This Safe Stop 1 (SS1) implementation causes the drive to come to rest in a controlled manner, and STO is actioned after a time delay determined by
the safety delay relay. This conforms to SS1 defined in EN61800-5-2:2007 para 4.2.2.3 c). The example shows wiring and terminal numbering for a
Siemens 3TK2827, but similar products are available from other vendors. Use of this Siemens part does not imply it is suitable for the user's application.
The user must select and assess appropriate equipment.
SAFETY
DEMAND
POWER
A1
SUPPLY
SAFETY CONTROL UNIT
A2
Note: On power-up, the Safety Control Unit outputs are OPEN; thus STO is requested of the inverter. This responds by energising KA1 if both channels
are active and healthy. KA1 is used as a self-check for the reset cycle of the Safety Control Unit. If a reset cannot be achieved due to KA1 being de-
energised, a fault may be present and must be resolved by the user before relying on the STO function. See Fault Operation on page 8-13.
To start the drive:
Ensure the Safety Demand switch is reset (contacts closed). Press the RESET button to ensure the Safety Control Unit is reset; its
contacts to the inverter should close making the STO function inactive. The inverter STO output should then turn OFF. Then press the