The SITOP SEL1200 8-channel selectivity module with a 60A input rating is the high-current workhorse of the switching-type family. Eight individually adjustable outputs span 2A to 10A each, and the inverse-time switching characteristic ensures a hard short circuit on one branch is cleared in ~30ms without affecting neighboring channels.

Fast Fault Isolation at Scale

With 60A of available input current and 10A per channel, this module serves machine sections that draw substantial 24V DC power — a typical setup might feed a PLC rack, two HMI panels, a vision system controller, three valve terminals, and an I/O block, each on its own protected channel. If the valve terminal branch develops a short, it disconnects in under 30ms while the PLC, HMIs, and vision system continue operating. The faulty branch is identified instantly via its red LED and the common signaling contact.

Configurable Startup

Two DIP switches let the user choose between sequential and load-optimized startup modes. Sequential mode staggers channel energization, reducing the inrush burden on the upstream power supply. Load-optimized mode groups startup by actual demand. The delay-on-energization window is adjustable up to 5s, and remote reset via a 24V signal allows the control system to re-energize a tripped channel programmatically.

DIN-Rail Integration

Housed in a 45mm-wide DIN-rail enclosure (135mm tall, 125mm deep), the module uses push-in terminals rated for 0.5–16mm² conductors. Per-channel three-color LEDs, manual reset buttons, and the monitoring interface are arrayed on the front panel. Free SIMATIC S7 function blocks expose per-channel current, voltage, threshold setting, and trip cause over the diagnostics interface.