8.6 InstallationSafety relays that have a plus and minus switching output signal can be directly connected to the servo system to activate STO.The example in illustration 113 shows the basic connection to be made for the STO function. A suitable safety device to switch it off isnot supplied by Danfoss. The STO is activated by opening STO+ and STO–.Table 29: Activation of STO FunctionSTO+ STO– STO function24 V GND STO deactivatedOpen GND STO activated24 V Open STO activatedOpen Open STO activatedC A U T I O N- Do not exceed 30 V at the STO inputs.- STO is activated if the plus input is between –3 V and +3 V.- STO is deactivated if the plus input is between +21.6 V and +26.4 V.Illustration 113: Safety Relay with Plus and Minus Switching OutputSignals with test pulses must not have test pulses of >1 ms. Longer pulses may lead to reduced availability of the servo system.8.6.1 Protective Measures• Install the MSD 510 system components in a cabinet that is rated at least IP54 as per IEC 60529 or in an equivalent environment. Ahigher IP protection may be necessary for certain applications.• If external influences can affect the motor axis, for example suspended loads, use additional measures, such as a safety holdingbrake, to eliminate hazards.8.7 Application ExampleAn example of an application that can be put in Safe Torque Off mode by a safety circuit is shown in illustration 114.Select the safety switch devices in accordance with the requirements of the application.Functional Safety ConceptOperating Guide | VLT® Multiaxis Servo Drive MSD 510 SystemAQ262450196490en-000101 / 175R1170156 | Danfoss A/S © 2019.10
