How to fit a Greengauge Speedometer
Electronic Programmable Speedos (EPS)
Introduction
The EPS is a universally applicable product. No matter what the source of the speed input signal, the size of wheels or tyres or the final drive ratio of the gearbox being used, our product can be programmed by you to work within the legal limits.
IMPORTANT INFORMATION
- Only to be fitted to Negative Earth Vehicles.
- Disconnect your vehicle’s battery prior to installation
- Operating Voltage between 11 and 17 volts DC – NB the speedometer is fitted with a 12V lamp.
- The speedometer complies with CE regulations regarding electro magnetic compatibility.
Input Signals
The EPS can accept input signals from:-
- OUR RECOMMENDED SOLUTION - A magnetic sensor - using a reed switch positioned so as to be able to count the revolutions of the prop shaft, half shaft or the road wheels.This is achieved by attaching a number of magnets (usually 4) to the prop shaft, the half shaft or the inner surface of the road wheel.The sensor registers the change in magnetic field which occurs each time a magnet passes it. Each time a change in magnetic field is sensed a signal or pulse is transmitted to the speedometer.
Greengauges offers a universal speed sensor kit, consisting of the sensor itself and 6 magnets. The installer then has to provide a mounting bracket, to position the sensor and fix the magnets (on prop shaft installations 4 is the norm)using a 24hour 2 part epoxy adhesive.For speed sensor installation instructions just follow the link,speed sensor installation
- A magnetic proximity sensor positioned so as to be able to count the revolutions of the prop shaft or the road wheels. If counting prop shaft revolutions, then the sensor should be positioned parallel to the prop shaft, close to the universal joint, either where the prop shaft exits the gearbox or enters the differential. The idea is that the sensor should be able to detect the passing of the bolts on the universal joint. If counting road wheel revolutions, then the sensor should be at right angles to the wheel and could detect either passing wheel nuts or, on more modern vehicles, the cooling slots in the brake disks. The sensor detects the change in magnetic field created by the a the passage of a steel bolt or a slot in a brake disk. Each time the change in magnetic field is sensed a signal or pulse is transmitted to the speedometer.Greengauges offers a proximity sensor as an accessory under the part number EMP24-1
- A hall effect sensor,these are used in vehicles where the gearbox has the provision for a mechanical speedo cable take off, The hall effect sensor fixes into the speedo take off point and counts the revolutions of what would have been the cable drive.
- The EPS will also accept signals directly from the electronic control unit of the vehicle’s engine management system, if fitted.
Programming Your EPS
- Disconnect the battery.
- Make sure your vehicle is negative earth.
- Calculate you calibration number: -
N.B. For most of the following calculations you will need to know tne number of times that your tyre revolves per mile or kilometre.If you do need this information for your installation then stand the vehicle on a flat surface and make make a mark on a tyre, mark the floor at the same point. move the vehicle forward for one revolution of the tyre and measure the distance covered. You can then figure out how many times the tyre would revolve in covering a mile or a kilometre.
- Magnetic Sensor - using a reed switch using prop shaft revolutions,
Number of magnets x differential ratio x tyre revs per mile or per kilometre = calibration number
- Magnetic Sensor - using a reed switch, using half shaft or wheel revolutions,
Number of magnets x half shaft or wheel revolutions per mile or per kilometre = calibration number
- Magnetic Proximity Sensor - using prop shaft revolutions, Number of bolts at the universal joint x differential ratio x tyre revs per mile or kilometre = calibration number
- Magnetic Proximity sensor - counting brake disk slots or wheelnuts, Number of wheelnuts or slots x tyre revs per mile or kilometre = calibration number.
- Hall effect sensor, Number of poles on sensor x cable drive revs per mile or kilometre = calibration number.
- Electronic Control Unit, number of pulses per mile or per kilometre as declared by the engine manufacturer = calibration number.
- Convert your calibration number into a calibration switch setting using the attached table.
- Set the calibration switches. The calibration switches are a series of 10 switches to be found on the rear of the instrument under the large rubber grommet, remove the grommet by pressing above the centre and inserting a small coin or screwdriver under the raised lip and popping out the grommet. The 10 calibration switches have to be switched either on or off,on is indicated by a 1 on the switch settings, off by a zero.
For example,
Calibration number 18142 = switch setting
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 |
| 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 1 |
| off | off | off | on | off | off | off | off | off | on |
For the Calibration Number Table follow the link below:
CALIBRATION TABLE
Installation Of Your EPS
- A hole is needed in the fascia panel,the size will depend upon the diameter of speedometer being fitted, with sufficient clearance behind it to accept the body of the speedometer.
- Check again that the battery is disconnected.
- Wire the instrument as follows: -
- Green Wire – live feed to the speedometer
- Black Wire – earth (ground) connection
- Brown/Slate Wire – Only to be connected if you wish the LCD Odometer to be visible with ignition off. If required connect to a live feed.
- Red/White Wire – power for the speedometer lamp, connect to a dash lighting power feed.
- Red Wire - only needed if using a hall effect sensor, connect to a live feed.
- White/Black Wire – connection for speed signal input from the hall effect sensor or Electronic Control Unit or Magnetic sensor using a reed switch.
- Red/Blue Wire – connection for speed signal input from a magnetic proximity sensor.
- LightGreen/Purple Wire –not used, in this application.
- The speedometer can now be installed in the fascia panel hole and clamped against the rear of the panel using the fixing clamp, spring washers and knurled nuts supplied.
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