Appendix D
Address
All units in a network are given an address. The address only concerns the network in which the unit is
mounted. In each network there must only be one unit with the same address. Addresses in the range
1 - 125 can be assigned (except 124).
Baud
Unit indicating data communication speed.
DANBUSS
A data communication system developed by Danfoss A/S for communication between units.
DANBUSS datalink Master
Det er den enhed, der har Masterfunktionen på et bestemt netværk (datalink), og fore tager The
unit with the master function in a given network (datalink), handling the polling sequen ce. The unit
carrying out the master function in a network always has address No. 125. This will typically be an AKA
245 gateway.
Only one unit in a network can be designated as master.
If there are no AKA 245 units in the network, AKA 21 will automatically be the master.
Datagram
This is a packet with a message transmitted via DANBUSS.
It could for instance be an enquiry about a certain parameter, a new reference value for a controller,
the answer to an en quiry, etc.
Datagrams in a DANBUSS system can max. comprise 127 bytes, 110 of which can be information.
DCE
“Data Communicating Equipment”.
Modem arranged as DCE.
DTE
“Data Terminal Equipment”. AKA 245 and PC’s arranged as DTE.
Handshake
Control signals on an interface, e.g. RS 232.
The control signal sees to it that data communication takes place in a “disciplined” manner.
If a handshake is to be used, both parties to the communication must agree on it.
Network
AKA 245 and up to max. 123 addressable units together constitute a net work.
A connection between a gateway and a PC is an independent network.
A connection between a gateway and a modem is not an independent network.
The DANBUSS system is a combination of several networks. The individual net works are given
individual numbers. These numbers are entered in the DANBUSS system address. Network numbers
can only be assigned in the range 0 - 255.
Polling
A method of maintaining “law and order” in a data communication system.
One unit is nominated as master. This master will allow the other units time to communicate, one after
the other. In this way only one message will be routed through DANBUSS at a time.
Router
The part that ensures that datagrams will be received by the correct party.
In principle each unit in the DANBUSS system should contain a router function, but in certain cases
one in each network will suffi
ce.
The router uses a table for routing the datagrams.
Router table
A table containing information as to how the DANBUSS system is composed as well as a telephone
number at a modem gateway.
The system operator has to encode these tables.
System address
An address identifying each individual unit in a complete DANBUSS system comprising one or several
networks. The system address is composed of the network number and the address. It is written in the
NETWORK:ADDRESS mode (Net work:Address).
Example:
1:2 where 1 is the network and 2 the address.
2:115 where 2 is the network and 115 the address.
Terminology
AKA
245
Manual RS8DT102 © Danfoss 09/2004
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