Siemens 6ES7921 Series Front Connector for Use with Digital I/O modules

This front connector provides a modular connection Interface for Siemens S7-1500 digital I/O arrangements, offering a Compact means to link module wiring to the control system. It is intended for direct mounting on compatible I/O modules and supplies the potential feed via screw terminals, operating within typical industrial ambient temperatures.

• 24V DC rated operating voltage for standard PLC supplies
• Maximum continuous current 1A per contact to protect channels
• Total current capacity 2A for horizontal mounting arrangements
• 50‑pole IDC Interface for high‑density signal routing
• Screw‑type supply terminals with 3.5mm blade compatibility
• Operating temperature range 0 to 60°C for on‑site reliability

• Suitable for connecting digital module cable looms to S7‑1500 racks
• Used with PLC systems requiring discrete I/O channel aggregation
• Ideal for retrofit of control panels needing modular front connections
• Can be used for internal system potential distribution via screw terminals

Each supply Terminal accepts a combination of one or two conductors until the summed cross‑section limit is reached, with stripped length 10 mm.

The connector supports flexible and finely stranded conductors 0.5 to 2.5 mm², and core end processed conductors 0.25 to 1.5 mm² with end sleeves per DIN 46228.

The maximum wire length between the front connector module and the Terminal module is 30m.