The SITOP SEL1400 8-channel selectivity module distributes a 24V DC supply across up to eight individually protected load circuits using a current-limiting characteristic — instead of switching off on brief overloads, it clamps output current to the preset threshold, allowing short-term inrush peaks from motors and capacitive loads without nuisance tripping.

Current-Limiting Protection

Unlike switching-type modules that disconnect a branch immediately upon overcurrent, the limiting characteristic holds the output at the set threshold for up to 5 seconds before shutting down. This is particularly valuable for loads with high starting currents, such as solenoid valves, DC motors, or LED drivers with large input capacitance. Each channel's threshold is independently adjustable between 1A and 5A via a front-panel potentiometer.

Monitoring and Diagnostics

Each output has a three-color LED (green = OK, orange = manually off, red = tripped) for at-a-glance status. A floating common signaling contact (NO, 30V DC/0.1A) reports group faults to a PLC or annunciator. The module also supports sequential startup of outputs, reducing the cumulative inrush current drawn from the upstream power supply during system power-on.

Installation

The module snaps onto a standard 35mm DIN rail (EN 60715) and measures 45mm wide, occupying minimal cabinet space. Push-in terminals accept 0.5–16mm² conductors without tools. Operating temperature range is -25°C to +60°C with natural convection, derating 2%/K above 60°C up to +70°C. Protection rating is IP20 (Class III).