SICK RLY3-EMSS300 Safety Relay Manual

Calculation formula:

T total=T sensor+TRLY three+T contactor+T braking 

T total=T sensor+T RLY3+T contactor+T braking

Example: Assuming an emergency stop sensor response time of 5 ms, RLY3-EMSS300 maximum of 12 ms, contactor release time of 20 ms, and braking time of 50 ms, the total shutdown time is approximately 87 ms. According to ISO 13855, the safety distance

S=K×T+C

S=K × T+C, where K=1600 mm/s, then S ≥ 1600 × 0.087+C ≈ 139 mm+C. This value needs to be compared with the specific application.

5.4 Effects of Test Pulses

Test pulse width of 2 ms with an interval of 40 ms. These pulses appear on T1/T2/T3 and may be mistaken for signal jitter by some fast response electronic sensors. For electromechanical contact sensors (emergency stop, door switch), a 2 ms pulse will not cause contact misoperation because the bounce time of mechanical contacts is usually greater than 2 ms. If a solid-state output safety light curtain is connected, it is necessary to confirm whether its output can tolerate test pulses, otherwise cross circuit detection should be disabled (changed to single channel or use pulse free power supply).

Certification, Standards, and Compliance

RLY3-EMSS300 holds the following important certifications to ensure its availability in major global markets:

EU Declaration of Conformity (CE)

UK Declaration of Conformity (UKCA)

ACMA Declaration of Conformity (Australia)

CULus Certificate (North America)

CCC Certificate (China)

UK Type Examination Approval

China RoHS Compliance

Its electromagnetic compatibility complies with IEC 61000-6-4 (emission), IEC 61326-3-1 (immunity, industrial applications), IEC 61000-6-2, and IEC 60947-5-1. Users can integrate into standard industrial environments without the need for additional EMC testing.

Alternative and selection suggestions

When encountering equipment replacement or new project selection, attention should be paid to:

RLY3-EMSS300 has a single width of 18mm, which can save control cabinet space.

If the application requires independent manual reset and EDM to coexist, please choose other SICK models (such as RLY3-OSSD series).

If the safety sensor is of OSSD output type (such as light curtain), RLY3-EMSS300 is not suitable because its input requires passive contacts. At this time, RLY3-OSSD or UE series should be selected.

The attachment information can be found at www.sick.com/ReLy.

Maintenance and lifespan management

Despite the device's task time of up to 20 years, regular functional testing is still required:

Trigger each safety function at least once a month (press emergency stop, open protective door), confirm that the safety output is reliably disconnected and the reset logic is normal.

Check the LED indicator lights to ensure there are no abnormal flashes.

Measure the contact resistance of the safety output contacts with a multimeter once a year. If it exceeds 100 m Ω and the switching frequency is high, preventive replacement should be considered.

For outputs directly connected to inductive loads (contactor coils), freewheeling diodes or surge suppressors should be connected in parallel at both ends of the load to extend the contact life.