FULLY AUTOMATED OR ATTENDED, BOTH SHARE SOME CHARACTERISTICS
Manufacturers of most barrier arm gates build their devices to activate in one of two different ways. Fully automated by remote stimulus and/or manually controlled by a parking lot attendant.
Many parking lot control arms are activated when a driver pulls up to a parking lot gate in a vehicle. As the vehicle arrives, an electronic signal is sent to the arm mechanism due to the detection of that vehicles large metallic presence interacting with an in-ground magnetic field. This
in- ground magnetic field is created from buried wires known in the trade as an induction loop. The signal generated from this “activation or approach magnetic induction flux loop” often is connected to a ticket printing device. This piece of equipment is commonly referred to as a “Ticket Spitter”. The “Spitter” issues a ticket, usually for single vehicle access prior to activating the barrier arm gate mechanism causing the arm to raise. An alternative method to get the control arm raised requires a driver to reach out of the car and push a button to receive a parking lot access ticket from the “Spitter”. (In that mode of operation, it is probable that there is no magnetic loop in place.) In either case, once the ticket is taken by the driver, the “Spitter” sends a control signal to the gate arm mechanism, and the arm is supposed to raise, generally for a single vehicle to control access to the parking lot.
As the vehicle transitions from the approach location where the ticket is issued, once the control arm raises, there is usually a functioning magnetic flux or induction “Safety Loop” located under the control arm swing location which provides protection for a vehicle until it has cleared the “Zone of Danger” underneath the active arm. The control arm may also be kept in the open position by a timer that holds the gate arm up for a predetermined time prior to closing. Using a timer function in place of an in-ground magnetic loop is risky, as vehicles may not clear the opening, or another vehicle can attempt to gain access without receiving a usage ticket. Older, non-current standard compliant installations have been seen without any consistency of design or operational function.