Operating and application notes for SFP modules with the CU1521-0020

Fig.8: CU1521-0020, rotary switch positions and ports

Function range

• FW01: only use in pairs possible, with identical SFP on both sides
• FW02 and higher: single use also possible, e.g. vs. EK1501 with corresponding SFP

EtherCAT mode

• All 3 ports X1, X2, X3 are in operation in the order designated by rotary switch
• The CU1521-0020 can be used as a 2-port media converter or as a 3-port branch with media converter function
• The ports X1/X2 can be equipped with different SFP, at least one is necessary (see following SFP note)
• 100Mbit EtherCAT is supported (as of 2023), Gbit EtherCAT is in preparation (nevertheless 1Gbit-SFP are needed!)
• Only SFP modules approved by Beckhoff should be used to ensure EtherCAT suitability.
  The following types have been qualified by Beckhoff (status 2025-05):
• SingleMode
  • Optomedia PT1-S1-4203L
• MultiMode
  • Optomedia PT1-M4-4023L
• Bidirectional
  • Cisco GLC-BX40-D-I and GLC-BX40-U-I, Bidirectional optical fiber, LC/PC, 40km, 1550/1310nm
  • FS 36888 1000BASE-BX-D BiDi SFP 1550nm-TX/1310nm-RX 40km LC/PC (2024)
  • FS 36889 1000BASE-BX-U BiDi SFP 1310nm-TX/1550nm-RX 40km LC (2024)

Ethernet mode

• The 2 ports X1 and X3 are in operation - the device works as a media converter
• Different speeds (10Mbit, 100Mbit, 1Gbit) can be applied to port X1 and X3.
• The device works in store-and-forward principle
• Port X1 must be equipped with a SFP (see following SFP note)
• The device supports “Link Loss Forwarding” and reports the link loss in the direction indicated by the arrow.

Application notes for SFP modules The SFP is not sold by Beckhoff as an accessory and is not part of the scope of delivery. The SFP tested by Beckhoff should preferably be used. A functional guarantee and compatibility with all SFPs available worldwide cannot be given by Beckhoff. When procuring the SFP individually, the following points must be observed: - no use of 100 Mbit modules, only 1Gbit SFPs are permitted - no SFP+ modules (SFP+ means >1Gbit) - Matching light wavelength - the power consumption of the SFP must not exceed the power of the carrier device, see technical data there - the SFP must have a maximum permissible operating temperature of at least 85°C In EtherCAT operation, the SFP used must not impair operation (link control, timing).