Complete Guide to Inline Automation Terminal System

UL (7.5V DC): Communication power supply, providing power to the microcontroller and bus interface inside the terminal. Converted from 24V input by a bus coupler or specific power terminal.

UANA (24V DC): Analog voltage, supplying power to analog input/output terminals.

UM (24V DC): The main circuit power supply provides the main power for digital I/O, usually from an external power source.

US (24V DC): Segmented circuit power supply, which can be disconnected from UM through jumpers or fuses, used to create multiple load segments that can be independently protected or turned off.

GND: The common reference ground for the main circuit and segmented circuit.

FE: Functional grounding, used to improve the system's anti-interference ability.

2. Circuit segmentation and electrical isolation

By using different types of power terminals and segmented terminals, multiple electrically isolated areas can be created within a physical station. For example:

A power terminal can interrupt all incoming potential jumpers and inject new power. This allows the creation of areas with different voltages such as 24V DC and 230V AC on the same DIN rail, and achieves electrical isolation between them.

A segmented terminal only interrupts the US (segmented circuit) jumper. This allows engineers to set fuses or switches for multiple load groups under a main circuit, achieving refined power management. For example, a short circuit fault in an output module will only cause the fuse of the segment circuit it is in to actuate, without affecting other I/O modules and bus communication within the same station.

Hardware Structure and Connection Technology

1. Basic structure of terminal

Each Inline terminal is mainly composed of two parts: an electronic module base and a pluggable connector.

Electronic module base: includes all electronic components of the terminal and lateral blade contacts for potential and data routing. On the left side of the base, there is a "raised" pin arrangement, and on the right side, there is a corresponding "groove". When the terminals are installed side by side, the left pin will be precisely inserted into the groove of the adjacent terminal on the right, thereby establishing mechanical and electrical connections.

Pluggable connector: used to connect field devices (sensors/actuators) and power supply. This separated design allows for quick replacement of faulty electronic modules without dismantling any on-site wiring, greatly reducing maintenance downtime.

2. Spring connection technology

The connectors of Inline terminals commonly use spring wiring technology. This technology has advantages such as anti vibration, reliable connection, and fast operation. When wiring, simply use a screwdriver to press open the spring, insert the stripped cable, and after pulling out the screwdriver, the spring will automatically press the wire. The cross-sectional area of the connectable wires is usually 0.08 mm ² to 1.5 mm ².

3. Shielded connection

For sensitive signals such as analog signals and encoder signals that are susceptible to interference, shielded cables must be used. The Inline system provides specialized shielded connectors (such as IB IL SCN-6 SHIELD). The connector has a shielding clamping device inside, which can firmly clamp the braided shielding layer of the cable and connect it to the functional grounding (FE) potential, effectively suppressing external electromagnetic interference.

Installation and Engineering Practice Guide

Successful system design is not only about selecting the right modules, but also about following a series of engineering best practices.

1. Installation distance and heat dissipation

To ensure long-term stable operation of the system, sufficient heat dissipation space must be ensured.

For standard I/O terminals, at least 35mm-50mm of space needs to be left above and below for heat dissipation and wiring.

For power level terminals such as motor starters, due to significant power loss, the vertical installation distance requirements are more stringent to ensure free air circulation and prevent overheating.

2. Grounding and equipotential connection

Correct grounding is the cornerstone of system anti-interference and safe operation.

Functional Grounding (FE): All 24V DC terminals are connected to the galvanized DIN rail via a metal spring at the bottom. For bus couplers and power terminals, it is strongly recommended to use an additional wire to connect their FE terminals to the central grounding busbar to ensure reliable grounding even in the event of DIN rail surface oxidation or poor contact.

Protective Grounding (PE): For 120V/230V AC and 400V AC areas, their power terminals and power terminals must be reliably grounded through dedicated PE terminals. This is an important measure to ensure personal safety.

3. Terminal sorting principle

In a main circuit, the arrangement order of terminals should consider the current load and signal type.

High current priority: The digital output terminal with the highest current consumption should be placed near the power terminal. This can avoid high current flowing through the potential jumper of the entire station for a long time, thereby reducing line losses and heating.