Siemens EN 50295 manual AS-Interface Safety at work, Introduction, Safety included, Tested safety

AS-Interface

AS-Interface Safety at work

Introduction

■Overview

Standard PLC Standard master

Security monitor

Standard slave Power section

Secure slave

with EMERGENCY-OFF

Signal evaluation of secure slave/security monitor Master information (through regular I/O transfer)

G_IK10_XX_20021

Safety included

The Safety at Work concept supports the direct integration of

6switches, protective cover switches or safety light barriers, in the AS-Interface network. These are fully compatible with the familiar AS-Interface components (masters, slaves, power supply units, repeaters, etc.) in accordance with EN 50295 and are operated in conjunction with them on the yellow AS-i cable.

The signals from the safety sensors are evaluated by a safety monitor. This not only monitors the switching signals of the safety sensors but also continuously checks that data is being trans- ferred correctly. The safety monitor has one or two release cir- cuits in a two-channel configuration which can be used to bring the machine or installation into a safe state. Sensors and moni- tors can be connected at any point on the AS-Interface network. It is also possible to use several monitors in the same network.

A failsafe controller or a special master is not necessary. The master handles safety slaves in the same manner as all other slaves and only receives the safety data for information pur- poses. They can therefore be used to expand any existing AS-Interface network.

Safety at Work guarantees a maximum response time of 40 ms. This is the time between application of the signal to the input of the safe slave and switching off the output at the safety monitor.

Tested safety

The system has been tested and approved by the German Technical Inspectorate (TÜV). The transmission technique for signals with relevance for safety is designed to allow applica- tions to be implemented up to category 4 in accordance with EN 954-1.

Software

The safety-related applications can be configured using the configuration software and then transferred into the monitor. Moreover, the software can also be used for online diagnostics.

■Benefits

•A failsafe PLC or special master is not required.

•Simple system structure due to standardized AS-Interface technique.

•Safe and non-safe data on the same bus.

•Existing systems can be expanded quickly and easily.

•Safe signals can be combined in groups.components with relevance for safety, such as emergency stop

•Integration of the safety signals in the plant diagnostics con- cept.

•Approved up to category 4 acc. to EN 954-1.

•Safety at Work is certified by the German Technical Inspec- torate (TÜV).

■Application

Integrated safety systems using AS-Interface can be used in ap- plications for which EMERGENCY-STOP pushbuttons, protective door locks, Stop category 0 and 1, two-handed operation and light arrays are currently installed.

■Design

The safety system is constructed in the same manner as the now familiar installation of AS-Interface.

The family of safe AS-Interface products comprises the safety monitor that monitors the safe stations. The spectrum of safe sta- tions comprises the safe modules and the safety-related sensors with an integrated interface.

■Function

Following a master call, the safe stations transmit their informa- tion, like the standard stations, to the master. The safety monitor monitors this transfer from the safe stations to the master and switches

•to the EMERGENCY-STOP status (in the case of faults in safe stations) or

•to the safe status (in the case of a wire break).

The safety monitor is configured using software. The configura- tion comprises the input signals of the safe stations and the in- ternal functions of the safety monitor. The safety monitor offers OR logic, AND logic, timer functions, buffer storage, etc.

■Integration

For integration of the safety system into AS-Interface, the exist- ing infrastructure such as the master and the power supply unit can continue to be used. For the safety system, the safety mon- itor is integrated as a monitoring component and the safe station is integrated as the interface between the safe sensors and the system. The safe sensors can be used as before.

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Siemens IK PI · 2004