Details of the example scenario:
- The readings of an electric meter are to be taken every 10 minutes. Due to this being so frequent, the meter will be accessed via GPRS instead of by GSM calls in order to reduce costs.
- The energy provider (Endesa, Iberdrola, etc.) will make a conventional GSM call to carry out a meter reading once a day.
- The GSM call must take priority. When the modem receives a call from the energy provider, it must “freeze” GPRS communications to give way to the readings carried out by the provider. Once the GSM call is terminated, GPRS connections must be reestablished.
Proposed solution using MTX-65i and MTX-Tunnel.
- Readings of the electric meter are continuously carried out via GPRS and in real time from the office.
- When the electricity provider (Endesa, Iberdrola, etc.) makes the daily GSM call to the modem to read the meter, GPRS communications are frozen to give way to the call from the provider which takes priority.
- Once the GSM call is terminated, real time GPRS communications are established.
Configuration files for the MTX-Tunnel for the proposed solution:
This configuration is what must be inputted in the configuration file of the modem to be able to carry out the implementation described in the scenario.
|COMM_baudrate: 9600||Speed of the serial communication port with the PLC|
|COMM_bitsperchar: 8||Number of data bits|
|COMM_autorts: off||No flow control|
|COMM_autocts: off||No flow control|
|COMM_stopbits: 1||Configure 1 stop bit|
|COMM_parity: none||No parity bit|
|GPRS_apn: movistar.es||APN GPRS provided by the GSM operator|
|GPRS_login: MOVISTAR||Login GPRS provided by the GSM operator|
|GPRS_password: MOVISTAR||GPRS password provided by the GSM operator|
|GPRS_timeout: 0||The modem will be permanently connected|
|MTX_mode: server||GPRS connection in server mode|
|MTX_model: MTX65i||Modem model|
|MTX_ping: 35||Ping frequency to supervise the connection|
|MTX_pingIP: 184.108.40.206||IP (for example) of Google so the Ping can be carried out|
|MTX_radioBand: europe||GSM band in Europe|
|MTX_rssiLevel: 10||Red LED shown when network coverage is poor|
|TCP_port:20010||TCP port to establish the serial GPRS Gateway|
|Firewall_enabled: off||Firewall deactivated|
|CSD_enabled: on||Allows GSM calls to be received from the energy provider (Endesa, Iberdrola, etc.)|