When should I choose a probe over a loop?

Refer to the information below when deciding between a probe or a loop for your application:

Probes

The fact that the Diablo Controls free exit (used only on exits) probe is not installed in the pavement and that the lead-in is very durable allows this configuration to be used in situations such as cobblestone pavements, poor pavements, dirt/gravel roads, and bridge decks. Minimal intrusion into good pavements is another benefit. The area of detection provided by the exit probe is smaller than that provided by a 6 foot by 6 foot loop and may be considered a point detector. This characteristic allows separation of closely spaced vehicles, good resistance to detecting vehicles or other moving objects adjacent to the installed location, and total immunity to “crosstalk” problems.

Loops

The loop (buried in the pavement) and its lead-in cable form the sensing portion of the system. The loop’s size and shape (geometry) define the detection zone characteristics. An electronic module, connected to the loop, recognizes the presence of a vehicle in the detection zone. Once the module senses a vehicle, it processes the data according to its programming. The data can be acted upon immediately (as in the case of traffic lights, gates, etc.), it can accumulate in the detector for later analysis, or the data can become a minor input to a major system. The loop can be used for both exit and safety detection. The DSP-14 detection system is required to do both.