User manual

223

Time Synchronization

XL2 User Interface

The clock delimiter signals the state of GPS time detection.

GPS time signal is synchronized with GPS

(locked).

GPS receiver connected, but time signal not

synced with GPS (unlock).

GPS time signal not found, receiver is not

connected or XL2 not conﬁgured for GPS.

When starting a GPS time-synchronous measurement you ob-

serve the following characteristics:

After starting the measurement, the start

counter in the button will remain at 1 for up

to 10 seconds.

Exactly 4 seconds before a full 10 second

time jump, the button changes and the mea-

sured values and the timer value of the pre-

vious measurement are reset.

The measurement begins exactly at the

10-second jump.

Start without GPS

If the XL2 has not received a valid GPS information until the

start time, the internal XL2 time will be used as time. The XL2

time is set by the NetBox.

If the NetBox has connection to the network before the start

time, then the time of NetBox is precisely synchronized via

NTP. The start is precise to about 10 ms. If the NetBox could

not yet be provided with an exact time by NTP at the start, then

the NetBox time deviation is approx. 20 ppm since the last syn-

chronization (this corresponds to one error per day of

24 hours * 3600 * 20 / 1e6 = 1.7 sec.

As soon as the XL2 receives a valid time information via GPS,

the time deviation is logged in the log ﬁle.