Safety circuit relay for emergency-off
The Siemens 5TT5200 is a SENTRON emergency-off relay — a safety-rated device that monitors E-stop pushbuttons and position switches and drops its output contacts when the circuit opens. It is built to EN 954-1 category 4, meaning it can tolerate a single fault without losing the safety function and the fault is detected at the next demand. The relay carries a 5 A AC-1 resistive rating on the CO contact and 3 A AC-15 on the NO contact, which covers pilot-duty loads like contactor coils in the safety chain. The NC contact is rated 2 A AC-15 and 4 A DC-13, so it can switch a DC solenoid or indicator lamp directly.
The relay includes a start input and a feedback input, so it can be wired for monitored manual restart after an E-stop event. Position-switch monitoring is built in; proximity-switch and valve monitoring are not supported on this basic device.
Recovery time and operating limits
Recovery time is 500 ms — the interval after the safety circuit is restored before the relay will re-energise. This prevents rapid cycling if the E-stop is released and re-pressed quickly. Maximum operating frequency is 600 cycles per hour. The coil draws 3.5 VA at the rated AC supply. The relay operates on 50/60 Hz supply and accepts 184–253 V AC at both frequencies, so it runs on standard 230 V line voltage with tolerance for brownout conditions. Ambient operating range is 0 °C to 50 °C — suitable for indoor panel environments but not for unheated enclosures in freezing conditions.