Ex. 2)
If the measuring distance is extended to two kilometers (or miles) or shortened to 500 meters (or half a mile), double the scale figure or reduce it by half, respectively. The tachymeter is particularly suited for use in a rally, speedway or circuit race.
90 (40 seconds position) x 2 km = 180 Km/h (mph) 90 (40 seconds position) x 0.5 km = 45 Km/h (mph)
(2)To measure work accomplished in an hour.
The tachymeter is extremely useful in calculating factory operation efficiency and measuring machine production capacity.
Ex. 1)
For example, if it takes 20 seconds to complete one job, the figure outside “20” on the dial indicates 180 on the tachymeter scale. This means that 180 jobs will be completed in one hour.
180 (20 seconds position) x 1 job = 180 jobs per hour
Ex. 2)
If 15 jobs are accomplished in 20 seconds, multiply the scale figure of 180 (showing 15 jobs in 20 seconds) by 15 and the work amount in one hour is 2700.
180 (20 seconds position) x 15 jobs = 2700 jobs per hour
ILLUMINATING LIGHT
Pressing “B” in the TIME or CALENDAR display illuminates the display for easy viewing in the dark.
BATTERY CHANGE
The miniature battery which powers your watch should last approxi- mately 2 years. However, because the battery is inserted at the factory to check the function and performance of the watch, its actual life once in your possession may be less than the specified period. When the battery expires, be sure to replace it as soon as possible to prevent any possible malfunction. For battery replacement, we recommend that you contact an AUTHORIZED SEIKO DEALER and request SEIKO SR920W battery.
Note: If the light is used for more than 5 seconds a day, and/or the alarm for more than 20 seconds a day, the battery life may be less than the specified period.