7-10 Safety Function
7-10-1 Overview of Safety Function
To ensure safety, the 3G3MX2-EV2 Series Inverter has the STO (Safe Torque Off) function.
The STO function shuts off the power to the motor and stops the motor through the input signals from a
safety controller.
Precautions for Correct Use
Planning
•
Personnel who design, install, and maintain safety-related systems should have a thorough
knowledge of functional safety.
•
It is the responsibility of the user to introduce a safety-related system and implement a risk
analysis of the entire system, as well as to take appropriate measures as needed.
Design
•
The 3G3MX2-EV2 Series Inverter does not have a function to hold the STO status. This
means that the Inverter is ready for operation when STO input is reset and starts operation
when the RUN command is input.
•
Taking this into consideration, set up the system so that the Inverter does not cause danger-
ous situations when STO input is reset.
•
In the factory default settings, the STO function is disabled by a short-circuit wire.
Installation
•
Make sure that installation is carried out by a qualified electrician with a knowledge of func-
tional safety.
•
Use the 3G3MX2-EV2 Series Inverter within its environmental specifications, including
the EMS environment.
•
In order to prevent conductive dust and contamination, install it in an IP54 or higher panel.
Wiring
•
The Inverter does not have the function to diagnose STO input signals. Be sure that the sys-
tem is designed to provide two inputs normally. If necessary, use the EDM signal output to
perform fault diagnosis of the input paths.
•
Make sure that the two STO input signals from external devices are properly separated and
protected, where each signal is not subject to mutual interference.
•
Make sure that the cable length of the signal lines connected to the GS1, GS2, and EDM ter-
minals are 20 m or less for each.
Test Run
•
Be sure to perform a test run to verify and validate the safety system. No system can be con-
sidered “safe” before it is validated.
Maintenance
•
The STO function does not disconnect the Inverter from the main circuit and peripheral circuit
power supplies. Before you perform maintenance, be sure to isolate the system from the
main power system and from any devices including permanent magnet motors and capaci-
tors that may supply voltage to the system.
•
After you shut off the power supplies, wait at least 10 minutes, confirm that the charge LED is
OFF and that the voltage across the P and N terminals has dropped to 45 V or less, and then
perform maintenance.
•
Be sure to perform a periodic functional test once a year.
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