Dynalco LST-100L Tachometer - Manual (Page 2)

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 113 teeth rotating
at 1800 RPM gives a frequency of 3390 Hz.
Signal Frequency in Hz =
Signal Frequency in Hz = = 3390 Hz
2. Calculating Gate Time (In seconds)
Divide the number to be displayed on the LST-100 or LST-100L
by the corresponding signal frequency.
Gate Time = = 0.53 seconds
.
3. Gate Time Range Selection on 4-Position Switch
Select either position for each number pair on the switch:
Position 1: 0.26 – 0.72 sec. Position 2: 0.72 –1.43 sec.
Position 3: 1.43 – 2.85 sec. Position 4: 2.85 – 5.70 sec.
4. Pulse Rate Multiplier: Required gate time divided by ten:
jumper terminals 4 to 5. The input pulse rate will be multiplied
by ten times.
K
Required gate time divided by one hundred:
jumper terminals 5 to 6. The input pulse rate is multiplied by
one hundred.
(RPM) x (Teeth or Discontinuities)
60
(1800 RPM) x (113 Teeth)
60
1800 RPM
3390 Hz
© 2002 DYNALCO 145F-12034
Dynalco Controls, 3690 N.W. 53rd Street, Ft. Lauderdale, FL USA 33309
(954) 739-4300 • Fax (954) 484-3376 • www.dynalco.com • [email protected]
LST-100 and LST-100L are trademarks of Dynalco Controls
DYNALCO CONTROLS RESERVES THE RIGHT TO CHANGE THESE SPECIFICATIONS WITHOUT NOTICE.
OUTLINE AND CONNECTION DRAWING
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 A & B.
C. Adjust vernier potentiometer on LST-100 or LST-100L until its
display agrees with another precise digital tachometer.