Marantz PD4292D Computer Monitor User Manual


 
50
Communication Format
Command 1
Unit ID 1
Unit ID 2
Command 2
Data length
Data
Check sum
Command 1
Command 1, along with command 2, is a number used to
distinguish each command.
In the case of ACK, when the lower order 4 bits is FH (as
in 3FH and 7FH), this indicates that the commands and
data of the supported equipment have been received. When
the lower order 4 bits is BH (as in 3BH and 7BH), this
indicates that unsupported commands and data have been
received.
Unit ID 1 and Unit ID 2
Unit ID 1 and unit ID 2 are numbers used to identify the
equipment that is to be connected.
60H is used for the plasma monitor and 80H is used for
external control equipment such as a personal computer.
1) Unit ID 1: Indicates the equipment sending the signal
2) Unit ID 2: Indicates the equipment receiving the signal
Command 2
Command 2, along with command 1, is a number used to
distinguish each command.
Check Sum (CKS), Error Processing, and ACK
1) The check sum described below and RS-232C odd
parity are used together for a check of the received data.
The check sum is the lower order 8 bits of one frame of
sent or received data comprising the sum total of
Command 1, Unit ID 1 and 2, Command 2, Data
Length, and Data.
Check Sum Example
DFH 80H 60H 47H 01H 01H 08H
Command 1 Unit ID 1 Unit ID 2 Command 2 Data Length Data Check Sum
Total 208H
2) Error Processing
When the communication interval is vacant for more
than 4 ms, thereafter a received Command 1 will be
recognized. If, at this time, meaningful data cannot
be recognized, that data will not be recognized (as
valid data).
An ACK will not be returned unless the receive data
error, the check sum error, and the receive data are
all taken in.
8 bit
8 bit 8 bit 8 bit 8 bit 8 bit 8 bit 8 bit
Plasma monitor
External equipment
e.g., Personal computer
Running Sense
Running Sense
Running Sense
Communications Flow
The plasma monitor regularly transmits a Running Sense
command at an interval of approximately 1 second.
(Running Sense command: 1FH 60H E0H 88H 00H E7H)
This command is used to recognize optional equipment.
The return of an ACK is not required when external equip-
ment such as a personal computer has been connected.
Note that destruction of this data is recommended when it
is taken in.
When various commands are to be sent from external equip-
ment such as a personal computer, the plasma monitor is
always receive enabled.
Note that when an ACK has not been returned from the
plasma monitor in 1.5 seconds, a resending of the com-
mand is recommended.
PD4292D-2 00.10.4, 3:11 PM50