Schneider TM2ALM3LT: Specifications & Key Features
Schneider TM2ALM3LT Analog I/O Module Overview
The Schneider TM2ALM3LT is a compact analog input/output module designed for Modicon M238 logic controllers. It provides precise measurement and control for low-level temperature signals. With two analog inputs and one analog output, this module supports a variety of thermocouple types and temperature probes. Engineers and system integrators can rely on its robust specifications for accurate process monitoring.
Analog Input Specifications
This module features two analog inputs that handle thermocouple and temperature probe signals. Input types include J, K, and T thermocouples with ranges up to 1300 °C. It also supports 3-wire Pt probes (100–500 °C) with differential measurement. The input resolution is 12 bits, ensuring detailed signal conversion. LSB values are 0.1 °C for thermocouples and 0.15 °C for temperature probes. The sampling duration is up to 20 ms for temperature probes and up to 60 ms for thermocouples. Acquisition periods are 60 ms per channel for thermocouples and 80 ms per channel for other inputs, plus one controller cycle time.
Analog Output Capabilities
The single analog output offers flexible signal types: current (4–20 mA) or voltage (0–10 V). This output uses 12-bit resolution, with LSB values of 4.8 µA for current and 2.5 mV for voltage. It supports resistive loads with impedance up to 300 Ω for current and at least 2000 Ω for voltage. Stabilization time is 20 ms, and conversion time is 20 ms plus one controller cycle. This allows for responsive control in temperature regulation loops.
Electrical and Environmental Details
The TM2ALM3LT requires an external 24 V DC supply with a voltage range of 19.2 to 30 V. Current consumption is 50 mA from the external supply and 50 mA from the internal 5 V bus. The module includes a removable screw terminal block for easy wiring. It uses shielded cable to reduce noise. Insulation between channels and internal logic is provided via photocoupler, ensuring electrical isolation. Dielectric strength is 500 V between I/O channels and between I/O and internal logic. The module measures 23.5 mm wide, 70 mm deep, and 90 mm high, weighing only 0.085 kg.
Accuracy and Performance Characteristics
Measurement error is ±0.2% of full scale for temperature probes and thermocouples at 25 °C. Temperature coefficient is ±0.006 %FS/°C for temperature probes and thermocouples, and ±0.015 %FS/°C for voltage and current outputs. Repeat accuracy is ±0.5% FS for both input and output. Non-linearity is ±0.2% FS for all input types. Output error is ±1% FS, and output ripple is ≤1 LSB. Total error is ±1% FS across all ranges. Cross talk is ≤2 LSB, ensuring minimal channel interference for stable readings.
Installation and Compatibility
The module is part of the Modicon M238 range and is compatible with Advantys OTB and Twido systems. It requires an external 24 V DC power supply. Use shielded twisted-pair cables for analog signals to minimize electromagnetic interference. Attach the removable screw terminal block securely and ensure proper grounding. The compact form factor saves space in control cabinets. With its comprehensive analog capabilities, the TM2ALM3LT is a reliable choice for temperature monitoring applications in industrial automation.