Timekeeper™
Users Manual
01/11/20
The AC/DC power status can be checked by observing the 60Hz SYNC signal. An oscilloscope or multi-meter will
help when observing this signal. This signal will have one of the following states.
•
Steady logic low indicates battery operation.
•
Steady logic high indicates DC power applied.
•
Pulsing at the 60 Hz rate indicates 60 Hz AC power applied.
•
Pulsing at the 50 Hz rate indicates 50 Hz AC power applied.
Clock SYNC signal status monitoring system.
An indicator that visibly signifies whether or not the 50/60Hz sync is being received. In the timer mode, the PM LED
is on permanently if no 50/60Hz sync is detected.
While in clock mode, the center colon reflects the same information as the clock LED. The clock LED will be used to
indicate the status of the clock SYNC signal. When the clock LED is off, the unit is in the timer or tally mode.
No sync signal is being received.
•
When the clock LED is on steadily, no sync signal is being received.
•
In this mode the clock is the least accurate. In this mode, the clock has an accuracy of the internal crystal.
The 32KHz is generating the sync signal.
This is not available on all models.
•
The clock LED flashes once every 2 seconds.
•
When the clock LED is making very short flashes one per second, the internal 32KHz crystal is generating
the SYNC signal.
•
In this mode the clock is the much more accurate. In this mode, the clock has an accuracy of 20 parts per
million.
External 50hz sync has been detected.
•
The clock LED blinks on/off every 2 seconds.
•
When the clock LED is on for two seconds, then off for two seconds, the timer is receiving a SYNC signal
from a 50Hz AC line.
•
In this mode the clock is the most accurate. The clock is as accurate as the AC line frequency. In most
countries the accuracy is within five seconds per year.
External 60hz sync has been detected.
•
The clock LED blinks on/off once per second.
•
When the clock LED is on for one second, then off for one second, and continues to repeat this pattern, then
the timer is receiving a SYNC signal from a 60Hz AC line.
•
In this mode the clock is the most accurate. The clock is as accurate as the AC line frequency. In most
countries the accuracy is within five seconds per year.
Timekeeper™ wiring diagram examples are available in separate documents.
See the specific application note that best fits your application.
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