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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 su
m
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