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
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
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 |
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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.
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