantaneous) and 1 Normally Closed (NC) signaling output .
Q6: What is the difference between autostart and manual start?
Autostart: outputs energize automatically when the input circuit is closed. Manual start: operator must press a start button after the circuit is restored. The 3TK2821-1CB30 supports both modes .
Q7: Does this relay support dual-channel input?
Yes. It supports 1-channel or 1- and 2-channel sensor wiring .
Q8: What type of terminals does it use?
It uses screw terminals. For a spring terminal variant, see the 3TK2821-2CB30 .
Q9: What is the operating temperature range?
The range is -25 to +60 °C.
Q10: What is the country of origin?
Germany .
Q11: What should I verify before ordering?
Always verify the exact part number (3TK2821-1CB30), confirm that a discontinued product is acceptable for your maintenance application, check the condition and warranty of the specific unit offered, and consider whether the successor 3SK1111-1AB30 would be a better long-term choice.