The Model L-1300 incorporates a microcontroller that monitors and processes signals from the loop/lead-in circuit. The microcontroller uses these inputs to determine how to control the detector outputs. A Liquid Crystal Display (LCD), a light-emitting diode (LED), and three front panel pushbuttons are used to display and program all detector functions. Several diagnostic modes are available to aid technicians and service personnel in troubleshooting detection problems.
The LCD makes it easy to view and adjust all programmable detector options and settings. An eight-segment bar graph at the top of the LCD can be used to provide a graphical representation of the relative change of inductance as seen by the detector at the current sensitivity level. The bar graph automatically takes into account loop size, loop inductance, number of loops, number of turns, loop geometry, lead-in length, etc. The bar graph functions as a sliding scale that relates to the programmed Sensitivity Level. The first (left-most) bar graph segment represents the minimum inductance change necessary for the detector to output a call at the currently selected sensitivity level. Larger inductance changes will indicate more segments. Each additional segment indicates that the next sensitivity level has also been met or exceeded. When used in this manner, the bar graph provides an indication of whether the sensitivity is set too high or too low, facilitating the ideal setting of the sensitivity level.
The output of the L-1300 is routed to the SmartScan controller. When active, it will initiate the train scanning process.
The diagram below shows a typical track layout for a loop detector application. The loop is constructed of a single run of RR-418 4-conductor cable spliced in the juction box so as to make four continuous loops. Loop installation kits are available from STC - The 2600-912 Single Track Loop Kit includes 100' of RR-418 and hardware necessary to secure the loop to the crossties. A Double Track Loop Kit (Item No. 2600-913) is also available.
