APPLICATION GUIDE
AG082311
SITRANS RD500 GPRS Connectivity
Objective:

How to set up a GPRS connection using static and dynamic IP addressing.
Equipment:


SITRANS RD500
Internal GPRS modem and antenna


PC with Ethernet card
Internet Explorer 6.0 or higher
While every effort was made to verify the following information, no warranty of accuracy or usability is expressed or
implied.
Overview
GPRS (General Packet Radio Service) is a global standard telecommunications for data transfer. Although initially
GPRS was used in the public domain with cell phones, smart phones and mobile computing, GPRS is now widely used
for industrial applications for remote telemetry. These applications are generally know as M2M solutions.
GPRS
Manufacturing
Data center
The M2M solutions allow two-way communication between industrial equipment in the field (SITRANS RD500) and a
host system. The host system could be a server, SCADA system or other communication device. In general, the
equipment in the field will report alarm and data log information to the host system. In some applications, it is
necessary for the host system to contact the device in the field and request information or configure the device when
you turn it on. If your connection to the cell network is lost or your phone is off, your IP address is lost until you turn on
Siemens Canada Limited
Siemens Milltronics Process Instruments
1954 Technology Drive, P.O. Box 4225
Peterborough, Ontario
K9J 7B1 / Canada
Tel.: (705) 745-2431
Fax: (705) 741-0466
www.siemens.com/sensorsystems
APPLICATION GUIDE
your phone. At this point you are reassigned a new IP address. The dynamic IP address service allows the cell carrier
to re-use IP addresses and not have to worry what IP address is being used by the device in the field. The
disadvantage of dynamic IP is that you never know what your IP address is going to be so you can never get back to
your device from the host system (unless a service such as Dyndns is used).
Public Static IP
With a static IP service, the cell carrier permanently assigns an IP address to your account. When the device in the
field logs onto the network, the same IP address always is assigned to the device. The Static IP address allows the
host system to contact the device in the field because the IP address is known and allows for full two-way
communication.
Third party management of IP addresses
In some countries, the cell providers do not offer a public static IP service. Alternatively they lease a pool of IP
addresses to data management partners who manage the static IP addresses for the end user and cell carrier.
The cell carrier partners will deliver the SIM cards and assign IP address and APN login to the end users.
APN
For initial connection to the cell network whether it be dynamic or static IP an APN (Access Point) is required. An
APN is like logging into your computer, it represents login credentials to allow access to the cell network. The APN
information is provided by the cell provider.
Custom APN
A Custom APN or private IP will allow a private connection from the cell carrier to the host. In essence, the IP address
of the device in the field is not publicly available. The APN is essentially a VPN (Virtual Private Network) from the cell
carrier to the host system. Custom APNs are more expensive but deployment on a large scale would most likely
warrant the extra cost with the added security benefit.
DNS support
DNS stands for Domain Name System (or Service or Server). Basically, the DNS is a network of DNS servers that sit on the
Internet and have a database of domain names and their associated IP addresses. When you enter a Web site, for example URL
http://www.siemens.com into your web browser, a domain name server on the Internet will look up that domain name and resolve
the IP address. That IP address is then used to contact that domain.
When using DNS service in the RD500 you simply enter the IP address of your DNS server into the “DNS server name” in the
network page.
The RD500’s FTP and email client allows the user to enter a domain name. This enables the RD500 to send the datalog files to a
host whose IP address is not static. The FTP server or email client’s domain name is resolved by the DNS server specified in the
SITRANS RD500 GPRS Connectivity
AG082311
2 of 7
APPLICATION GUIDE
DNS server field on the network page. The destination IP address will be resolved by the DNS server. That IP address will be
populated next to the domain name in the FTP or email pages.
Service and feature overview
Cell plan
Dynamic
Public Static IP
Custom APN
RD500 services
Web Browser
FTP Server
FTP Sync
SMS
Email
Last Log report
Alarms
Overview Reports
Device originated Host originated
communication
communication
Yes
DYNDNS req.
Yes
Yes
Yes
Yes
Dynamic IP
Yes with DNS
support
Yes with DNS
support
Yes
Yes
Yes with DNS
support
Yes
Yes
Yes
Static IP
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Application
In this application we are going to set up a static IP address for the SITRANS RD500 using the internal modem option.
If we wanted to set up a dynamic IP address instead of a static IP, we would simply replace the SIM card for the one
with a dynamic IP. Some external modems are also supported: please see catalog for external modem options.
SITRANS RD500 GPRS Connectivity
AG082311
3 of 7
APPLICATION GUIDE
Modem Setup
1
2
Remove the GPRS internal modem from its packaging, being careful not to damage the modem.
Insert the SIM card into the holder making sure the contacts face down and the cut edge of the SIM card
lines up with the board layout.
SIM
3
4
Remove the front expansion slot cover as shown in figure 2
Insert the modem into the expansion slot. Ensure modem is seated correctly and the two locking dials are in
the locked position.
Configuring the SITRANS RD500
This application guide assumes you are already familiar with connecting direct to the RD500 via a crossover Ethernet
cable.
1
2
3
4
5
6
7
Open your web browser and enter the IP address for the SITRANS RD500: default 192.168.2.100 with the login
and password; default login is ‘admin; and default password is ‘rd500’.
From the main overview page, click on the “Configuration” tab.
In the configuration screen select the “Network” tab.
Once in the network page, set the options as below with the exception of your own APN, which is provided
by your cell carrier.
Make sure the connection type is set to “on demand” and set the frequency to your correct regional setting.
Refresh your web browser and look at the “modem status” at the bottom of the page. If your modem is
connected correctly and the SIM card is inserted you will see the current signal strength, e.g. “IDLE 17”
Be sure to set your connection type to “internal” if using the internal GPRS modem or “external” if using an
external GPRS modem.
SITRANS RD500 GPRS Connectivity
AG082311
4 of 7
APPLICATION GUIDE
Note:
Signal strength ranges from 0 to 99: a value of 99 indicates that the antenna is not connected or the internal modem is
not seated correctly.
A typical signal strength for reliable communication should be >15. See catalog for antenna options that may help
improve your signal strength.
For Multitech external modem model #: MTCBA-E the following init string settings should be used:
For SMS support, add the following in the additional init box:
SITRANS RD500 GPRS Connectivity
AG082311
5 of 7
APPLICATION GUIDE
8
Change the connection mode from “on demand” to “permanent” and refresh the page a number of times and
you will see the modem status has changed to “UP: 204.187.55.55” for example. The value after UP: is the IP
address of the modem.
You are now on the Cell network and ready to use the SITRANS RD500, test your connection by entering your public
IP address into your web browser to connect to the SITRANS RD500 vai GPRS.
On demand
If the RD500 is set to “On demand” when using GPRS, the RD500 will allow FTP sync (datalogs sent to the FTP sever
on a timed basis), reports, email alarms and SMS messages to be sent. In the “On demand” mode the RD500 will not
be accessible from remote web browsers or FTP clients. In the “On demand” mode the RD500 is registered on the
network but no data transfer will occur until the RD500 sends an FTP sync, email, alarm or report. Once an email, FTP,
report or alarm is sent, the RD500 will hang up and return to “On demand” mode after the “Connection timeout” value
is reached.
SITRANS RD500 GPRS Connectivity
AG082311
6 of 7
APPLICATION GUIDE
Permanent Mode
In permanent mode, the RD500 will register the cell modem onto the GPRS network by sending the APN information
from the network page. The cell modem will be registered onto the network and a permanent connection will be
established. A status and IP address will be shown in the “modem status” in the RD500’s network page.
In the permanent connection mode, the RD500 will allow FTP sync, email, alarms and reports to be sent. The IP
address can also be entered into the web browser to allow access to the RD500’s web server.
Note:
Not all cell providers will report the public IP address directly to the RD500 because the IP address is
being mapped internally by the cell provider. In this case, contact your cell carrier for your static IP address
information.
SITRANS RD500 GPRS Connectivity
AG082311
7 of 7