Two-channel analog input slice for the TM3 rack
The Schneider TM3AI2H is a two-channel analog input module that fits the Modicon TM3 I/O bus. It accepts voltage (0..10 V, -10..10 V) or current (0..20 mA, 4..20 mA) signals, resolved to 16 bits (15 bits + sign). The LSB is 0.153 mV on the 0..10 V range and 0.305 µA on the 4..20 mA range — fine enough for most process transmitters. Each channel converts in 1 ms plus 1 ms per active channel plus one controller cycle, so a two-channel scan adds roughly 3 ms to the bus cycle. Cross-talk stays within 1 LSB. Non-linearity is ±0.01% FS; repeat accuracy ±0.5% FS. For a 16-bit input used in a closed-loop control line, that’s reliable enough for moderate-speed analog regulation.
Mounting and wiring to the rack
The module clips onto a TH35-7.5 or TH35-15 DIN rail (IEC 60715) or mounts to a plate with the optional fixing kit. Dimensions are 90 x 23.6 x 70 mm (H x W x D) — one half-width slot on the TM3 rail, leaving room for a neighbor module that needs a wider face. The removable screw terminal block (11 x 2.5 mm², 5.08 mm pitch) handles inputs and 24 V supply. Schneider specifies twisted shielded pair cable up to 30 m per input. Input impedance is ≥1 MOhm on voltage channels, and the module tolerates a continuous overload of 13 V or 40 mA without damage — useful if a loop is accidentally jumpered to a higher voltage during commissioning. Current draw from the backplane: 30 mA (no load) or 40 mA (full load) at 5 V DC, plus 25 mA from the 24 V sensor bus.
Lifecycle and supply posture
No direct replacement exists because the module is still active.