DTU2xx Data Logger Series
User Guide. r. 2.1 | 2021-11-10
Tel.: +420 538 890 720
17
e-mail: [email protected]
Collection and storage of information
After connecting the wires and power supply, the device connects to the server, synchronizes the date
and time parameters and automatically starts collecting data from the meters according to the preset
settings. In accordance with the given configuration, the DTU performs a continuous counting of the
number of pulses for each channel, with a cumulative total, fixing the meter readings at a given frequency
and storing the slices in non-volatile memory.
To store data, a nonvolatile memory (Flash) microcircuit is installed on the board, which stores the
following service and diagnostic information:
•
accumulated counting data on an accrual basis (number of pulses);
•
firmware version;
•
event log: history of software and hardware restarts, history of pressing the data logger setup
button, information about faults at the inputs.
The amount of stored data is determined by the time taken of the slices. With cuts with a frequency of
once an hour, the depth of the archive will be at least 10 years.
Algorithm of data logger communication
When setting up the schedule, the output of the DTU for communication with the server is set in the "hh"
format (hh - hours, minutes are not set), however, if a large number of connected data loggers
communicate at the same time, this can cause a heavy load on the server. In order to reduce the load,
each device communicates with a delay of several minutes ahead of the specified hour. The delay has a
fixed value, which is calculated based on the IMEI number of the connected DTU and can range from 0 to
60 minutes (but not more than 60 min).
SIM card operation
To reserve the GSM/NB-IoT communication channel, the data logger has two SIM card slots (2FF) with
the ability to configure an active card and support for automatic switching between cards in the absence
of communication on one of the cards. Setting the priority of SIM cards is performed only when connected
locally via a PC, in the
DTU Configuration Tool. You cannot set a priority SIM card via the web interface.
By default, the data logger is configured for the
SIM1
operating mode, which means that SIM-card 1 is
active by default, the modem works on it and if the connection fails, it does not switch to SIM-card 2. The
option
Enable control of the SIM-card activity
does not work in this case.
In
Auto mode
, data logger tries to register on a SIM card, the communication session on which was
successfully established earlier (when the data logger is turned on for the first time — on SIM card 1). If
registration is unsuccessful, data logger automatically switches to another SIM card and tries to register
on it. If the communication session was successful, the data logger remains on this SIM card.
Operating in NB-IoT network
In order for the DTU2xx to connect to the NB-IoT network, the name of the operator's NB-IoT network
through which it is planned to transfer data must be indicated in the modem module.
This parameter is called
PLMN (public land mobile network)
and is a 5-digit mobile network service area
code including the
mobile country code (MCC) and the operator's mobile network code (MNC).
