Dual-Channel Two-Hand Monitoring With Automatic Start - GE RSTi-EP Functional Safety Manual

7.6 Dual-channel Two-hand Monitoring with Automatic Start

Achievable safety rating
Stop category
Features
Safety sensor/operating
mechanism
Notes
Note: All example applications shown are proposals without warranty. In any case the operator has
to perform a safety review of the entire site.
If one or both switches of the 2-hand switch are released, the EP-19xx switches off the 24-V supply
for the modules (switchable modules refer to the section, General Contact Information) inside the
safety segment and thus also for contactors K3 and K4. The failure of a switching element in the two-
hand switch or a cross-circuit in its supply lines does not result in the failure of the emergency stop
mechanism and is
detected within the fault-reaction time. An interruption of the NC contact by S2 is detected before the
next switching cycle and by S1 when the power is switched on.
The EP-19xx module switches on the 24-V supply for the following modules within the safety
segment if:
•
Two-hand switch is pressed synchronously within 0,5 seconds
•
Feedback circuit (NC contacts of K3 and K4) is closed
Contactors K3 and K4 are controlled by the PLC and can switch on as soon as the EP-19xx has
switched on the 24-V supply. To reset the system, press the reset button within 0.1 to 2 sec after
switching on the power supply, even when automatic reset is used.
GFK-2956A
Cat. 4 DIN EN ISO 13849-1
PLe DIN EN ISO 13849-1
SIL3 IEC 62061/61508
0 EN 60204-1
• Dual-channel monitoring
• Cross-connection detection
• Automatic reset
• Monitoring of external contactors (EDM)
Two-hand switch
The application must be compatible with
the automatic start-up function.
November 2017
Chapter 7. Example Applications
51