Deploying I/O modules directly in harsh environments near machines in industrial automation sites can significantly reduce the size of control cabinets and wiring costs. The Beckhoff EP20xx/EP28xx series EtherCAT Box digital output module is an ideal choice for distributed I/O due to its high protection level of IP65/66/67, wide temperature operating range (-25~+60 ° C), and rich output current options (0.5A to 2.8A). However, when faced with a variety of models, the activation of diagnostic functions, safety behavior in the event of EtherCAT communication failure, and ATEX explosion-proof installation requirements, engineers often need a practical reference for the system. This article is based on official technical documents and presents a complete manual for model selection, mechanical installation, electrical wiring, TwinCAT configuration, and troubleshooting.
Product Series Overview and Selection Core
The EP20xx/EP28xx series includes multiple digital output modules, with the main differences being the number of output channels, single channel current, total current, connector type, and diagnostic function. When selecting, it is important to focus on the following dimensions:
Model Channel Number Single Channel Current Total Current Connector Diagnostic Function Special Instructions
EP2008-000x 8 0.5A 4A M8 (0001)/M12 (0002) Unbounded Type
EP2008-0022 8 0.5A 4A M12 (one per channel) without independent M12 socket
EP2028-000x 8 2.0A 4A M8 (0001)/M12 (0002) No high current output
EP2028-0032 8 2.8A 16A M12 (dual channel shared) without 7/8 "power connection, high total current
EP2038-000x 8 2.0A 4A M8 (0001)/M12 (0002) Short circuit/broken wire diagnostic type
EP2038-0042 8 2.4A 16A M12 (one per channel) Short circuit/disconnection/undervoltage M12 D-coded EtherCAT, 7/8 "power supply
EP2809-002x 16 0.5A 4A M8 (0021)/M12 (0022) without high-density 16 channels
EP2809-0042 16 0.5A 16A M12 (2 channels per socket) without high density, 7/8 "power supply
EP2816-0003 16 0.5A 4A ZS2001 Spring Terminal Short Circuit Detection IP20 Connector (Limited Protection Level)
EP2816-0004 16 0.5A 4A M16 19 pin short circuit detection IP67
EP2816-0008 16 0.5A 4A D-sub 25 pin short circuit detection IP67
EP2816-0010 16 0.5A 4A 2 × D-sub 9-pin short circuit detection IP67
EP2817-0008 24 0.5A 4A D-sub 25 pin short circuit/undervoltage 24 channel high-density
EP2839-0022 16 0.5A 4A M12 (2 channels per socket) Short circuit/disconnection/undervoltage M8 EtherCAT, diagnostic type
EP2839-0042 16 0.5A 16A M12 (2 channels per socket) Short circuit/disconnection/undervoltage M12 D-coded EtherCAT, 7/8 "power supply
Selection decision:
If diagnosis (short circuit, wire breakage detection) is required, priority should be given to the EP2038 and EP2839 series.
If driving high current loads (such as valve islands), choose EP2028-0032 (2.8A/channel) or EP2038-0042 (2.4A/channel).
If you need high channel density (16/24 channels), choose the EP2809, EP2816, EP2817, EP2839 series.
If compatibility with existing D-sub connector harnesses is required, choose EP2816-0008 or EP2817-0008.

Key points for mechanical installation and IP67 protection
2.1 Installation dimensions and fixation
Narrow body modules (30mm wide, such as EP2008, EP2028, EP2038, EP2816, EP2817) are fixed with two M3 bolts (mounting holes Ø 3.5mm).
The wide body module (60mm wide, such as EP2809, EP2028-0032, EP2038-0042, EP2839) is fixed with two M4 bolts (mounting holes Ø 4.5mm).
The bolt length should be greater than 15mm, and the installation hole should be non threaded. It should be matched with a nut or directly screwed into the threaded hole of the chassis.
It is recommended to use Beckhoff mounting rail ZS5300-0001 (stainless steel, preset M3 thread) to quickly install multiple modules.
2.2 Functional Grounding (FE)
For wide body modules (EPxxxx-002x, -0042), the fixing screws also serve as functional grounding (FE) connection points. Low impedance grounding connection must be used, such as installing the module on a grounded metal machine tool. Ensure that both screws are reliably grounded, otherwise it may affect EMC performance.
2.3 Implementation of IP67 protection
Key precautions:
All interfaces are pre installed with protective covers at the factory, but these covers are only for transportation protection and may not have been tightened. Before installation, it is necessary to confirm that all protective covers or cable connectors have been tightened to the specified torque (M8: 0.4Nm, M12: 0.6Nm, 7/8 ": 1.5Nm).
Unused interfaces must be sealed with suitable protective covers (ZS5000 series can be ordered).
IP67 protection level is only guaranteed when all interfaces are properly sealed.
2.4 ATEX explosion-proof installation (applicable to modules with ATEX certification)
For ATEX certified models such as EP2008 and EP2028, an additional protective cover BG2000-0000 or BG2000-0010 is required, and the ambient temperature is limited to 0-55 ° C (-25~+60 ° C for non ATEX). During installation, the cable needs to pass through the protective cover opening, and all interfaces of the module must be sealed. The protective cover itself also needs to be fixed. The transient overvoltage of the power supply voltage during use in explosion-proof areas shall not exceed 40% of the rated voltage.