Vidikron VP-42HD, VP-60 Communication Format, External Controls, Command, Unit ID 1 and Unit ID

External Controls

Communication Format

8 bit 8 bit 8 bit 8 bit 8 bit 8 bit • • 8 bit 8 bit

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 80 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
Com-	Unit	Unit	Com-	Data	Data	Check
mand 1	ID 1	ID 2	mand 2	Length		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.