Siemens SIRIUS 3RK3 - Two-Hand Operation;Synchronism

other safety sensors/functions, the need for a monitored start command depends on the risk
assessment.
If the START button is actuated for more than 2 seconds, the safety relay detects a wiring short
circuit in the START button and the associated function element remains in the safe state.
„1“
„0“
,1
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Figure 3-7 Start function "Monitored start"
WARNING
Restarting the system
Can Cause Death, Serious Injury, or Property Damage.
The start type depends on the risk assessment. For PL e n accordance with EN ISO 13849‑1 as
well as SIL 3 in accordance with IEC 61508, the monitored start must be used in the case of
EMERGENCY STOP, for example. For other safety sensors/functions, the need for a monitored
start command depends on the risk assessment.
3.7.3.8 Two-hand operation/synchronism
Synchronous sensor operation is a special form of simultaneity of sensors.
In this case, it is not su󹪟cient for buttons 1 and 2 to be switched to the closed state "at di󹪜erent
times". Instead, the buttons must be actuated within 0.5 seconds of each other. Before
monitoring, a button is considered to have been operated if all the button's sensor contacts are
closed and no fault (e.g. discrepancy, cross-circuit, etc.) has been detected.
Synchronism of sensors is required, in particular, in the case of two-hand operation of presses.
This ensures that the presses only become active when the sensors are operated simultaneously
with both hands. This minimizes the risk of the operator getting a hand in the press.
With the safety relays, you can achieve applications up to type IIIc acc. to EN 574 or EN ISO 13851
(applications up to PL e / Cat. 4 acc. to EN ISO 13849-1 or SIL 3 acc. to IEC 61508).
Note
The safety relays support two-hand operator panels with the following contact arrangements:
• Two-channel normally open contact (NO)(NO)
• Four-channel normally open contact (NONO)(NONO)
• Four-channel normally open/normally closed contact (NONC)(NONC)
Note
The two-hand circuit must be marked in compliance with EN 574 or EN ISO 13851. You can 󹪝nd
information on determining the response time in Section Response times (Page 171).
Overview
3.7 Safety systems - General information
SIRIUS 3RK3 Modular Safety System
56 Equipment Manual, 07/2020, NEB926253002000/RS-AC/006