Switching off the STO signal for several drive units (STO group disconnection)

The STO signal for several drive units can be provided by a single safety relay. The following requirements must be met:

• The total cable length is limited to max. 100 m. Any other instructions published by the manufacturer on the use of the safety device (for the respective application) must also be observed.
• The maximum output current and the maximally permitted contact load of the safety device must be observed.
• You must comply with the permitted signal levels at the STO input and all other technical data of the device. The routing of the STO control cables and the voltage drop must be considered.
• Other requirements of the safety manufacturer (such as protecting the output contacts against welding) must be strictly observed. The basic requirements for cable routing also apply.
• A calculation based on the technical data of the device must be performed separately for each case of STO group disconnection.

• A maximum of 20 drive units may be used in one STO group disconnection.