Commissioning; Activating Sto; Automatic/Manual Restart Behavior; Automatic Restart Behavior - Danfoss VLT AutomationDrive EZ FC 321 Operating Manual

Safe Torque Off
Operating Guide

4 Commissioning

4.1 Safety Instructions
ELECTRICAL HAZARD
The operator or electrical installer is responsible for proper grounding and compliance with all applicable national and local safe-
ty regulations.
See 2.5 Safety Precautions and the Operating Guide of the relevant drive. Also, always observe the instructions provided by the
motor manufacturer.

4.2 Activating STO

The STO function can be used for asynchronous, synchronous, and permanent magnet motors.
Ensure that external safety devices fulfill Cat./PL or SIL when connected to terminal 37.
Procedure
1. Remove the voltage at terminal 37 of the drive.
2. Connect the drive to an external safety device providing a safe delay.

An installation for a Safe Stop 1 can be obtained.
When the STO function (terminal 37) is activated, the drive issues an alarm, trips the unit, and coasts the motor to a stop. Manual
restart is required. Use the STO function to stop the drive in emergency stop situations. In normal operating mode when STO is not
required, use the standard stop function instead. Ensure that requirements according to ISO 12100 paragraph 6.3.3.2.5 are fulfilled
before using the automatic restart function.

4.3 Automatic/Manual Restart Behavior

The STO default state prevents unintended restarts (restart prevention behavior). To terminate STO and resume normal operation,
follow the procedure below.
Procedure
1. Reapply 24 V DC to terminal 37.
2.
Give a reset signal via bus, digital I/O, or [Reset] key.
Set the STO function to automatic restart by setting the value of parameter 5-19 Terminal 37 Safe Stop from default value
[1] Safe Stop Alarm to value [3] Safe Stop Warning.
Automatic restart means that STO is terminated and normal operation is resumed when the 24 V DC is applied to terminal
37. No reset signal is required.

4.4 Automatic Restart Behavior

Automatic restart means that STO is terminated and normal operation is resumed when the 24 V DC is applied to terminal 37. No
reset signal is required.
Procedure
1.
Set parameter 5-19 Terminal 37 Safe Stop to [3] Safe Stop Warning.

4.5 STO Commissioning Test

A successful commissioning test of the STO function is required after the initial installation and after each subsequent change to
the installation or application involving the STO.
• For applications without automatic restart after a safe stop, follow the instructions in
tion.
• For applications with automatic restart after a safe stop, follow the instructions in
Danfoss A/S © 2022.11
C A U T I O N
N O T I C E
4.5.1 Restart Prevention for STO Applica-
4.5.2 Automatic Restart of STO
AQ355238304444en-US0301 / 130R0955 | 11
Commissioning
Application.