Input Capabilities
The iTEMP TMT162 features universal input capabilities designed to interface with a wide variety of temperature sensors, enabling precise measurement in industrial applications. It supports two sensor inputs that can be configured for resistance temperature detectors (RTDs), thermocouples (TCs), linear resistance transmitters, and voltage signals, with options for single or dual sensor setups such as 1 x RTD/TC or 2 x RTD/TC.[3]
For RTDs, the device accommodates types including Pt100, Pt1000, Ni100, and Cu10, with resistance ranges from 10 to 2,000 Ω and minimum spans as low as 10 K. Thermocouples supported include types J, K, N, T, E, and others, accepting mV inputs from -20 to 100 mV, while linear resistance inputs handle 10 to 2,000 Ω (specifically 10 to 400 Ω and 10 to 2,000 Ω ranges, with maximum sensor wire resistance of 10 kΩ), and voltage signals cover -5 to 30 mV or -20 to 100 mV. RTD connections support 2-wire, 3-wire, or 4-wire configurations, with sensor excitation currents limited to ≤0.3 mA to minimize self-heating effects.[3]
Measurement accuracy varies by input type, achieving 0.1 °C for standard Pt100 and Ni100 RTDs, 0.25 °C for common thermocouples like type K, and ±0.08 Ω for resistance up to 2,000 Ω, with an overall A/D converter resolution of 18 bits. Lead wire compensation for RTDs is automatic in 3-wire and 4-wire modes, supporting up to 50 Ω per wire, while 2-wire connections allow manual compensation from 0 to 30 Ω. For thermocouples, cold junction compensation is provided via an internal Pt100 sensor (-40 to +85 °C) or configurable external value in the same range, ensuring accurate reference temperature adjustment.[3]
Configuration options for inputs include sensor type selection through the HART protocol using handheld terminals or PC software, or via the local LCD display for on-site adjustments. The device supports linearization tables and custom curves for non-standard sensors, including Callendar-Van Dusen coefficients for RTDs via the equation RT=R0[1+AT+BT2+C(T−100)T3]RT = R_0 [1 + A T + B T^2 + C (T - 100) T^3]RT=R0[1+AT+BT2+C(T−100)T3], where R0R_0R0, A, B, and C are sensor-specific constants.[3]
Output and Communication
The iTEMP TMT162 temperature field transmitter primarily outputs a scalable 4 to 20 mA analog current signal, which can be inverted to 20 to 4 mA if required, superimposed with the HART protocol for digital communication capabilities.[13] This analog output supports a maximum load determined by the supply voltage, such as up to 1348 Ω at 42 V DC, and includes trimming options for the 4 mA and 20 mA points to ensure precise alignment with control systems.[13] The HART protocol, compliant with Revision 7 specifications, enables the transmission of device description files (DD or DTM) that facilitate configuration and integration with tools like FieldCare or DeviceCare software.[13]
HART communication provides two-way digital interaction at 1200 baud using frequency-shift keying (FSK) modulation with ±0.5 mA amplitude, requiring a minimum load of 250 Ω for reliable operation.[13] Key features include support for diagnostics, such as event logging of up to five recent faults and real-time status signals (e.g., maintenance required or out of specification), as well as calibration functions like sensor trimming and current output adjustments.[13] Multivariable output is achieved by assigning measured values—such as primary variable (PV) for temperature, secondary variable (SV) for sensor status, or tertiary/quaternary variables for averages or differences—to the HART channels, enhancing monitoring in industrial setups.[13]
The signal maintains high accuracy across the full 4 to 20 mA range, with a maximum measurement error of less than 1% of the span under reference conditions, and incorporates low-noise features like a 50/60 Hz mains filter and adjustable digital damping up to 120 seconds to minimize fluctuations.[13] Fault indication is configurable via upscale (≥21 mA, adjustable to 23 mA) or downscale (≤3.6 mA) modes per NAMUR NE 43 standards, ensuring clear signaling of issues like sensor failure without disrupting overall system integrity.[13] Additionally, the output includes galvanic isolation exceeding 2 kV AC between input and output circuits for 1 minute, providing electrical safety and noise rejection in harsh environments.[13]
Housing and Display Features
The iTEMP TMT162 features a robust field housing constructed from stainless steel 316L (V4A), designed to withstand demanding industrial environments.[3] This material provides excellent corrosion resistance, making it suitable for harsh conditions such as chemical processing or outdoor installations.[3] The housing employs a dual-compartment design, separating the electronics from the terminal connections to enhance protection against moisture and mechanical stress.[4] It achieves an IP66/67 ingress protection rating, ensuring resistance to dust and high-pressure water jets, thereby supporting reliable operation in wet or dusty settings.[13]
The transmitter includes an optional integrated backlit LC display for local monitoring, featuring large digits for clear readability of measured values from a distance.[3] This display incorporates a bargraph for visualizing process trends and icons for fault indications, allowing quick identification of issues without external tools.[3] It is configurable to show process values, diagnostics, or other parameters, and can be rotated in 90° increments for optimal viewing orientation.[2]
Mechanically, the iTEMP TMT162 supports versatile mounting options, including head-mounted configurations on sensors or rail mounting for control panels, facilitating integration into various setups.[3] Its dimensions are compact, measuring approximately 112 mm in height without the display, with an overall weight of about 4.2 kg when equipped with the stainless steel housing and display.[2] The unit is engineered for protection against mechanical stresses, offering vibration resistance from 2 to 150 Hz at 3g acceleration per IEC 60068-2-6 and shock resistance compliant with relevant industrial standards.[3]