Appendix C, Rs3 Daisy Chaining 8; About The Protocol 8; Address Modes 8; Auto Address Mode 8 - Projectiondesign cineo Supplementary Manual

APPENDIX C, RS3 DAISY-CHAINING
C.1 About the protocol
The projectors can be daisy-chained and controlled independently by adding address
information to the original 32 byte binary RS232 message.
Figure 1: RS232 Daisy-Chaining
Figure 1 shows how to daisy-chain several projectors. The control system is connected
to RS232 IN (female) in projector 1. The projector 1 RS232 OUT (male) is connected to
projector 2 IN, and so on. Max numbers of projectors in a chain are 255.
To independently address and control each projector in the chain, the original 32-bytes
protocol is extended with address information. The header size is increased from 7 to 8
bytes and the total packet is increased from 32 to 33 bytes. The acknowledge packet size
is increased from 33 to 34 bytes.
Table 3 shows the original non-address 32-bytes message.
1 2 3 4
packet payload
magic number
type size lo
0xBE 0xEF
Table 3: 32-bytes non-address message
1 2 3 4
address magic packet
address
number type
0x00-
0xBA 0xDA
0xFF
Table 4: 33-bytes address message
Legal message address range is 0-255, where 0 is broadcast address.
5 6 7 8-32
payload
CRC lo CRC hi payload
size hi
5 6 7 8
pay-
payload
load CRC lo CRC hi payload
size lo
size hi
Table 5 shows the 34 bytes acknowledge message with address information. As for the
non-address message, the acknowledge message consist of a PAK (0x1E) followed by
the initial message sent from the host.
1 2 3
address magic
PAK
number dress
0x00-
0x1E 0xBA 0xDA
0xFF
Table 5: 34-bytes acknowledge address message
C. Address modes
Two different addressing mechanisms are available, auto and fixed. The default mode is
auto-addressing. It is important that all projectors in the chain are set to the same ad-
dress mode. The address mode must be set from the projector's menu system.
NOTE! The original 32-bytes non-address binary protocol does not support addressing,
and commands using this protocol will only be executed by the first projector in the chain.
C..1 Auto address mode
In auto address mode, the address of the projector is based on its physical position in the
chain. The first projector has address 1, the second has address 2 and so on.
C.. Fixed address mode
In fixed mode, each projector needs to be programmed with a unique fixed address ir-
respective of its position in the chain. The address must be specified for each projector by
setting it from the projector's menu system. If two or more projectors are equipped with
the same address, then only one of the projectors will respond to a message addressed
to that actual address.
Legal projector address range is 1 to 255 (0x01 – 0xFF).
C..3

Broadcast

Address 0 (zero) is broadcast address. A broadcast message is sent to all projectors
9-33
in the chain regardless of the address mode. When a projector receives a broadcast
message it will execute the command and send the message to the next projector in the
chain. No acknowledge message will be sent in reply to a broadcast message.
C.3 Baud rate
The baud rate is configurable between 4800, 9600 and 19200. Default baud rate is
19200. If there are several projectors in the chain (>10) or high RS232 traffic it is strongly
recommended that the baud rate is reduced to 4800. This will reduce the processing load
at the first projectors in the chain.
4 5 6 7 8
ad- type of pay- pay-
CRC lo
msg load lo load hi
9 10-34
pay-
CRC hi
load
9