MONITOR Time
MONITOR time can be viewed and set via the front panel top level menu or by using the
TIME command line.
MONITOR uses an RTC (real time clock) backed by an internal battery. The RTC will
keep ticking even if the main battery to the MONITOR is removed. The RTC will, at
worst case, drift ±2 minutes per month (0 to +50C). The lifetime of the RTC battery is
about 5 years .
A GPS unit can be attached to the MONITOR via RS232 in order to provide accurate
timekeeping. Please see the section on
GPS
for details.
SDI Clock Synchronization
Certain Sutron SDI-12 sensors (such as the SDR, RLR, and the CF Bubbler) support a
command to set the time of the sensor via SDI-12. MONITOR takes advantage of that
feature, and periodically sets the clock of the sensors using an SDI-12 command,
ensuring that all devices share a common time.
Additionally, if you are using a GPS, a MONITOR, and a Sutron SDI-12 device such as
the SDR, RLR, or CF Bubbler, you may connect the GPS to the SDI-12 device rather
than to MONITOR. The correct time will then be used by the sensors and by
MONITOR. This way you will free up the RS232 port on MONITOR for another device
(such as a modem).
When recording is enabled and every 24 hours thereafter, MONITOR will perform a time
sync with all the Sutron devices that support the XDT! command. Every time sync will
be started by sending an I! command to every SDI-12 device that MONITOR has been
setup to measure. If the device replies favorably to the I! command, an XDT! command
will be issued to the device. MONITOR will then decide whether or not to sync that
device’s clock based up on time validity, the presence of a GPS (either on MONITOR or
on one of the attached devices), and the time difference between MONITOR and the
device.
The XDT set time command takes the format aXDTYYYY/MM/DD HH:MM:SS!
a is address
XDT is the command to set the date and time
YYYY is the year
MM is the month (01 to 12)
DD is the day of the month (01 to 31)
HH is the hour (military time 0 to 23)
MM is the minutes
SS is the seconds
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