Specifications

Terminology
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APPENDIX A-TERMINOLOGY
ARCnet
The protocol used for communications between the Liebert gateway and the Liebert control modules.
This is a token-passing protocol where each module transmits information to the gateway in turn
based on its physical address.
BACnet
Data communication protocol for Building Automation and Control Networks (BACnet). It uses IDs to
identify all points that are part of the configuration, such as the SSWEB server, BACnet and ARCnet
networks, gateways and control modules. Referred to as Object IDs, these IDs make sharing
information between devices a relatively simple task using BACnet. Developed under the auspices of
the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE), BACnet
is now an American national standard, a European pre-standard, and a potential global standard.
ASHRAE Standing Standard Project Committee supports and maintains the protocol.
For details, go to:
www.bacnet.org
CMnet
The network connecting the Liebert gateway and the Liebert control modules. Daisy chain up to
50 control modules per Control Module net, or CMnet.
The CMnet can consist of any combination of the following: SiteLink-12-ARC, SiteLink-4-ARC,
SiteI/O 10/0-ARC, SiteI/O 16/16-ARC, SiteI/O 32/0-ARC, SiteI/O X8/0 and SiteTPI-M-ARC, Third
Party Interface (TPI) modules.
Control Module
A device connected to the CMnet. This includes Ethernet gateways, SiteLink modules and Site I/O
modules and TPI modules.
Ethernet Backbone
Wiring and communications equipment permitting multiple computers to share information and
resources using the Ethernet media access type.
LAN / WAN
Any Local Area Network or Wide Area Network using the Ethernet media access type.
Gateway
A device that performs protocol conversion between different types of networks or applications. The
Liebert gateway receives BACnet over ARCnet protocol from the Liebert control modules and con-
verts it to BACnet over IP for protocol communication to the SSWEB server. The Liebert SiteLink
modules receive IGM protocol from the Liebert environmental and power equipment and convert it to
BACnet over ARCnet protocol for communications to the Liebert gateway.
HTTP
Rules for exchanging files (text, graphic images, sound, video, and other multimedia files) between
browsers. Your Web browser is a hypertext transfer protocol client, sending requests to the SiteScan
Web Sever. When the browser user enters file requests by either opening a Web file or clicking on a
hyperlink, the browser builds an HTTP request and sends it to the Web server. The Web server
receives the request and returns it after necessary processing.
IGMnet
Information Gathering Module Network is the protocol that SiteLinks use to communicate to the Lie-
bert units over the EIA422 connection type. It is a point-to-point protocol, where one device connects
directly to another and only those two devices communicate with each other.