CMi6140
User’s Manual English
CMi6140
User’s Manual English
page | 18 (38)
[2022-09]
V1.2
7 Administration reference
7.1
Purpose
This chapter contains detailed information about configuring options for CMi6140.
7.2
Security and access control
CMi6140 has a configuration lock feature, which prevents unauthorized access to the module. When
configuration lock has been enabled, a Product Access Key (PAK) will be needed to access the device
via NFC. The Product Access Key is claimed by the end-user to his One-Touch Commissioning (OTC)
account via the Elvaco OTC App or the OTC web interface.
Note that the default setting of the CMi6140 is
Open
, meaning the user must set it to
Lock
to activate the configuration lock. In section 7.5, all default configurations are listed.
7.3
Scheduling readouts / transmissions
A Readout
refers to a readout of meter data and storing the information locally in the device memory.
A Transmission
refers to a sending a set of readouts from the device over NB-IoT network to a LWM2M
or MQTT-SN server.
A combination of above is set to achieve the functionality specified by the project/customer.
7.3.1 Time handling
The module relies on the meter’s clock for keeping time. Time in the meter is assumed to be in standard
local time (no DST). When synchronizing time in the meter using the OTC App, timeserver or network
time. Local standard time is always used, even if DST is in effect. The timestamped meter data sent from
the module can be adjusted to be sent in UTC by specifying the “UTC offset” configuration parameter.
The UTC offset will be subtracted from the timestamp prior to transmission. If the meter is in Sweden,
which uses CET (Central European Time), it should have UTC offset set to +60 (+1h). In this case at time
12.00 a telegram is sent with timestamp 11.00 as this is the corresponding UTC time. A meter in New
York (USA) should have a UTC offset of -300 (-5h) etc. A UTC offset of 0 means the meter time is used
as-is.
7.3.2 Synchronization
All schedules are based on a synchronization with a clock. That means that if a readout schedule of 60
minutes is used, it is synchronized on top of the hour, so 11:00, 12:00, 13:00 etc. 120 minutes will give
12:00, 14:00, 16:00 etc.
When time in the module (or meter) is synchronized a rescheduling takes place such that the next meter
readout is made according to an updated time.
To handle the case where time
synchronization “moves time” past a previously planned readout (like
23.58 → 00.02) the module will always make a readout and transmission of a new value when time is
synchronized. The device will therefore send an additional readout which can be masked on the server-
side.
7.3.3 Randomized transmissions
In order to prevent a large population of devices from transmitting data at exactly the same time the
devices should have a random delay before transmitting data. The delay should be configurable via
NFC/DM.
Readouts from the meter are always performed on top of the hour, 11.00, 13.00 etc. Transmissions can
be carried out at other times but are
planned
at full hours given a set
transmission interval
(T
transmit
). The
