4-channel analog input with selectable ranges
The Schneider TM3AI4G is a 4-channel analog input module for the Modicon TM3 distributed I/O system. It accepts current (0-20 mA, 4-20 mA) and voltage (0-10 V, -10...+10 V) signals with 12-bit resolution (11 bits + sign). Input impedance is >= 1 MOhm on voltage ranges, so the module loads the sensor minimally. Conversion time is 1 ms + 1 ms per channel + one controller cycle time — this is a multiplexed design, not simultaneous sampling. For a 4-channel full scan, budget at least 5 ms plus the bus cycle.
Accuracy and drift
Cross talk between channels is <= 1 LSB, adequate for 12-bit separation in a mixed-signal environment. Insulation rating: 1500 V AC between input and supply, 500 V AC between input and internal logic — protects against ground loops in a plant-floor cabinet.
Mounting and electrical
Mounts on standard 35 × 15 mm or 35 × 7.5 mm DIN rail per IEC 60715, or on a panel with a fixing kit. Dimensioned at 2.8 in deep (70 mm), 0.9 in wide (23.6 mm), 3.5 in tall (90 mm) — the narrow width packs four inputs into one slot in a TM3 bus coupler chain. Removable spring-cage terminal block, 10 × 1.5 mm², pitch 3.81 mm. Accepts twisted shielded pair cable up to 30 m. Cable type matters: the spec calls for shielded twisted pairs to maintain noise immunity at 12-bit levels. Typical current draw: 35 mA at 5 V DC (no load), 45 mA (full load), plus 30 mA at 24 V DC for the input circuitry. Budget the backplane supply accordingly. Pollution degree 2, IP20 — suitable for clean, dry control cabinets. Operating temperature: -10 to 55 °C horizontal, -10 to 35 °C vertical; derate for vertical mounting. Permissible continuous overload: 13 V on voltage inputs, 40 mA on current inputs — will survive a sensor fault without immediate damage.
Compliance: CE marked, designed to IEC 61131-2. Radiated emissions meet Class A limits per IEC 55011 at 10 m.