16-channel DI with interrupt capability
The Siemens 6ES7321-7BH01-0AB0 is an SM 321 digital input module providing 16 channels at 24 VDC, with a rated input current of 7 mA per channel for signal "1". It supports parameterizable hardware interrupts and diagnostic alarms, making it suitable for time-critical applications where an input event must trigger a CPU response immediately. The module draws up to 130 mA from the backplane bus at 5 VDC and up to 120 mA from the load voltage supply at 24 VDC.
Field wiring and integration
The module occupies a single S7-300 slot with dimensions 40 mm wide × 125 mm high × 120 mm deep, fitting standard DIN-rail mounted enclosures. A 20-pin front connector is required for field wiring; the module supports 2-wire sensors and includes electronic short-circuit protection and reverse polarity protection on the sensor supply. Wire-break detection is active when input current falls below 1 mA, and the input filter time can be set to 0.1 / 0.5 / 3 / 15 / 20 ms per channel group.