BECKHOFF CU20xx/CU22xx Switch Installation and Troubleshooting

Beckhoff CU20xx/CU22xx Industrial Ethernet Switch Installation, Debugging, and Troubleshooting Guide

In industrial automation networks, Ethernet switches serve as the core nodes for data aggregation and forwarding, and their reliability and performance directly affect the communication stability of the entire system. The Beckhoff CU20xx series (5/8/16 port 100Mbps) and CU22xx series (8-port Gigabit) industrial Ethernet switches are ideal choices for network cabling inside control cabinets due to their compact metal casing, unmanaged plug and play design, automatic cross detection, and wide temperature capability. However, in the face of practical issues such as lack of support for PoE, limitations on macro frame usage, UL power supply standards, and on-site LED diagnostic interpretation, engineers need a clear practical guide. This article is based on official technical documents and presents a systematic engineering practice manual for you, covering model selection, mechanical installation, electrical wiring, functional principles, and troubleshooting.

Product Series Overview and Selection Points

The CU20xx/CU22xx series includes four models, all of which are installed on DIN rails, powered by spring terminals (24V DC), and support adaptive speed and full/half duplex modes:

Model, Port Number, Rate, Typical Current Size (W × H × D), Giant Frame Support

CU2005 5 10/100 Mbit/s 90 mA 73 × 100 × 38 mm No

CU2008 8 10/100 Mbit/s 100 mA 85 × 100 × 38 mm No

CU2016 16 10/100 Mbit/s 150 mA 146.5 × 100 × 38 mm No

CU2208 8 8 10/100/1000 Mbit/s 180 mA 122 × 100 × 38 mm is (≤ 9720 bytes)

Selection decision:

If the network needs to transmit a large amount of video or high-throughput data, choose CU2208 Gigabit Switch, but its macro frame function is only effective on Gigabit link ports, and it supports up to 2 ports using macro frames at full load.

All models do not support PoE (IEEE 802.3), and it is strictly prohibited to connect PSE devices, otherwise it may cause damage.

The ambient temperature range is 0-55 ° C, storage is -25~85 ° C, humidity is 95% without condensation, meeting the basic requirements of industrial sites.

Mechanical installation: DIN rail fixation and space reservation

The CU series switch adopts standard 35mm DIN rail installation (compliant with EN 50022), and installation and disassembly do not require tools:

Installation steps:

Fix the installation guide rail in the designated position of the control cabinet.

Hang the lower side card spring of the switch onto the lower edge of the guide rail.

Push the switch (1) upwards while pressing the upper side (2) towards the guide rail until you hear the locking sound.

Connect the cable.

Disassembly steps:

Remove all cables.

Push the switch (3) upwards to disengage the lower side.

Pull the upper side (4) away from the guide rail and remove the switch.

Space requirements:

The depth varies depending on the RJ45 connector model, and it is recommended to reserve sufficient space for plugging and unplugging.

An additional height of approximately 10mm is required above the guide rail to facilitate the locking action.

The width of each model is shown in the table above. When multiple units are installed side by side, the heat dissipation gap (at least 20mm) should be considered.

Electrical wiring and power requirements

3.1 Power supply terminal (spring type three pin)

Terminal definition:+(24V DC positive), - (0V), PE (protective grounding).

Voltage range: 18~30V DC, with polarity reversal protection.

Current consumption: CU2005 about 90mA, CU2008 about 100mA, CU2016 about 150mA, CU2208 about 180mA.

3.2 UL compliant power supply (key)

According to UL certification requirements (cULus), switches must be powered by one of the following methods:

Isolation power supply, with a maximum 4A fuse connected in series at the front end (compliant with UL248); or

NEC Class 2 power supply (output limited).

It is strictly prohibited to use two NEC Class 2 power supplies in series or parallel.

In addition, the device must not be connected to an unrestricted voltage source, otherwise it does not comply with UL safety regulations.

3.3 Ethernet wiring

The RJ45 interface supports automatic cross detection (Auto MDI/MDIX), which can be connected directly or across Ethernet cables.

The maximum length of twisted pair cables is 100 meters, and switches can be cascaded without restrictions (but attention should be paid to total latency and broadcast storm risks).

The pin definition follows the standard EIA/TIA 568B (1, 2 send, 3, 6 receive).

LED status diagnosis

Each RJ45 port is equipped with two LEDs, providing real-time link and activity status:

Meaning of LED status

Link/ACT (green/yellow) is off and there is no connection

Constant light link established (Link)

Flashing Data Transmission (Activity)

100/1000 (orange/green) extinguishes 10 Mbit/s connection

Constant brightness (CU2005/08/16) 100 Mbit/s connection

Constant brightness (CU2208) 1000 Mbit/s connection

Power LED (green): Constant light indicates normal 24V power supply.

Quick fault location:

If the Link light on a certain port does not light up: check if the network cable is disconnected, if the other end device is powered on, and if the port is disabled (no disabled function for unmanaged switches, which can generally be ruled out).