The EL1904 TwinSAFE component is a digital input terminal for sensors with potential-free contacts for 24 V DC. It has four fail-safe inputs. The signals are transmitted via FSoE to a TwinSAFE Logic-capable component and can be used there to evaluate them in terms of safety.

TwinSAFE 端子模块 EL1904 是一个数字量输入端子模块，适用于具有无源触点的 24 V DC 传感器。 它有 4 个安全输入。 信号通过 FSoE 传输至 TwinSAFE 安全逻辑模块，并可在该模块上评估信号的安全性。

EL1904 Version: 3.3.19 1.6 Safety and instruction Read the contents that refer to the activities you have to perform with the product. Always read the chapter For your safety [} 12] in the operating instructions. Observe the warnings in the chapters so that you can handle and work with the product as intended and safely. Explanation of symbols

a：需要将新的el1904 和el2904 的侧面安全拨码设置为和原先旧的模块完全一样，并且安 装在同样位置即可。 不需要重新下载安全程序

EL2904 上面的诊断灯都表示什么？ 说明书下载链接： https://download.beckhoff.com/download/document/automation/twinsafe/el2904_en.pdf. 如果Diag 2指示灯闪5下，可以尝试将模块两路供电的上电时间间隔开，先供应++/--这路，再供24V/0V这路。 2018.12.27 徐樱樱 编辑.

View and Download Beckhoff EL1904 operating instructions manual online. TwinSAFE Terminal with 4 digital fail-safe inputs. EL1904 touch terminals pdf manual download.

EL1904. 可以，模块下方有input channel，可以类似el1004用法，直接做Linkto即可。

EL1904 DIN Rail MOUNTING, 24 VDC, 4-Channel Digital Input, Cross-Circuit Detection, TWINSAFE, ETHERCAT Terminal, IP20

EL1904 Version: 2.1.19 2 System description 2.1The Beckhoff Bus Terminal system The Beckhoff Bus Terminal system is used for decentralized connection of sensors and actuators to a control system. The Beckhoff Bus Terminal system components are mainly used in industrial automation and building management applications.

Product No. : EL1904. Product Type : EtherCAT Terminal, 4-channel digital input, 24 V DC, TwinSAFE. Connection technology : 1-/2-wire. Number of inputs : 4. Protocol : TwinSAFE/Safety over EtherCAT. Response time : typ. 4 ms (read input/write to E-bus) Fault response time : ≤ watchdog time (parameterizable) Current consumption E-bus : typ. 200 mA