Operation
CMi4140 can be configured in two ways, either via the Elvaco OTC App, or via downlink commands. Configuration via the Elvaco OTC App is highly flexible, and all configuration options available in the module can be set. In contrast, downlink configuration comes with some limitations, as not all options are available. For a detailed view of which options are available, see Downlink configuration options.
Important
Before relying on downlink configuration, make sure you fully understand its accessibility limitations and restricted option set.
Tip
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If the module is mounted inside a MULTICAL® 403, the NFC field is easiest to access by placing your phone in the center of the raised section on the back.
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MULTICAL® 603 has two module slots. If mounted in the left module slot, the NFC field is easiest to access by placing your phone in the center of the raised section on the back. If the module is mounted in the right module slot, place your phone to the right of the higher part of the back.
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If the module is mounted in MULTICAL® 803, the meter needs to be open to access the NFC field. Place your phone close to the CMi4140 when making the NFC scan.
The transmit interval is used to set how frequently the module should transmit data on the LoRaWAN® network. The parameter can be set to a value between 10 and 1440 minutes (i.e. from 10 minutes to once per day). It is possible to fix the transmit interval, but for battery-operated devices where battery lifetime is critical, Elvaco recommends using the EcoMode feature, which adapts the transmit interval depending on prevailing radio conditions.
The following table shows the transmit intervals that the module will use for different data rates in order to achieve an 11-year battery life.
Table 279. Transmit intervals for different data rates in EcoMode
|
Data rate |
Transmit interval |
|---|---|
|
DR0 |
180 min |
|
DR1 |
120 min |
|
DR2 |
60 min |
|
DR3 |
30 min |
|
DR4-DR5 |
15 min |
The following table shows the transmit interval for different data rates when using a message format with two telegrams, such as the Scheduled Extended+. Sending two telegrams instead of one will double the possible transmit interval using EcoMode.
Table 280. Transmit intervals for different data rates in EcoMode using a two-telegram message format
|
Data rate |
Transmit interval |
|---|---|
|
DR0 |
360 min |
|
DR1 |
240 min |
|
DR2 |
120 min |
|
DR3 |
60 min |
|
DR4-DR5 |
30 min |
The module relies on the meter’s clock to keep time. The meter time is assumed to be standard local time (no DST). When synchronizing time in the meter using the Elvaco OTC App, 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.
If the meter is set to use DST this is ignored by the module and the standard time is used. Thus, the time on the meter’s display may not match the time in the telegram or in the Elvaco OTC App.
ADR is part of the LoRaWAN® standard where the network server determines the optimal rate for the module based on current signal conditions. In the best radio conditions, the module will use its highest data rate (DR5) in order to be as energy-efficient as possible. When signal conditions are poor, the network server will incrementally lower the data rate until it is able to receive the message. When the data rate is low, the energy consumption per telegram will increase.
All message formats encoded to M-Bus standard will have the following structure. Each telegram begins with one byte specifying the message format. Then follows a sequence of data information blocks (DIBs). The data and structure of the DIBs depends on the message type set. Each DIB contains a data information field (DIF), a value information field (VIF) and a data field (DATA), where the actual payload is stored.
M-Bus message structure
Note
When using the message format JSON, the data will be presented as plain text, and not according to the M-Bus structure as presented above.
The product has a configuration lock feature, which prevents unauthorized access to the module. When the configuration lock has been enabled, a device-specific Product Access Key (PAK) will be needed to access the device. Keys are managed securely using Elvaco’s OTC solution which includes the mobile application for configuration.
Note
For more information about security and access control for the product, refer to the One-Touch Commissioning (OTC) documentation, available on the Elvaco website.
The module can be rebooted using the Elvaco OTC App:
To switch off the module, use the Elvaco OTC app.
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Open the Elvaco OTC app.
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Scan the module.
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Go to Apply mode.
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Set Power mode to Inactive and then Apply changes.
Payloads using M-Bus encoded data use the Function field of the DIF to indicate errors. In this case, it is set to “value during error state” (M-Bus standard EN 13757-3:2013) and the value sent should not be used. A typical case for this is when the module is unable to communicate with the meter and retrieve meter values, in which case all the fields in the payload have the DIF indicating “value during error state”. In case of erroneous data or if the module is unable to communicate with the meter, bits 4–5 of the DIF code (first byte of each index field) will be set to 11b.
Example 14. Example
A DIF code of 0x02 will be set to 0x32 in case of error. (This applies to all message formats except JSON.) For message format JSON, the actual value will be replaced with “null” in case of error state. If no meter communication is possible at all, all fields have this error indication set.
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