1. UNITRONICS
GPRS

2. About GPRS GPRS - General Packet Radio Service
GPRS is packet based wireless communication service offered by some GSM cellular providers.
GPRS promises continuous connection to the Internet via cellular network for mobile phone, computer users and PLCs.
With GPRS connection, the user pays for transferred Kbytes and not for call time. In theory GPRS packet-based services cost users less than circuit-switched services.

3. GPRS & Unitronics OPLC
After GPRS connection established between PLC and PC you can use Unitronics software to:
Download, upload, and edit the controller program.
Read and write data to/from controllers via Remote Access or other
Unitronics' communication utilities.
Log PLC data via the DataXport utility.

4. GPRS & Unitronics OPLC Connect to SCADA via UniOPC server or Modbus
establish connection between Unitronics OPLCs and transfer data
(using for example MODBUS protocol).

5. Before We start… Requirements:
GSM Modem which supports GPRS functionality. Currently Vision
OPLC can work with list of modems
GPRS service must be supplied by the user's cellular service provider
The GPRS modem must be prepared to PLC side
PC with direct internet access using public IP

6. Registration
Before exchanging data, OPLC must register to the provider’s cellular network.

7. Registration
After successful registration the controller will receive IP address. This address usually is temporary – each time you register you receive new IP.
The IP address is one of the provider’s LAN. Usually, without special agreement with the provider, you cannot access this address from outside LAN.
That’s why the standard procedure is, when the controller calls the remote PC.
The remote PC needs to be already in Listen mode.

8. Listen
Sometimes you will want to exchange data between two controllers or controller and other device, located in the same LAN.
In some cases, after agreement with the provider, it’s possible to access the controller from outside cellular LAN.
In this cases the OPLC can be configured to Listen mode.

9. End connection
When we want to end the data transfer with specific device, we perform End Call.
If our device is in Listen mode, we can Stop Listen.
We can end the session with Unregister from network.

10. Thank you!