Application Example For Sto Function (Cat. 3, Pl D) - Beckhoff EL72 1-901 Series Manual

Integrated safety
6.2.4

Application example for STO function (Cat. 3, PL d)

Application example (STO – Safe Torque Off)
The following application example shows how the EL72x1-9014 can be wired together with an EL2904 in
order to implement an STO function according to EN 61800-5-2.
The user must realize an appropriate evaluation for the wiring between the safety output terminal (EL2904)
and the servo terminal (EL72x1-9014), so that a fault exclusion is permissible for external supply and cross-
circuit in this wiring.
Components involved
• Emergency stop device (control switch S1) according to ISO 13850 and control switch S2
• 1 safety input terminal (EL1904) and 1 input terminal (EL 1004)
• 1 safety output terminal (EL2904)
• 1 safety logic terminal (EL6900) with function block "ESTOP"
• 1 servo terminal (EL72x1-9014) with STO input
• Programmable logic controller (PLC) and EtherCAT fieldbus
A safety door (S1 and S2) and a restart signal (S3) are logically linked on an ESTOP function block. The
EStopOut signal is transferred to the NC controller, with which, for example, the Enable signal of the
EL72x1-9014 can be switched. The STO input of the EL72x1-9014 is operated via the delayed output
EStopDelOut. The EL72x1-9014 supplies the information that the STO function is active via the standard
controller. This information is transferred to the EDM input of the ESTOP function block and additionally to
the EDM function block in order to generate an expectation for this signal.
180 Version: 1.9 EL72x1-901x