What it is and where it fits
The Siemens 6ES7924-0BE20-0BC0 is a connection module designed for SIMATIC S7-300 and S7-1500 systems, specifically to relay digital input signals from the front connector to the I/O module. It mounts on either 35 mm or 15 mm DIN rail, with any orientation allowed, making it flexible for tight panel layouts. Rated at 50 V and 1 A, it handles the signal-level currents typical of digital inputs. The 20 terminals are arranged as 8 input pairs (I x 2) plus 2 each for L+ and M, giving you a clean, dedicated path for field wiring back to the module. The push-in connection type accepts stranded wire from 0.2 to 2.5 mm², and a 3.5 mm screwdriver blade is specified for release. No shield connection or PE connection is provided on this module — those are handled upstream at the I/O module or cabinet ground bar.
What the ratings mean for fit
The 50 V rated value and 1 A current are the maximums for the module's internal bus; they do not limit the field-side sensor voltage. The module is a passive interconnection — it passes through the signal from the front connector to the I/O card, so the actual voltage and current on the field wires are determined by the connected sensor and the I/O module's specifications. Operating temperature range is 0 to 60 °C, with storage from -40 to +70 °C. The pollution degree 2 and overvoltage category 2 ratings confirm it is suitable for standard industrial control panels without harsh chemical or conductive dust exposure.
Installation notes from the field
Maximum cable length between the front connector module and this connection module is 30 m. For runs approaching that limit, use twisted-pair cable to maintain signal integrity. The module does not require an end cover plate, and it supports an infeed function for daisy-chaining supply voltage to additional modules. Each terminal can accept up to two wires in a ferrule, as long as the combined cross-section stays within the 2.5 mm² limit. The single-contact NO relay design per channel means no mechanical latching — signal state follows the input directly.