Functions; Specification Of Safety Functions; Performance Level (Pl) And Safety Integrity Level (Sil); Validation Of Performance Level - Danfoss VLT Safety Option MCB 150 Installation Manual

Installation Guide | VLT® Safety Option MCB 150/151
Detect
Sensor
For example lightcurtain
Illustration 3: Sensor-Logic-Actuator Safety Chain

3.2 Functions

3.2.1 Specification of Safety Functions

The standards require a specification of functional requirements. The specification must contain details about each safety function that
should be executed. Also define the:
• Necessary interfaces with other control functions.
• Required error responses.
• Performance level required PLr or achievable SIL level.

3.2.1.1 Performance Level (PL) and Safety Integrity Level (SIL)

For safety-related control systems, Performance Level (PL), according to EN ISO 13849-1, and SIL levels, according to EN IEC 61508 and
EN IEC 62061, include a rating of the system's ability to perform its safety functions.
All the safety-related components of the control system must be included in both a risk assessment and the determination of the
achieved levels. Refer to EN ISO 13849-1, EN IEC 61508, or EN IEC 62061 standards for complete information on requirements for PL and
SIL determination.

3.2.2 Validation of Performance Level

Check whether the required Performance Level "PLr", determined in the risk assessment, is achieved by the selected system for each
safety function used. Check the calculation using the SISTEMA SW Tool of IFA (Institute for Occupational Safety & Health). Danfoss
provides a component library which can be used for the calculation. Danfoss offers corresponding services to support the system
check by calculation. Library can be downloaded from www.dguv.de/ifa/en/pra/softwa/sistema.
If using another validation method for the performance level, use the characteristic safety values specified.

3.2.3 Activation of Safety Functions

• The safety functions are activated using the dual-pole safe inputs on the safety option.
• These inputs operate in accordance with the fail-safe principle (on switching off). The safety control system activates the safety
functions via a 1/0 transition.
• Deactivate the safety functions before applying any changes to them.
Danfoss A/S © 2018.09
Process
Logic
For example MCB 15x
Functions and Systems Overview
Switch
Actuator
For example FC 302
AQ279747441421en-000101 / 130R0292 | 15