Technical data

Glossary • 347
WAGO-I/O-SYSTEM 750
BACnet/IP Controller
Property
Objects are described by specific properties and values. In this manner, ob-
ject information, such as name, status and behavior of an object can be read.
Properties may be editable and readable (R), readable and writable (W) and
optionally readable and/or writable (O). Access to object properties is gained
using Services.
The properties Object_Identifier, Object_Name, Object_Type and Pre-
sent_Value are common to all Objects. Other properties are object-specific,
depending on the function.
Protocol Implementation Conformance Statement (PICS)
The Protocol Implementation Conformance Statement (PICS) described ob-
jects and functions supported by BACnet devices. This is a standard docu-
ment that must be filled in by the manufacturer. When linking different sys-
tems, the PICS and the BIBBs for the devices contained therein are com-
pared with one another.
Proxy Server
Proxy means agent or representative. A proxy server (or proxy gateway) al-
lows indirect access to the network by systems, which do not have direct ac-
cess to the Internet. This may be systems that are restricted from direct ac-
cess by a firewall for security reasons. A proxy can filter out individual data
packets between the Internet and a local network LAN to enhance security.
Proxies are also used to limit access to particular servers.
In addition, proxy servers can also have a cache function. In this case they
check whether the respective URL address is already available locally and
return it immediately, if necessary. This saves time and costs associated with
multiple accesses. If the URL is not in the cache, the proxy forwards the re-
quest as normal.
The user should not notice the proxy server apart from the single configura-
tion in the web browser. Most web browsers can be configured so that they
use different or no proxy gateways per access method (FTP, HTTP).