PROMOTIC uses the
client-server model for communication in LAN and the Internet/Intranet.
- The server application provides its data.
- The client application on the contrary reads/changes the data from/on the server.
The
PROMOTIC client can be:
1st
The PROMOTIC application that reads/writes the data from/to the application of the
Server type. The PROMOTIC application (client) can exchange data with the server using the
XML standard (or over the
PROMOTIC "socket" interface, that is now considered obsolete).
2nd Web client that views the information (data or panels) in the form of HTML pages from the PROMOTIC Web server. For viewing HTML pages, for example, Chrome, Firefox, Edge, InternetExplorer ... can be used. These clients can visualize (or change) the data from the PROMOTIC Web server but not all is allowed to them that is allowed to the client application created and operated in the PROMOTIC system: for example, communication with PLC devices, creating user algorithms, etc.
3rd Another application that allows reads/writes the XML data.
From business point of view we distinguish two types of
clients - "runtime" licences:
-
PmDataClient:
See
PmDataClient licence item.
This licence allows:
- Receive and send data by the
XML standard (or the old fashion way by
Sockets). These are the following data transfers:
-
PmWebClient:
See
PmWebClient licence item.
This licence allows everything like the "
PmDataClient" and moreover it allows to view and get data from subsystems:
- On-line viewing application panels as
automatically generated dynamic html page, so-called
Web panels.
-
Trends: viewing trends in the graph and table form.
Both clients licences enable to operate the client regardless of whether it is a PROMOTIC application or not. Licences for clients are stored (need to be purchased) to the PROMOTIC Web server. Then the server allows to communicate with as many clients as how many licences it has got. The licence is so-called "flying": Web clients can be started from various computers but the number of concurrently running clients must not exceed the number for which the runtime licence has been purchased. If, for example, the PROMOTIC Web server has got only one client licence, then only the first client that applies for the data, is connected. If this client doesn't apply for new data
after 10 minutes, then it is unregistered from server and a new client can connect.
But if the client application runs on the same computer as the server one and if the server address is set on the client as
"http://localhost/" or
"http:/127.0.0.1/" (this means the general-purpose address for the local computer), then this client connects to the server always as the
PmWebClient without no need to have a licence (i.e.
local client is free of charge).
- The
Development key contains 10 available clients of the
PmWebClient type for testing purposes.
- In the
PmFree type application, there are 2 available clients of the
PmWebClient type.
Maximum and current count of connected clients can be found in runtime by the
Pm.LicenceInfo method.