BECKHOFF EL9xxx System Terminal Guide

EL9550-0010 system+on-site, with currents of up to 10 A each (total 10 A) and 4 bits (Up/Us undervoltage/overvoltage), suitable for high current devices such as CX embedded PCs

EL9550-0012 system+on-site, each with 10 A independently, no higher capacity

Diagnostic application: EL9540-0010 provides "Undervoltage" and "Overvoltage" bits (1 bit each) in the process image. EL9550-0010 provides 4 digits (Up Undervoltage, Up Overvoltage, Us Undervoltage, Us Overvoltage). When the voltage is below 18V or above 30V, the corresponding bit becomes TRUE. By utilizing this information, it is possible to safely shut down the output or record events in the event of abnormal voltage.

Installation location: The surge filter should be placed as close as possible to the power inlet. The manual provides application examples: EL9550 supplies power to couplers and digital terminals, and EL9540 supplies power to analog terminals, forming a two-layer protection.

Buffer capacitor terminal: EL9570

The EL9570 has a built-in 500 µ F capacitor with an internal resistance of<10 µ m Ω, which is used to smooth power supply voltage fluctuations and absorb regenerative energy. Typical applications include parallel connection with stepper motor terminals (EL7041), DC motor terminals (EL7342), or servo motor terminals (EL7201). When the motor decelerates, the regenerated energy will increase the DC bus voltage, and EL9570 absorbs this energy; If the voltage exceeds 55   V, the internal circuit will connect to an external braking resistor (recommended 10   Ω/10   W) to consume excess energy. The overload LED (green) stays on when energy is absorbed by the resistor.

Attention: The rated voltage of EL9570 is 50   V and cannot be used for 230   V systems. Its power contacts on both sides are straight through, but there is no PE contact on the left side. Multiple motors can share one EL9570, but the total regenerative energy needs to be calculated.

Interference free terminals in secure applications

In TwinSAFE safety applications, certain standard terminals are classified as' interference free ', meaning they do not affect the safety integration level (SIL/PL). But when using, it must meet the hardware version requirements (see tables on pages 15-16 of the manual, such as EL2004 starting from hardware version 15, EL2809 starting from 01, etc.). In addition, external wiring must eliminate short circuit faults, including:

Use independent sheathed cables (different potentials do not share the same sheath)

Only wiring within the same control cabinet

Each wire has independent grounding protection

Permanent fixation of cables and prevention of external damage

If the "ground feedback+full pole cut-off" measures are used, the maximum can reach Cat.4/PL-e/SIL-3.

Key: In a potential group, all terminals must be interference free, and external circuits cannot provide energy feedback even under fault conditions.

Rules for placing passive terminals

The so-called passive terminal refers to terminals that do not participate in active data exchange and do not consume E-bus current, such as EL9011 (end cover), EL9080 (potential separation), EL9070 (shielding), EL9180 and other potential distribution terminals, EL9400/9410 (E-bus feeding), and EL9540/9550 (surge filter). To ensure the integrity of the E-bus signal, no more than two passive terminals should be connected in series. If more passive terminals must be connected after two passive terminals, an active terminal (such as EL1004 digital input) should be inserted in the middle. Otherwise, it may cause data delay or errors.

Installation and wiring specifications

10.1 DIN rail installation

All EL9xxx terminals are installed on a 35 mm guide rail (EN 60715). The steps are as follows:

First, hang the coupler (such as EK1100) onto the guide rail.

Push the terminal into the slot from the right side until the locking buckle clicks into place. It is strictly prohibited to first clamp the guide rail and then push it laterally, otherwise it will damage the power contacts and E-bus spring.

When disassembling, pull the orange buckle strap by about 1cm to release the buckle, and then pull out the terminal.

10.2 Enhance mechanical load capacity

For applications with severe vibration (such as ships and vehicles), TH35-15 guide rails should be used, with mechanical fasteners clamped at both ends. The total number of terminals should not exceed 64 (12mm width) or 32 (24mm width), and the distance between guide rail fixing points should be ≤ 5cm. Terminals such as EL9100, EL918x, EL9400, etc. all support reinforced mechanical loads.

10.3 Wiring Techniques

Standard spring terminal (ELxxxx): Insert a screwdriver vertically into the square hole, press in the wire, and then remove the screwdriver. The cross-sectional area of the wire is 0.08... 2.5 mm ², and the stripping length is 8-9 mm.

HD terminals (EL9181/2/3/4/8/9): Solid wires can be directly inserted into circular holes without the need for tools; The fine twisted wire needs to be pressed with a screwdriver. The stripping length is 8-9mm.

Shielded connection: The shielded terminals of EL9070 and EL9195 are directly pressed into the bare wire of the shielding layer, and the other end is connected to the guide rail.