In industrial safety circuits, standard relays cannot meet the requirements of ISO 13849-1. They fail unpredictably. When a standard relay welds shut, the emergency stop button stops working. The machine keeps running. Operators are at risk.
The Siemens 3SK1111-1AB30 solves this problem. It is a safety relay built for emergency stop buttons, safety gates, and light curtains. Its job is simple but critical: when a safety device is triggered, this relay cuts power to the machine within milliseconds. No delay. No failure.
Feimu Technology supplies this unit to overseas system integrators and factory maintenance teams who need to pass safety inspections and protect their personnel.
Standard relays have one circuit. If that circuit fails, the relay stops working. The 3SK1111-1AB30 uses two internal circuits that monitor each other. This is called redundant design. If one circuit fails, the second circuit still opens the output contacts. The machine stops. Safety is maintained.
The contacts use silver-nickel alloy. This material resists welding. Even with frequent emergency stops, the contacts do not stick together.
Wiring uses spring terminals. No screwdriver needed for tightening. The spring holds the wire under tension. Vibration from nearby machines does not loosen the connection.
The housing has a physical barrier between the terminal area and the internal circuit board. Dust and metal shavings cannot reach the electronics. This matters in workshop environments where conductive dust causes short circuits.
| Parameter | Value |
|---|---|
| Product Model | Siemens 3SK1111-1AB30 |
| Series | SIRIUS 3SK1 Safety Relay |
| Width | 22.5 mm |
| Control Supply Voltage | 24V DC |
| Input Type | Single-channel (1-channel) |
| Output Contacts | 1 enable path (NO) + 1 signal path (NC) |
| Output Voltage Rating | 24V DC or 230V AC |
| Protection Rating | IP20 |
| Certifications | CE, UKCA, TUV, UL |
| Operating Temperature | -25°C to +60°C |
| Storage Temperature | -40°C to +80°C |
The 3SK1111-1AB30 responds to safety inputs within 20 milliseconds. This means from the moment an emergency stop button is pressed, the relay cuts output power in less than one cycle of 50Hz power.
Output contacts are rated to switch 6A at 230V AC. This is sufficient to directly control most contactors and small motor starters. No intermediate relay is needed.
Electrical life is rated at 100,000 operations at full load. For a machine that trips its safety circuit once per shift, this translates to over 10 years of service.
The relay accepts input from multiple safety device types:
Feimu Technology does not ship untested safety relays. Each Siemens 3SK1111-1AB30 goes through a verification process before leaving the warehouse.
Test records and Certificate of Origin are available upon request. Each relay carries a 12-month warranty from shipment date.
Safety relays are electromechanical components. They wear over time. Use this checklist every three months.
| Check Point | Method | Pass Condition |
|---|---|---|
| Terminals | Visual. Look for wires that have pulled back from spring terminals. | All wires fully inserted. |
| Housing | Visual. Look for cracks or dust buildup. | No cracks. Dust minimal. |
| Function test | Trip emergency stop 3 times. Measure stop response. | Machine stops within 1 second each time. |
| Indicator lights | Observe during function test. | Green LED on when reset. Off when tripped. |
| Reset button | Press reset after each trip. | Relay re-engages. Machine restarts. |
If the relay fails any test, replace it immediately. Do not attempt to repair internal components.
The Siemens 3SK1111-1AB30 has no mandatory replacement date printed on the housing. However, field data from Siemens indicates the following practical service life:
Feimu recommends replacing safety relays before they fail. Scheduled replacement is cheaper than accident investigation and machine downtime.
Q: Can I use a standard relay instead of this safety relay?
No. A standard relay has no redundant circuit and no self-monitoring. If the contact welds, the emergency stop does nothing. Safety inspectors check for this. Using a standard relay fails inspection and creates legal liability for the machine owner.
Q: Does this relay work with my existing emergency stop button?
Yes, if the button provides a normally closed contact. Most industrial emergency stop buttons do. Connect the button wires to terminals A1 and A2 in series. No additional components are needed.
Q: What happens if the internal coil fails while the machine is running?
The redundant design covers this. If the coil fails, the output contacts open. The machine stops. This is called fail-safe operation. A standard relay would stay stuck in the last state.
Q: Can I connect a light curtain to this relay?
Yes, if the light curtain provides a single OSSD output or a standard relay output. Connect the output to terminals A1 and A2. For two-channel light curtains, use the 3SK1112 model instead.
Feimu Technology started in Jiangmen, Guangdong in 2005. The company supplies original Siemens, Allen Bradley, GE, and Schneider components to customers in over 30 countries.
Contact:
Email: sales@feimutech.com
WhatsApp: +86 13358323579
Website: www.feimuplc.com
Response time: Within 24 hours. Technical questions typically answered within 12 hours.
Address
No. 26, Yuhu Street, Encheng Subdistrict, Enping City, Jiangmen City, Guangdong Province, China
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