PDxx01
RS-232C Control Specification
Page: 5 / 49
Document Version [1.0]
Company Restricted
3. Communication Format
3-1.
Command1
Command 1, along with command 2, is a number used to distinguish each command.
Bit1, Bit0: 11B or 10B :Usually, a form
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.
3-2.
Unit ID1,2 (UA1,UA2)
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.
3-3.
Command 2
Command 2, along with command 1, is a number used to distinguish each command.
3-4.
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
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.
Command 1
Unit ID 1
Unit ID 2
Command 2
Data length
Data
Check sum
8bit
8bit
8bit
8bit
8bit
8bit
8bit
8bit
Total 208H
DFH 80H 60H 47H 01H 01H 08H
Command1 Unit ID1 Unit ID2 Command2 Data Length Data Check Sum
