Sto Function Activation And Indication Delays; Installation - ABB ACS355 User Manual

402 Appendix: Safe torque off (STO)

STO function activation and indication delays

STO activation delay is below 1 ms. STO indication delay (time from the de-
energization of any STO input to the updating of the status bit) is 200 ms.
Note: If any STO channel is toggled very fast, it is possible that the drive trips to
overcurrent or short circuit.

Installation

Connect the cables as shown in the diagram below.
ACS355
X1C: OUT1
X1C: OUT2
X1C:3 IN1
X1C:4 IN2
STO input channels can be also supplied with an external power supply. The required
supply current is maximum 15 mA for each STO channel, and the voltage
requirement is 24 V DC +/-10%. The negative terminal of the power supply must be
connected to the analog ground (AGND) of the drive.
ACS355
AGND
X1C:1 OUT1
X1C:2 OUT2
X1C:3 IN1
X1C:4 IN2
STO can also be daisy-chained from drive to drive, so that several drives are behind
one safety switch. If STO outputs (OUT1 and OUT2) are used to supply the STO
circuit, maximum five drives can be supplied. The number of drives depends on the
13 23 31
14 24 32
+24 V DC external
power supply
-
+
13 23 31
14 24 32
Y1 Y2
Safety relay
A1 A2
Y1 Y2
Safety relay
A1 A2
Safe PLC
OUT
GND
Safe PLC
OUT
GND