Dynalco SPD-108L User Manual

SPD -108 and SPD-108L

Signal-Powered Tachometer

Calibration Instructions

The SPD-108 and SPD-108L tachometers are normally factory­calibrated to the customer-specified number of sensing teeth or

discontinuities, sensing speed, and desired numerical display.

If necessary, turn to the reverse side of this card
to calculate Signal Frequency and Gate Time.

To calibrate an SPD-108 or SPD -108L

1. Remove the sealing plug on the back of the housing.

2. Apply the calculated signal frequency to terminals 1 and 2.

A Dynalco F-16 or F-15 signal generator is ideal.

3. Select the appropriate gate time range on the 4-position
switch.

side of card.

4. Adjust the vernier potentiometer for the desired display.

See below

See label on back of SPD-108; SPD-108L; or Item 3, reverse

.

Shown with sealing plug removed

4-position switch

Vernier potentiometer

[clockwise to increase display reading;
counterclockwise to decrease]

Example:

1.Apply 3390 Hz to terminals 1 and 2 on tachometer (no polarity).

2.Turn the gate time range switch to (either) position number 2 to

select gate time range of 0.38–0.76 seconds.

3.Adjust the vernier potentiometer to obtain a display of 1800.

If 3390 Hz = 1800 RPM, then gate time is 0.53 seconds.

See label on back of SPD-108, SPD-108L for additional information

QUICK

GATE TIME

CALCULATION

(

For example: 60/113 teeth = 0.53 sec. gate time)

Number of

}

60

Teeth

Assumes the pickup is “seeing” the
gear of interest directly, not through

{

a step up or step down ratio

.

© 2002 Azonix-Dynalco 145F-12041, Rev. 1

1. Calculating Signal Frequency (in Hz)

Multiply RPM times the number of teeth (or discontinuities), then
divide by 60. For example, sensing a ring gear with 1 13 teeth rotating
at 1800 RPM gives a frequency of 3390 Hz.

Signal Frequency in Hz =

Signal Frequency in Hz = = 3390 Hz

(RPM) x (Teeth or Discontinuities)
60

(1800 RPM) x (113 Teeth)
60

2. Calculating Gate Time (In seconds)

Divide the number to be displayed on the SPD-108 or SPD-108L
by the corresponding signal frequency.

Gate Time = = 0.53 seconds

.

1800 RPM
3390 Hz

3. Gate Time Range Selection on 4-Position Switch

Select either position for each number pair on the switch:

Position 1: 0.14–0.38 sec. Position 2: 0.38–0.76 sec.
Position 3: 0.76–1.51 sec. Position 4: 1.51–3.02 sec.

Optional Calibration Method: On-engine

A. Select the appropriate gate time range on the 4-position switch.
B. Connect the magnetic pickup output to terminals 1 & 2.
C. Adjust vernier potentiometer on SPD-108 or SPD-108L until its

display agrees with another precise digital tachometer.

OUTLINE AND CONNECTION DRAWING

inches (cm)

DYNALCO CONTROLS RESERVES THE RIGHT TO CHANGE THESE SPECIFICATIONS WITHOUT NOTICE.

 (954) 739- 4300 • Fax [phone] • w w w.dynalco.com • [e-mail]

SPD-108, SPD-108L, F-15, and F-16 are trademarks of Dynalco Controls.

Azonix-Dynalco, 3690 N.W. 53rd Street, Fort Lauderdale, FL 3330 9 U.S.A.