Siemens SIRIUS Safety Technology
Siemens 3TK2828-1AL20 SIRIUS Safety Relay
A 230 V AC safety relay with two instantaneous and two adjustable time-delayed enabling contacts for coordinated Stop Category 0 and Stop Category 1 functions.
Product Overview
Immediate and Delayed Safety Shutdown
The 3TK2828-1AL20 evaluates safety-door and safety-sensor circuits and provides two instantaneous NO enabling contacts plus two delayed NO enabling contacts. One instantaneous NC contact provides signaling.
Opening the sensor circuit removes the instantaneous enabling paths first. The delayed paths open after the selected 0.5 to 30 second interval, supporting a controlled stopping sequence before final isolation.
| Manufacturer | Siemens |
|---|---|
| Order number | 3TK2828-1AL20 |
| Product family | SIRIUS 3TK28 |
| Product type | Time-delayed safety relay |
| Terminal system | Screw terminals |
| Mounting | 35 mm mounting rail; any mounting position |
| Start mode | Automatic start |
Product Specifications
Verified Technical Data
| Rated control supply | 230 V AC, 50/60 Hz |
|---|---|
| Instantaneous outputs | 2 NO |
| Delayed outputs | 2 NO, adjustable 0.5-30 s |
| Signaling output | 1 NC |
| Stop functions | Stop Category 0 and Stop Category 1 |
| Instantaneous safety level | SIL 3; PL e; Category 4 |
| Delayed safety level | SIL 2; PL d; Category 3 |
| PFHD | 2.7 x 10-9 per hour |
| Thermal current | 5 A |
|---|---|
| AC-15 rating | 5 A at 230 V AC |
| DC-13 rating | 5 A at 24 V DC |
| Mechanical cycles | 10 million |
| Electrical cycles | 100,000 |
| Operating temperature | -25 to +60 °C |
| Product dimensions | 45 x 106 x 115 mm (W x H x D) |
| Net weight | 0.599 kg |
Features & Benefits
Product Functions
Two-stage shutdown
Immediate and delayed contact groups support coordinated stopping.
Adjustable off delay
The delayed outputs are adjustable from 0.5 to 30 seconds.
Two-channel evaluation
Safety inputs support cross-circuit monitoring.
Automatic start
The exact -1AL20 version uses automatic start.
Immediate signaling
One NC contact provides status signaling.
Status indication
Five LEDs provide device operating information.
Applications
Industrial Application Scope
Controlled machine stopping
Stop Category 1 sequences before delayed isolation.
Protective-door monitoring
Guard circuits requiring immediate and delayed enabling paths.
Safety mats
Safety-mat circuits using the supported sensor arrangement.
Lifecycle & Replacement
Official Product Status
Product Technical Images
Shutdown Timing Schematic
The instantaneous contacts open when the safety input changes state. The delayed contacts open after the configured interval.
Functional timing schematic based on Siemens output and delay data. Not to scale.
FAQ
Frequently Asked Questions
Is 3TK2828-1AL20 discontinued?
Yes. Siemens identifies it as a phased-out product.
What is the preferred successor?
Siemens specifies 3SK1121-1CB42 together with power module 3SK1230-1AW20.
Is the replacement a direct swap?
No. The successor requires different hardware and terminal mapping.
What is the adjustable delay range?
The off-delay range is 0.5 to 30 seconds.
Which outputs are time delayed?
The delayed enabling contacts are 47-48 and 57-58.
Recommended Products
Contact Information
Industrial Parts Enquiry
Send the exact model, quantity and destination for a quotation.
ManagerLeonia
Emailsales@mvme.cn
Whatsapp+8618030175807
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