The Rollcentre LT 32 Lap Timer

Operation

A single button on the display unit is used for all functions. To switch On, press the button until a series of four dashes “----“ appear. This indicates that the display is ready to accept the first trigger. Releasing the button before the dashes appear will not power up the display.

As the receiver passes the beacon for the first time, all zero’s “00.00” will be displayed. On the next pass, the lap number is first displayed in the format “L 01” for lap one. This is displayed for two seconds before the lap time is shown.

Once the receiver is triggered no other triggers are accepted for the next 5 to 60 seconds, depending on the “Blanking” figure set. This is to prevent the system being triggered by other beacons around the circuit.

If from switch on the unit is not triggered within 10 minutes, it automatically switches off.

The Display will show lap times off up to 1 minute as say 57.99, between 1 and 2 minutes as say 1.35.26, but over 2 minutes as say 05.34.instead of 2.05.34 This is because the display cannot physically display a 2, so a little common sense is required.

Displaying stored lap times

The display will store the first 32 lap times. To recall them press the button momentarily. The message “LAPS” will be displayed. Each short press of the button will then step through the lap number and time.

Switching off the display

To switch off, keep the button pressed until the message “OFF” appears. The display will power off when the button is released.

The Transmitter

The transmitter is On when the switch is in the forward position, i.e. when towards the output window. A red LED is visible through the Window when switched on.

Receiver Sensitivity

The receiver sensitivity can be set using the button on the display. However the sensitivity level should not need changing from the initial setting of 6.

To change, press the button to switch on, but leave pressed until the message “SEN” appears. Releasing the button, then pressing the button again and keeping pressed, the level of sensitivity will slowly scroll through. The range is from 1 to 9, and a factory test mode, with level 9 being the most sensitive. Release the button when the required level is displayed, generally 6.

Trigger Blanking

The receiver is not coded and will trigger from other LT32 Beacons, as well as those from most other manufacturers. To prevent unwanted triggers from other beacons around the circuit a blanking function is used. This works by not accepting another trigger for so many seconds after last accepting a valid trigger. This value can be set between 5 and 60 seconds in 5-second steps. 

It sounds complicated, but it’s very simple. As your vehicle goes past the pit wall for the first time it sees an infra red beam, the first beacon on the pit wall. It doesn’t matter whose beacon it is. It then switches off the receiving part of the timer for the blanking time set, i.e. 30 seconds. So for 30 seconds it will ignore all other beacons  then when the blanking time elapses, it sees the first beacon on the pit wall again. Also if someone has a beacon half way round the circuit, you can set the blanking time to ‘blank’ it out. The MAJOR ADVANTAGE of this is that you will not need to waste time at the circuit checking that other drivers aren’t using your frequency, giving you unwanted times.

To set the blanking value, instead of releasing the button when switching off, keep it pressed in until the message ”bln” appears then release. The pre-set value will then be displayed in the form “b 35” for a 35 second value. To change the value, press the button and the different values will be stepped through. Release the button when the required value is displayed. The initial blanking time set is 30 seconds.

 It is important that the blanking time is not greater than the lap time. Make sure of this especially when going to a new track.

Battery Requirements

Power for the display is provided by a PP3 size battery, and by four AA size batteries for the transmitter. It is recommended that alkaline type batteries, such as Duracells should be used. With Alkaline batteries, each should provide a minimum of 30 hours continuous use. A low battery symbol appears on the display when the battery is going flat.

 A dim LED and a reduced transmitting range indicate flat batteries in the transmitter. The battery life using alkalines should be around 20 hours.

Installing the unit

 The display can be mounted on the steering wheel, dash, fork yolks or fairing, in fact wherever the driver can view it with ease. Industrial type Velcro is the best method for securing. The receiver wants the small round window pointing squarely at the transmitter as it passes it. Ensure that the window is not obscured and free from dirt.

The transmitter has a nut in the base into which a standard camera tripod can be screwed. Alternatively the transmitter can be rested on the pit wall. Ideally the transmitter should be at the same height as the receiver, and pointing at the position of the receiver as the vehicle passes it.

As a guide, the beacon and receiver’s exact alignment is not critical, but just make sure that they are pointing at each other.

Tips

If you have problems at the circuit they are generally caused by:

• · Receiver not pointing at the beacon.
• · Blanking value set longer than lap time…lap times are double what they should be.
• · Blanking value set too low…two or more times per lap that are regularly similar.
• · Sensitivity too high….spurious lap times, interference from low sun.
• · Sensitivity should normally be set at 6
• · Sensitivity too low….. no or occasional lap times.
• · Lead too close to ignition leads….spurious lap times
• · BIKES….Make sure that the receiver is pointing at the transmitter at the beginning of the pit wall. This is because, say for example at Brands Hatch, the bike is heeled over for a long time past the pits, with the receiver pointing at the ground….as the bike straightens up, it will get a trigger from way down the pit wall, and it may not be the same one each time. This will not happen if you point the receiver up to compensate for the lean of the bike.