STO signal for group disconnection

For group drives, the STO signal may be provided for several devices by a single safety relay. The following requirements must be met:

• The total cable length is limited to max. 100 m. 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 maximum permitted contact load of the safety device must be observed (see the product manual, chapter "Technical data" > Electronic data – Safety sub-function).
• 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 cable routing requirements apply.
• A calculation based on the technical data of the device must be performed separately for each case of group drive disconnection.
• A maximum of 20 devices may be used in a group disconnection.