16 inputs at 48 V AC — the Modicon Quantum 140DAI44000
The 140DAI44000 is a 16-channel discrete input module for the Modicon Quantum automation platform, accepting 48 V AC field signals. It sits in a standard-format Quantum rack slot and draws 180 mA from the backplane bus. Each input is isolated from the others and from the backplane at 1780 Vrms for one minute — that's the channel-to-channel and channel-to-bus isolation rating. For a 48 V AC module this is generous headroom, meaning you can run mixed-voltage field wiring on adjacent channels without worrying about sneak paths.
Input current and response time — the scan-cycle numbers
The module draws 11 mA per input at 57–63 Hz and 9.3 mA at 47–53 Hz, with a capacitive input impedance of 5600 Ω and 6800 Ω respectively. That impedance matters when you're sharing a transformer with other loads — the 140DAI44000 doesn't load the AC supply heavily. Off-to-On response time is 4.9 to 0.75 ms times the line cycle (depending on the line frequency), and On-to-Off is 7.3 to 12.3 ms. At 50 Hz that's roughly one half-cycle for turn-on and under one full cycle for turn-off — fast enough for most discrete sensing but worth budgeting in a high-speed counting application. The voltage thresholds are defined per frequency band: state 0 is guaranteed at 0–10 V, state 1 at 34–56 V AC (57–63 Hz) or 36–56 V AC (47–53 Hz). Maximum leakage current is 1.7 mA — if your sensor's off-state leakage exceeds that, the module may see a false-on. The absolute maximum input is 100 V for one cycle, 63 V for 10 seconds, and 56 V continuous.
Lifecycle and compliance — active, CSA/UL, CE
Software support covers Concept, Unity Pro, and ProWORX 32 — the three Quantum programming environments. The module uses 1 input word of backplane addressing. Altitude rating goes to 5000 m — fine for high-altitude installations without derating.
Panel diagnostics and EMC immunity
Front-panel LEDs give you bus communication (green), external fault (red), and per-channel input status (green) — 18 LEDs total. That's enough to troubleshoot a dead channel without a laptop. EMC immunity is specified per IEC 801: 9.1 V/m radiated field (10 V/m) from 80 to 2000 MHz, 4 kV contact ESD, and 8 kV air ESD. Maximum power dissipation is 5.5 W — factor that into the enclosure's thermal budget if the rack is densely populated.