Series-LTI

Supported Applications

The Dwyer Series LTI is a 1/8 DIN digital panel meter designed for direct temperature measurement from thermocouples and RTD sensors. It features a dual-line, 6-digit LED display with automatic cold junction compensation. The series supports input types including J, K, T, E, R, S, B, N, C Thermocouples and 100 or 1000 Ω Platinum, 10 Ω Copper, 120 Ω Nickel RTDs.

With a NEMA 4X / IP65 front panel rating, the Series LTI is configured for wet, dusty, and dirty environments. The meter can be programmed in the field to display temperature on an upper line (four digits with °C or °F symbol) while the lower line displays a user-programmable tag.

Operating Conditions & Performance

The Series LTI operates within an ambient temperature range of -4 to 149°F (-20 to 65°C). Storage temperatures are rated from -40 to 185°F (-40 to 85°C), and the unit functions in humidity levels of 0 to 90% (non-condensing).

Measurement accuracy varies by sensor type as documented:

• J, K, T, E Thermocouples: ±1°C or ±2°C depending on range.
• R, S, B, C Thermocouples: ±2°C across specified ranges (e.g., -50 to 3000°F for R and S).
• RTDs: Accuracy of ±0.1°C or ±0.4°C depending on resistance type (10 Ω Copper, 120 Ω Nickel, 100/1000 Ω Platinum) and range.

The display resolution is configurable to 1° (up to four digits) or 0.1° (up to five digits). The unit includes free USB-based programming software resident on the meter for configuration without downloads.

Configuration Options

The Series LTI offers a broad envelope of configurable options including power supply, relay counts, and analog output capabilities:

• Power Supply Options: 85-265 VAC (50/60 Hz), 90-265 VDC, or jumper-selectable 12-24 VDC ±10% / 12-24 VAC.
• Relay Outputs: Configurable with 2 or 4 internal SPDT (Form C) relays. External expansion modules support up to four additional SPST (Form A) relays and digital I/O.
• Analog Output: Optional isolated 4-20 mA output converts the meter into an isolated temperature transmitter with a digital display.
• Communication & Expansion: Supports RS-232, RS-485 (Modbus RTU), and Micro USB connections. External expansion modules allow for additional relay control and digital I/O integration.

The series is UL & C-UL Listed: E160849; 508 Industrial Control Equipment and carries CE certification. Relay switch ratings are specified as 3A @ 30 VDC and 125/250 VAC resistive load, or 1/14 HP @ 125/250 VAC for inductive loads.

Key Product Differences

The Series LTI model numbering distinguishes power supply voltage and installed options:

• LTI-1xx Models (85-265 VAC): Includes base models without relays or transmitter, as well as variants with 4-20 mA output, 2 relays, or 4 relays.
• LTI-2xx Models (12-24 VDC/VAC): Mirrors the LTI-1xx option set for low-voltage applications, offering configurations with no options, 4-20 mA output, 2 relays, or 4 relays.
• Specific Configurations: Models such as LTI-121 and LTI-221 combine 2 relays with a 4-20 mA transmitter. Models like LTI-141 and LTI-241 provide 4 relays alongside the isolated analog output.

Enclosure options for multi-meter installations include Plastic NEMA 4X, Stainless Steel NEMA 4X, or Painted Steel NEMA 4 housings supporting from one to ten meters depending on the enclosure series (PME-00 through PME-30).