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
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 by using the XML standard
(or over the PROMOTIC "socket" interface
, that is now considered obsolete).
2nd Web client that views the data in the form of HTML pages (data or panels) from the PROMOTIC Web server. For viewing HTML pages, for example, the MS Internet Explorer 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 under the PROMOTIC system: for example, communication with PLC's, creating user algorithms, etc.
3rd Another application that reads/writes the XML data.
From business point of view we distinguish two types of clients
- "runtime" licences:
This licence enables to:
- Receive and send data by the XML
standard (or the old fashion way by Sockets
). These are the following data transfers:
This licence enables everything like the "PmDataClient" and moreover it enables to view and get data from subsystems:
- On-line viewing application panels as automatically generated dynamic html page
, so-called Web panels
: 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 enables 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 PC stations 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 the 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
Maximum and current count of connected clients can be found in the runtime mode by the Pm.LicenceInfo