Industrial AS-B840-108 Reed Relay Output Module

The Modicon AS-B840-108 is an eight-channel reed relay output module designed for Schneider Electric’s Modicon 800-series controllers, delivering discrete NO/NC relay outputs in a compact 1-slot form factor. Each of the eight channels can be configured for normally open or normally closed operation, enabling flexible wiring to external relays, valves, or other loads without swapping hardware. The module accepts a wide load and supply range for industrial use, with the discrete outputs supporting voltages from 0 to 300 VDC or 0 to 230 VAC (47–63 Hz) and a per-point continuous current rating up to 3 A (2 A switching), for a total module capacity that can reach 24 A across all outputs. Operational timing is fast, with OFF-to-ON and ON-to-OFF response times typically in the low-millisecond range (about 2–6 ms, dependent on load and drive conditions). Logic and coil power are drawn from standard rails listed as +5 V at 67 mA and +4.3 V at 400 mA, with the module occupying a single slot in the PLC rack. The AS-B840-108 uses the AS-8534-000 terminal connector and is commonly referenced with the Schneider Electric/Modicon 800-series catalog, interpreting the unit as a reed-relay output module for robust, relay-based interface needs. Optional RC snubber circuitry can be configured to suppress leakage in certain applications, and the module’s weight is around 2.62 lb (1.19 kg), supporting straightforward integration into existing control panels without excessive enclosure footprint. In short, AS-B840-108 provides eight NO/NC reed-relay outputs for reliable, per-channel switching in legacy and modern Modicon systems.