Model L1 – Jumbo Process Indicator

Overview
The Model L1 Jumbo Process Indicator is a versatile and robust display unit engineered for monitoring various process parameters such as Temperature, humidity, voltage, and current in industrial environments. Designed to interface with multiple types of input signals including RTDs, thermocouples, and analog outputs from transmitters, the L1 provides precise and stable readings on a large, high-visibility LED display. Its durable construction and reliable performance make it ideal for control rooms, production floors, and outdoor process areas.

Working Principle
The instrument receives signals from RTDs, thermocouples, or analog current/voltage inputs. These inputs are processed through internal filters to eliminate noise or unwanted signals, ensuring accurate readings. A low thermal drift operational amplifier enhances long-term stability, and built-in cold junction compensation (CJC) ensures accurate thermocouple readings regardless of ambient conditions. The unit also supplies excitation voltage to external transmitters, making it a complete solution for process monitoring.

Key Features

• Input Options:

  • RTDs (PT-100)

  • Current: 0/4–20 mA

  • Voltage: 0/1–3/5 VDC

  • Thermocouples (with cold junction compensation)

• Accuracy: ±0.25% of Full Scale Deflection (FSD)

• Input Configuration: Single or Dual Input support

• Transmitter Power Supply: Built-in 5 VDC, 12 VDC, or 24 VDC supply for external transmitters

• Display: 7-segment LED available in 2″ / 4″ / 6″ sizes for clear, distant visibility

• Power Supply Options:

  • 230 VAC

  • 110 VAC

  • 24 VDC ±15%

• Working Environment:

  • Operating Temperature: 0–50°C

  • Relative Humidity: 35–85% RH

• Enclosure: Sturdy metal case suitable for wall mounting

• Display Color: Bright red for maximum visibility

Applications
The Model L1 is suitable for a wide range of industrial applications where real-time monitoring of process variables is essential. Typical usage includes power plants, manufacturing units, HVAC systems, chemical processing, and any environment requiring clear, large-format display of critical parameters.