Signal Conditioner Unit (SCU)

Overview

The Signal Conditioner Unit’s (SCU) basic function is to excite the fuel probes, compensator, and temperature sensors and scale the return signals. Each SCU can interface with up to eight (8) fuel probes with temperature detection and/or fuel probes with compensators. It will process capacitive and resistive readings to determine the fuel heights for each probe and transmit the calculated fuel volume to the cockpit.

Enclosure

• Material: Nickel plated aluminum
• Dimensions: 4.4” x 6.1” x 1.8” (11×15.5×4.5cm)
• Weight: 1.25 lbs (565 grams)
• EMI Filtered Connector to Aircraft: MS3114L14-19P
• EMI Filtered Connector to Fuel Tank: MS3114L16-26P

Features

• Startup and Continuous Built-In-Test (SBIT and CBIT)
• Fuel temperature measurement
• No field calibration required when paired with LMS probes and sensors
• Slosh filtering
• High- and Low-Level detection

Operational Temp. Range

• -55° C to +75° C

System Accuracy

• MIL-G-26988C Class II (±2% indication, ±0.75% full scale
  
  • No Compensator Required for One Fuel Type
  • Compensator Required for Multiple Fuel Types
• MIL-G-26988C Class I (±4% indication, ±2% full scale)
  • No Compensator Required for Multiple Fuel Types

Input

• Up to Eight (8) Probe or Compensator Channels
• Input: 28VDC
• Two (2) ID bits to select up to Four (4) different tank configurations via pin strapping

Outputs

• ARINC 429 or customer specific requirement
• Up to Two (2) Discrete Open/GND Outputs for Low and High-Level Detection

Power Requirements

• Input: 28VDC per MIL-STD-704
• Current Draw: < 100mA
• Maximum Power Consumption: 7W