programmable vehicle speedometers - Veethree Instruments

PROGRAMMABLE
VEHICLE
SPEEDOMETERS
FIGURE 1
INSTALLATION OF GAUGE
After checking fit of gauge and U bracket, insert
gauge into panel and install bracket over mounting
studs. Install a washer and nut onto each mounting
stud as shown in Figure 1.
CAUTION:
MAKE SURE THAT ELECTRICAL WIRING IS
DRESSED AWAY FROM MOVING OR HOT ENGINE
COMPONENTS.
These instructions for installing, wiring, and
programming the Veethree Programable
Speedometer with Odometer should be kept with the
vehicle.
CAUTION
READ THESE INSTRUCTIONS THOROUGHLY BEFORE
PROCEEDING WITH INSTALLATION. DO NOT DEVIATE
FROM WIRING INSTRUCTIONS. INCORRECT WIRING
COULD CAUSE ELECTRICAL SHORT AND POSSIBLE
FIRE. ALWAYS DISCONNECT POSITIVE LEAD FROM
BATTERY BEFORE MAKING ANY ELECTRICAL
CONNECTIONS.
NOTE:If you must use a 12vdc unit in a 24vdc system,
use a Voltage Reducer, Veethree Part Number
6221776 in the "IGN" lead, and change light bulb to
Veethree part number 40102-007 or equal (GE400).
PREPARATION FOR INSTALLATION
1. Select a mounting location for gauge which provides
easy readability from the operating position.
Check behind mounting panel for sufficient installation
clearance.
2.Depending on Speedometer model, cut either a
3.395" +/- .032" (86 mm) or 4.625 (118mm) diameter
hole through the panel at the desired location.
3. Insert gauge into mounting hole and check for fit.
4. Fit U bracket from hardware package over
mounting studs on back of gauge (See Figure 1).
Legs of bracket may be shortened if required.
IMPORTANT:
BEFORE PROCEEDING WITH INSTALLATION
AND FINAL WIRING, SPEEDOMETER MUST BE
PROPERLY PROGRAMMED TO OPERATE WITH
YOUR EQUIPMENT. REFER TO THE
PROGRAMMING SECTION OF THIS BULLETIN
BEFORE PROCEEDING.
See Figure 2. Connect wiring to Gauge terminals
using washers and nuts supplied. Use wire colors
conforming to vehicleís existing color code.
1. Connect a wire from GND (ground) terminal of
gauge to electrical system ground.
2. Connect a wire from LT (light) terminal of gauge
to panel light switch or LT terminal of another Veethree
gauge.
3. Connect a wire from the positive IGN terminal of
gauge to positive 12-16 V DC power source.
4A. SPEEDOMETERS USING MAGNETIC
PROXIMITY SENSORS
Run a wire from the SEND terminal on back of
gauge to one terminal on Proximity Sensor. Run a
wire from the GND (ground) terminal on back of
gauge to remaining terminal on Proximity Sensor.
4B. SPEEDOMETERS USING PULSE
GENERATORS
Run a wire from the SEND terminal on back of
gauge to one terminal on Pulse Generator. Run a wire
from the GND (ground) terminal on back of gauge to
the other terminal on Pulse Generator. This is the
preferred method. Grounding this terminal to a
common chassis ground may introduce electrical
"noise" into the signal.
4C. SPEEDOMETERS USING GPS TRANSDUCER
Run a wire from the send terminal on the back of the
gauge to the white wire of the transducer.
5. When wiring is complete, connect power. Start
engine and check gauge for proper operation.
CAUTION:
BEFORE RECONNECTING BATTERY TO
ELECTRICAL SYSTEM, RECHECK WIRING TO
ENSURE ALL CONNECTIONS ARE PROPERLY
MADE. INCORRECT CONNECTIONS OR
ELECTRICAL SHORTS COULD CAUSE DAMAGE
OR FIRE IN SYSTEM. ELEMENTS OF
ELECTRICALSYSTEMS SHOULD HAVE
PROPPER FUSES INSTALLED.
SO19 Revesion 5

FIGURE 2
WIRING DIAGRAM
PROGRAMMING THE SPEEDOMETER
The speedometer is accurate on any system having a frequency at full scale between:
DIAL RANGE: FULL SCALE FREQUENCY DIAL RANGE: FULL SCALE FREQUENCY
0-30 mph 265-6599 Hz. 0-50 km/h 444-10,999 Hz.
0-85 mph 91-2337 Hz. 0-140 km/h 77-1924 Hz.
0-120 mph 133-3299 Hz. 0-160 km/h 89-2199 Hz.
0-160 mph 178-4399 Hz.
Programming the speedometer is accomplished in three steps:
STEP 1 . Determine the Full Scale Frequency (F.S.F.).
STEP 2. Calculate the Divide Number.
STEP 3. Program the DIP switch “Program” section.
STEP 1: Determine the full scale frequency (F.S.F)
NOTE: The tire revs/mile (or KM) may be obtained from the tire manufacturer; the number of pulses per generator revolution
from the pulse generator supplier, the rear axle ratio may be obtained from the chassis manufacturer; and the number of
drive and driven gear teeth may be obtained from the transmission or chassis manufacturer.
A. If using wheel mounted magnetic proximity sensor:
Tire Revs/Mile (or KM) x # of Teeth (or Slots) on wheel x Constant see below) . = F.S.F
DIAL RANGE: CONSTANT(f): DIAL RANGE: CONSTANT(f):
0-30 MPH 0.0083 0-50 KM/H 0.0138
0-85 MPH 0.0236 0-140 KM/H 0.0388
0-120 MPH 0.0333 0-160 KM/H 0.0444
0-160 MPH 0.0444
EXAMPLE: 0-85 MPH Model: Tire Revs/Mile (or KM) x # of Teeth (or Slots) x Constant(f) = F.S.F
988.7 x 90 x 0.0236 = 2100 Hz.
B. If using transmission mounted pulse generator: (You must ascertain the number of pulses per revolution produced
by the Pulse Generator used. If not one of the “pulses/rev” listed
below, contact Veethree Technical Service. The Veethree Pulse
Generator No. 9604276 is 8 pulses/revolution.
Tire Revs/Mile (or KM) x Rear Axle Ratio x (# of Drive Gear Teeth) x (# of Driven Gear Teeth) = Pulse Gen.Revs/Mile(or KM)
Pulse Gen.Revs/Mile(or KM) x Constant (see below) = F.S.F.
DIAL
CONSTANT with: DIAL
CONSTANT with:
RANGE 8 pulse/rev 16 pulse/rev 30 pulse/rev RANGE 8 pulse/rev 16 pulse/re 30 pulse/rev
0-30 MPH 0.0666 0.1333 0.2500 0-50 KM/H 0.1111 0.2222 0.4166
0-85 MPH 0.1888 0.3777 0.7083 0-140 KM/H 0.3111 0.6222 1.1666
0-120 MPH 0.2666 0.5333 1.000 0-160 KM/H 0.3555 0.7111 1.3333
0-160 MPH 0.3555 0.7111 1.3333
EXAMPLE: 0-85 MPH Model, 8 pulse/rev. generator
Tire Revs/Mile (or KM) x Rear Axle Ratio x (# of Drive Gear Teeth)˜ (# of Driven Gear Teeth) = Pulse Gen.Revs/Mile(or KM)
988.7 x 3.01 x 4 x 5 = 2380.79
Pulse Gen.Revs/Mile (or KM) x Constant = F.S.F.
2380.79 x 0.1888 = 447.59 Hz.
PAGE 2

C. If using an 8 pulse GPS transducer no calculations are required. Simply set the switches for a DIVIDE
number of 8. Set the four filtering switches 9 thru 12 to OFF.
STEP 2: Calculate the divide number:
F.S.F. x Constant (see below) = DIVIDE NUMBER (the divide number must be rounded UP to next whole number).
DIAL RANGE: CONSTANT: DIAL RANGE: CONSTANT:
0-30 MPH 66.66 0-50 KM/H 111.11
0-85 MPH 23.61 0-140 KM/H 19.44
0-120 MPH 33.33 0-160 KM/H 22.22
0-160 MPH 44.44
EXAMPLE: 0-85 MPH Model
F.S.F x Constant = Divide Number
447.59 Hz x 23.61 = 18.83 Round up to 19. The DIVIDE number is 19.
STEP 3. Program dip switches
On the rear of the speedometer there is an oval shaped black plug (See Figure 3). Upon removal of the plug two six- position
DIP switches will come into view. Also on the rear of the case is a blue label denoting the function of each switch position.
The label is divided into two sections- Programming and Filter. Only the eight programming switches are used at this stage.
The Divide number must be programmed into the speedometer in Binary Code Decimal format. That is, the TENS position and
the ONES positions must be programmed separately.
EXAMPLE: Assume a divide number of 41.
41 = 40 (TENS divide number)
1 (ONES divide number)
First, program the1. Refer to the chart on Page 4 and move
position 1 to ON and switch positions 2, 3, & 4 to OFF.
Next, to program the 40, refer to the chart and move switch.
position 7 to ON and switch position 5, 6 and 8 to OFF.
When the Divide number is 9 or below, set all the TENS switches
to OFF.
FIGURE 3
Filter dip switches
To minimize any extraneous electrical noise from interfering
with the operation of the speedometer Veethree has incorporated
filter switches to fine tune the filter band to the applica tion. The filter programming is accomplished as follows:
Find switch positions 9 through 12 on the DIP switch on the right. Refer to the chart labeled Filter Programming on Page 4.
Find the range of full scale frequencies in the left hand column that covers the full scale frequency of the application. Read
accross to the right and set switch positions 9 thru 12 as indicated.
NOTE: For applications using a Drive Ratio adapter providing 1000 Revs at 60 MPH, the Full Scale Frequency will be 189 Hz.
and the Divide number will be 8. The program DIP switches should be set with the TENS Divide numbers to the off position
and the ONES Divide numbers set for 8. The Filter programming switches should be set for the 330-347 Full Scale Frequency
positions.
Replace the oval shaped black plug. The speedometer is now fully adjusted. The Programmable Speedometer can be used
with pulse generator, magnetic proximity sensors without any additional adjustment. Veethree offers both senders for
use with speedometers.
SPEEDOMETER ACCURACY
The speedometer accuracy is determined by the magnitude of the divide number and its nearness to a whole number. When
the Divide number is a whole number (i.e. 42.00) the electronics error to the odometer and the vector movement is zero. This
would mean the only other inherent error would be the accuracy of placing the pointer on its shaft. The worst situation would
be to have a low Divide number resulting in a 0.5 fraction (i.e. 14.5). Since the program switches can only enter whole
numbers the 0.5 needs to be rounded up or down. Fractional numbers closer to a whole number result in much better
accuracy.
Example# 1: 14.5 round to 15 .5/15 = 3.33% error
Example# 2: 14.94 round to 15 .06/15 = 0.4% error
The higher the divide number the more accurate the speedometer becomes.
Example #3: 88.5 round to 89 .5/89 = .56% error
Example #4: 88.13 round to 88 .13/89 = .147% error
When designing an application using a magnetic proximity sensor it is very important to try to keep the Divide number as
close to a whole number as possible. This will keep the system error to an absolute minimum. Whole number Divide numbers
have no digital error.
PAGE 3

EXAMPLE: Assume a DIVIDE number of 41.
That is 1 ONES. Program switch positions 1 thru 4 next to the 1 in the ONES DIVIDE NUMBER column.
That is also 40 TENS. Program switch positions 5 thru 8 next to the 40 in the TENS DIVIDE NUMBER column.
PROGRAM CHART FILTER PROGRAM CHART
Ones Tens Full
Divide Switch Positions Divide Switch Positions Scale
Switch Positions
Number Number Frequency
1 2 3 4 5 6 7 8 9 10 11 12
1 ON OFF OFF OFF 10 ON OFF OFF OFF < 347 ON OFF OFF OFF
2 OFF ON OFF OFF 20 OFF ON OFF OFF 347-388 ON OFF OFF ON
3 ON ON OFF OFF 30 ON ON OFF OFF 389-546 ON OFF ON ON
4 OFF OFF ON OFF 40 OFF OFF ON OFF 547-695 OFF OFF OFF OFF
5 ON OFF ON OFF 50 ON OFF ON OFF 696-748 OFF OFF OFF ON
6 OFF ON ON OFF 60 OFF ON ON OFF 749-808 OFF OFF ON OFF
7 ON ON ON OFF 70 ON ON ON OFF 809-905 OFF OFF ON ON
8 OFF OFF OFF ON 80 OFF OFF OFF ON 906-1072 ON ON ON OFF
9 ON OFF OFF ON 90 ON OFF OFF ON 1073-1286 ON ON ON ON
1287-1497 OFF ON OFF OFF
1498-1771 OFF ON OFF ON
1772-2145 OFF ON ON OFF
> 2145 OFF ON ON ON
Correction formula for programmable speedometers
To change or correct an existing speedometer reading to a different reading, the Program Divide Number
is changed, using Switches 1 through 8 (See Figure above).
Incorrect speed reading (MPH or Km/H) x Program Divide Number
Divided by Actual Speed
= Correct DIVIDE number.
Example:
If the speedometer reads 45 MPH at 55 MPH actual speed, and the switches are set for a Program Divide # of 65:
45 x 65 = 53.18, rounded off to 53
55
In this case, the switch configuration changes from Program DIVIDE # of 65 (101001100101) to Program DIVIDE
# of 53 (110010101111) where 0 = OFF, 1=ON.
Filter switches 9-12 are listed in the chart above. Determine Full Scale Frequency with the new settings by multiplying the
new Divide # x Constant 23.61.
In the above example, 53 x 23.61 = 1,251.33. If Necessary, reset switches 9-12 to reflect the correct new
Full Scale Frequency.
PAGE 4