2.2
Intended use
The CMMT-AS-...-S1 supports the following safety functions in accordance with EN 61800-5-2:
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Safe torque off Safe torque off
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Safe brake control Safe brake control
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Safe stop 1 Safe stop 1, achievable with suitable safety relay unit and appropriate connection of
the servo drive
The safety function STO is intended to disconnect the torque of the connected motor, thereby prevent-
ing an unexpected restart of the motor.
The safety function SBC is intended to safely hold the motor and axle in their position at standstill.
The safety function SS1 is intended for rapid stop with subsequent torque switch off.
2.2.1
Application areas
Safety functions may only be used for applications for which the stated safety values are sufficient
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9.1 Technical data, safety equipment.
2.2.2
Permissible components
The logic supply must meet the requirements of EN 60204-1 (protective extra-low voltage, PELV).
If holding brakes and clamping units without certification are used, the suitability for the related
safety-oriented application must be determined through a risk assessment.
The motors must fulfil the requirements of EN 61800-5-2 appendix D.3.5 and D.3.6 and of
EN 60204-1. Motors approved or specified by Festo for the CMMT-AS fulfil the requirements.
The motor cables and brake lines must fulfil the requirements of EN 61800-5-2 appendix D.3.1 and of
EN 60204-1. Motor cables and brake lines approved by Festo for the CMMT-AS fulfil the requirements.
2.3
Foreseeable misuse
Foreseeable misuse, general
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Use outside the limits of the product defined in the technical data.
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Cross-wiring of the I/O signals of more than 10 servo drives CMMT-AS.
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Use in IT networks without insulation monitors for detection of earth faults.
When operated in IT networks, the potential relations change in case of error (earth fault of the
feeding mains supply) so that the rated voltage of 300 V against PE, which is important for the
design of insulation and network disconnection, is exceeded. This error must be detected.
–
Use of a diagnostic output for connection of a safety function.
The diagnostic outputs STA and SBA are not part of the safety circuit. The diagnostic outputs are
used to improve diagnostic coverage of the related safety function. The diagnostic outputs may
only be used in combination with the related safe control signals (AND link) and a reliable time
monitoring in the safety relay unit for switching additional safety-critical functions.
Foreseeable misuse of the safety function STO
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Use of the STO function without external measures for drive axles influenced by external torques.
If external torques influence the drive axle, the safetyfunction STO alone is not suitable to stop the
axle reliably. Additional measures are required to prevent dangerous movements of the drive axle,
such as use of a mechanical brake in combination with the safety function SBC.
–
Disconnection of the motor from the energy supply.
The safety function STO does not disconnect the drive from the power supply as defined by elec-
trical safety.
Safety
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Festo — CMMT-AS-...-S1 — 2018-02