I-Loop Duo Signature Detector Card

The I-Loop Duo card complies to both 170/2070 and NEMA standards and is fully compatible with the existing traffic data collection system. Moreover, it is capable of scanning the vehicles over loops at a sampling rate up to 5000 Hz and generates meaningful vehicle signature data that can be utilized to classify and track vehicles. When using the I-Loop Duo cards together with our master detector card and our Traffic Monitoring HD system powered by our big data analytics engine, a single loop based counting station can be easily converted to a classification site with rich traffic system performance measures based on our award-winning vehicle classification and tracking algorithms.

The I-Loop Duo card was a product co-developed by CLR Analytics and Diamond Traffic Products.  Diamond Traffic Products is a famous traffic count and classification product provider in Oregon. USDOT's SBIR program partially sponsors the development of the product.


Overall Specification:

  • Texas Instrument (TI) ARM9 Processor (RM46L850-PGET, clocked at 200 MHz) with 1280KB Program Flash/64KB Data Flash/192KB RAM
  • TEES 2009 and NEMA TS1/2 2003 specification and thus compatible with 170 and 2070 controllers and NEMA TS1 and TS2 controllers
  • Flexibility for multiple telemetry solutions, including USB, Bluetooth, SPI, and Ethernet
  • As a stand-alone board (NEMA/170 slot not required)
  • Multiple LED’s on the front panel for showing overall power on and status
  • Low power consumption: ~40mA when operating loops (not including COM or Multi-Tech modules' power draw)
  • Wide temperature range operation (-40C to +85C)
  • Standard 170 cards – 6.875” (174.63mm) x 4.5” (114.3mm) x component height no greater than 1.14” (28.956mm)
  • Gold plated edge card connector (3.56” tall or 90.424 mm) to the 170 Bus
  • Input voltage range: 10V-27V
  • Hot swapping (connect/disconnect while live power applied to bus)
  • Auto-reset at voltages less than 10V on the “External Reset” input, or less than 18V on the DC+ input
  • Active or Low = 0-8 Volts, Inactive or High = > 16 Volts
  • Built-in lightning and surge suppression

Loop Detection Specification:

  • 2 independent loop channels that function with loops from 50 to 1,000 uH
  • 16 programmable loop frequencies (see 5for the lookup table of loop frequency and capacitance)
  • Options of different frequencies for loop impedance measurement
  • “Contact Closure” inputs option (5 ms or more to indicate a presence.
  • Transformer isolated
  • Three modes of Loop Operation: Count, Speed, and Class with user settable scan rates, detect, dropout, plus/minus, and various other higher function controls
  • Pulse or Presence style according to front panel controls or software program control for all three Loop Operation modes
  • Mechanism to reduce crosstalk and ambient noise interference
  • Signature sampling frequency up to 5,000 Hz
  • Both conventional loop detector output and the signature output through Ethernet/USB/Bluetooth/SPI ports
  • Standard “Channel Status Output” to a two-pin connector of the 8 possible statuses (pin 7 for Channel 1 and pin 20 for Channel 2)
  • Optically isolated NPN Open Collector of pin C (Collector) to pin E (emitter) for each loop signal (duration will be a minimum of 100 ms)
  • Support of reading in the Detector Unit Address from pins 3, 10, 15, & 3 and the Channel 1 and Channel 2 Delay/Extension input bits (pin 1 & 2)

Interface Specifications:

  • Five communication connections:
    • SPI – Onboard SPI Port for high speed communication (synchronous communication up to 20 Mbps) to either an external device or for factory testing and debugging (accessed by onboard connector)
    • NET – Ethernet connection on front panel running at 10/100 Mbps (No driver in the current version)
    • BLT – Built in Wireless Bluetooth 2.0 SPP Connection (LMX9838) implemented as a “Serial Port Protocol” type connection and defaults to 921.6 Kbps
    • USB – USB port on front panel (implemented with USB chip FTDI # FT2232, high speed serial interface to main CPU) uses synchronous communication up to 20 Mbps
    • JTAG – Secondary function of front panel USB interface for debugging and reprograming the host processor firmware
  • Front panel controls to set parameters for each loop:
    • Loop Frequency (capacitor selection)
    • Contact Closure Input mode
    • Sensitivity range from 0-7 (or from 1-8 if running the command LPSOFF = 1):
      • 0 = 0.64%                    4 = 0.04%
      • 1 = 0.32%                    5 = 0.02%       
      • 2 = 0.16%                    6 = 0.01%
      • 3 = 0.08%                    7 = Channel Off
    • Enable/disable channel output
  • Front panel controls to set general operating mode as follows:
    • Turn on/off minimum 100 ms Loop output activation time
    • Enable Pulse or Presence mode
    • Control operating frequency and mode as follows:
      • 0 = Count mode, 100 Hz        2 = Speed mode, 1,000 Hz
      • 1 = Count mode, 500 Hz        3 = Class mode, 1,000 Hz
    • Delay/Extension mode:
      • 0 = Normal mode                    2 = Extension Mode
      • 1 = Delay mode                      3 = Unused
    • Delay or Extension time in 0.5-second increments
      • 0 = 0 sec            1 = 0.5 sec     2 = 1 sec
      • ...
      • 62 = 31.0 sec     63 = 31.5 sec
  • Front panel Reset switch with two LEDs which stay on when outputs are active (the system will revert to last control settings if Reset is held down)

Software/Firmware Features:

  • Failsafe operation with faulty loops (open loops will trigger a Loop Detect)
  • Debugging modes to allow tracing of all input/output on communication channels
  • Firmware upgradable through any port (SPI, USB, NET, or BLT)
  • Reprogram through USB JTAG connection
  • “Delay” function on each loop from 0 to 30 seconds to block further trips on the loop during the delay time
  • Support of “Extension” function (if a vehicle activates the loop during the “Extension” time, the loop output is blocked until the vehicle leaves and the extension time is reset)
  • Standardized “packet” format of signature data for communication with outside hardware and software
  • Continuous outputs in a stream whenever a vehicle is detected to eliminate potential buffer overflow conditions in stop-and-go traffic


Current Status: Available now and can ship immediately.