Functions 
  5.5 Functions of the inputs 
SIRIUS 3RW30 / 3RW40 
Manual, 10/2018, NEB535199502000/RS-AB/005 
53 
 
Start input (terminal 3) on 3RW405 and 3RW407 
Rated control voltage is present at terminal A1 / A2: The startup process of the soft starter 
begins when a signal is present at terminal 3 (IN). The starter operates until the signal is 
removed again. If a ramp-down time is parameterized, a soft stop starts as soon as the 
signal is removed. 
The 24 V DC control voltage supplied by the soft starter must be taken from terminal 1 (+) as 
voltage for the signal at terminal 3. 
If you select direct control by a PLC, the "M" of the PLC's reference potential must be 
connected to terminal 2 (-). 
 
For recommended circuits, e.g. control by means of pushbuttons, contactor contacts, or a 
PLC, refer to chapter Typical circuit diagrams (Page 161). 
 
Thermistor input / connection on 3RW402 to 3RW404 
24 V AC/DC rated control voltage 
After removing the copper jumper between T11/21 and T22, you can connect and evaluate 
either a Klixon thermistor integrated in the motor winding (at terminal T11/T21-T22) or a type 
A PTC (at terminal T11/T21-T12).