BECKHOFF EL1904 - Manual (Page 3)

Table of contents
EL1904 1
Table of contents
1 Foreword 3
1.1 Notes on the manual 3
1.1.1 Disclaimer 3
1.1.2 Brands 3
1.1.3 Patents 3
1.1.4 Copyright 3
1.1.5 Delivery conditions 3
1.2 Safety instructions 4
1.2.1 Delivery state 4
1.2.2 Operator's obligation to exercise diligence 4
1.2.3 Description of safety symbols 5
1.2.4 Origin of the document 5
1.2.5 Documentation issue status 6
2 System description 7
2.1 The Beckhoff Bus Terminal system 7
2.1.1 Bus Coupler 8
2.1.2 Bus Terminals 9
2.1.3 E-bus 9
2.1.4 Power contacts 9
2.2 TwinSAFE 10
2.2.1 The I/O construction kit is extended safely 10
2.2.2 Safety concept 10
2.2.3 EL1904, EL2904 – Bus Terminals with 4 fail-safe inputs or outputs 11
2.2.4 EL6900 - TwinSAFE logic terminal 11
2.2.5 The fail-safe principle (Fail Stop) 11
3 Product description 12
3.1 General description 12
3.2 Intended use 13
3.3 Technical data 14
3.4 Safety parameters 15
3.5 Characteristic curve of the inputs 15
3.6 Dimensions 16
3.7 Block diagram EL1904 17