Invertek Drives elevator CORE Quick Start-Up Manual page 51

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19.1.7.
The "STO" wiring shall be protected from inadvertent short circuits or tampering which could lead to failure of the "STO" input
signal, further guidance is given in the diagrams below.
In addition to the wiring guidelines for the "STO" circuit below, section 8.2 "EMC compliant installation" should also be followed.
The drive should be wired as illustrated below; the 24Vdc signal source applied to the "STO 1 and STO 2" inputs can be either from the 24Vdc
on the drive or from an External 24Vdc power supply (as per the diagram below).
19.1.8. Recommended "STO" wiring
Note: The Maximum cable length from Voltage source to the drive terminals should not exceed 25 metres.
19.1.9. External Power supply Specification.
Voltage Rating (Nominal)
STO Logic High
Current Consumption (Maximum)
19.1.10. Safety Relay Specification.
The safety relay should be chosen so that at minimum it meets the safety standards in which the drive meets.
Standard Requirements
Number of Output Contacts
Switching Voltage Rating
Switching Current
"STO"Electrical Installation
24Vdc
18-30Vdc (Safe torque off in standby)
100mA
SIL3 or PLe or better (With Forcibly guided Contacts)
2 independent
30Vdc
100mA
Using External 24Vdc power Supply
Using Drive on-board 24Vdc power Supply
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