Overview Of Sto Function; Logic Table For Sto Function; Description Of Sto Channel Delay - INVT Goodrive20-EU VFD Series Operation Manual

Goodrive20-EU series VFD

3.3 Overview of STO function

Reference standards: IEC 61508-1, IEC 61508-2, IEC 61508-3, IEC 61508-4, IEC 62061, ISO
13849-1, IEC 61800-5-2.
The STO function can be used where main power of the drive is on to prevent unexpected
start. The function cuts off the drive signal to disable the drive output, thus preventing motor
from unexpected start (refer to below figure). After enabling STO function, short-time
operations (like non-electrical cleaning-up in lathe industry) and/or maintenance on
non-electrical parts can be conducted.
Control
circuit

3.3.1 Logic table for STO function

Input states and corresponding faults of STO function:
STO input state
H1, H2 opens simultaneously Trigger STO function, the drive can't operate normally
H1, H2 closes simultaneously Don't trigger STO function, the drive can operate normally
Either H1 or H2 opens or
closes

3.3.2 Description of STO channel delay

STO channel trigger and indication delay time:
STO mode
STO fault: STL1
+24V
H1
H2
COM
UDC+
PWM+
U/V/W
Drive
circuit
PWM-
UDC-
Figure 3-15 STO function schematic
Trigger STL1/STL2/STL3 fault, fault code:
38: Safety circuit of channel 1 is abnormal (STL1)
39: Safety circuit of channel 2 is abnormal (STL2)
40: Internal circuit is abnormal (STL3)
STO trigger and indication delay
Trigger delay＜10ms, Indication delay＜280ms
23
Switch, relay, etc.
Note: The contact of safety switch must be
opened/closed within 250ms; the cable between the
VFD and safety switch should be no longer than
25m.
Corresponding STO fault
Installation guide
1), 2)