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4.1.2 Cabling of Hermes DXD (number of devices > 20)
If there are more than 20 devices a distribution panel has to be used. Then the cabling looks like this:
Figure 4-3
remote control cabling by use of a distriubtion panel
Remote control cabling is available in various length and with adapters for connecting to different de-
vices. See section
7.3.2 Remote Control
for the parts list, please!
4.2 Definit ion of Protocol
4.2.1 Connec tion Settings
The physical medium for data transfer is based on a RS-232-C interface:
signal level RS-232-C
baud rate 9,600 baud
data bits 8
parity bits none
stop bits 1
max. distance 25 meters between two active members (
RCS
or
RCM
)
Table 4-1
4.2.2 Commu nication
The devices of H
ERMES
DXD are numbered consecutively. A certain device is addressed by means of
this number. H
ERMES
DXD executes the received command and passes on the message until the re-
quested device receives the command. The command returns unprocessed to the
RCM
if no H
ERMES
DXD has been addressed.
In case a device has been addressed, and the command is valid, the command is executed, and the de-
vice sends an acknowledge ACK to the master.
In case a device has been addressed, and the command is invalid, the device passes the command un-
processed to the master and adds "
EP
" (
Error Protocol
) to the command.
Basically there are two kind of commands: commands which are answered by an acknowledge includ-
ing a status information and commands which are passed on or answered without status.