PD 664 P-NET GPRS Interface, system overview.

A wireless P-NET solution

Communication principle

Using its built-in triple-band mobile phone, each PD 664 can establish a permanent point-to-point connection to a specifically identified P-NET Gateway Service. Via this connection, P-NET communication takes place between the remote stations and the PCs connected to that service. Communication between remote stations is also possible and all communication is done via a P-NET Gateway Service. Each remote station, which may be stationary or mobile

In the System overview above, the blue lines indicate the point-to-point connections between the P-NET Gateway Service and the Remote Stations. As illustrated, these connections run via the Internet and the GSM mobile phone network, through which GPRS operates. Communication through each point-to-point connection is encrypted.

The green lines indicate communication paths between the P-NET Gateway Service and PCs connected to the internet. Security and data integrity on these lines are ensured by the use of secure UDP.

If remote data acquisition / remote control of remote stations is required this can be done by the use of one ore more PD 602 DPIs connected to the Internet as shown. The use of secure UDP is not mandatory but is recommended by PROCES-DATA. The PD 602 DPI doesn’t secure UDP but the security can be kept on a high level by appending a rule on the PC running the P-NET Gateway Service that allows the PD 602 DPI to access the P-NET Gateway Service. More system examples are available by the use of this link System examples.

Security

· The only P-NET GPRS Gateway that a specific PD 664 interface will be permitted to connect with, will be that gateway which has been pre-defined and identified by URL or IP address within the module’s SIM card.

· All data communication between the PD 664 P-NET GPRS Interface and the P-NET Gateway Service is encrypted.

· A module can send SMS messages in the event that it cannot connect to the P-NET Gateway Service.

· The module has a built-in watchdog function, which can send an SMS message if there has been no communication with the local master within a specified time period.

SMS gateway

The PD 664 is able to send and receive SMS messages to or from mobile phones, or web based services, as shown on the figure.

A built-in function makes it possible to configure the PD 664 by sending SMS messages to the device. This can, for example, be done using the SMS Configurator tool, which is available in VIGO 5.7 or higher.

The PD 664 can be configured to send an SMS to a specific device, if connection to the P-NET Gateway Service has been lost. Furthermore, a built-in watchdog function allows the module to send an SMS in the event that communication from the local P-NET master stops. PD 664 Configuration (SMS), SMS Status Report.

System components

A system consists of the following components:

PD 664 GPRS Interface

One or more PD 664 P-NET GPRS Interfaces.

For each of them:

One SIM card, mounted in the remotely located PD 664

(GPRS service must be enabled).

Provides the option for simultaneous communication between PCs and remote stations.

No additional connection delays in communication once the PD 664 has established its initial connection to the P-NET Gateway Service during start-up.

Also provides the same functionality as a PD 663, having a built-in P-NET Light-Link to P-NET RS485 interface.

P-NET Gateway Service

The P-NET Gateway Service is a program that is installed as a service on a PC. This PC will normally be a separate PC, because it is connected directly

to the Internet similar to a WEB server.

The P-NET Gateway Service is automatically activated as soon as the PC starts running. However, it is recommended that the PC is always switched on

It is possible to establish up to 15376 encrypted point-to-point connections between each P-NET Gateway Service and defined PD 664 P-NET GPRS Interface devices.

Configuration and installation of PD 664 GPRS Interface

The configuration of a PD 664 device is stored on a SIM card. The SIM cards can be pre-configured at a central place, by transferring information from a PC to the SIM cards. The pre-configured SIM cards can then be taken to the remote stations for installation. All the field engineer has to do is:

1. Mount the pre configured SIM card in the device.

2. Connect the antenna to the PD 664.

3. Connect power (24 VDC).

Since the configuration has already been stored on the SIM card, no further configuration is needed.

The identity of the P-NET Gateway Service has also been stored on the SIM Card in the form of an IP address or URL, and the module will immediately make a connection with that P-NET Gateway Service, which will have been previously configured to recognise the serial number of the SIM card.