Host Computer System.pdf - 第16页
AVK3 HOST COMPUTER SYSTEM 1.2 PanaPr otocol and Comm and Specifi cations D77HEC-51- 020-A0 1.2- 3 If t he check sum is not nec ess ary bec ause of maki ng t h e sof tware for the hos t comput er, leav e t he m ess age f …
AVK3
HOST COMPUTER SYSTEM
1.2 PanaProtocol and Command Specifications
D77HEC-51-020-A0
1.2-2
Command field
The message between AVK3 and the host computer is conducted by the specified command.
The command is largely categorized as follows and is processed by ASCII code.
The large category is actually limited to the following 4 types and used as follows:
Large
category
command
Message Contents How it is used
A Acknowledge
Used when AVK3 and host computer
mutually confirm that the message
has been received.
(Host CPU ← → AVK3)
Used as communication procedure,
for use in “acknowledgment”,
“negative acknowledgment” and
“request to resend” to the message
received.
C
Control
command
Used when the host computer
requests action to AVK3.
(Host CPU → AVK3)
Start of sending and receiving NC
program.
Specifies I/O monitoring.
Start/stop/reset command for
machine.
D Data
Means the data transmitted between
AVK3 and host computer.
(Host CPU ← → AVK3)
Transmits NC program.
Transmits the results of I/O
monitoring.
R
Real time
information
Used for AVK3 to inform host
computer of changes in information
whenever they occur.
(Host CPU ← AVK3)
“Operation mode information”,
“Error information” and “Recovery
information” are transmitted from
AVK3 on real time to Host
computer. The host computer
compiles and analyzes this
information and uses it for
production management of AVK3.
Data field
As explained above, the actual number range of data usable is 88 or less. In the data field, the
characters other than those specified by command are neglected. Also, all are processed by ASCII
code.
Check sum
The ASCII code, “number of characters”, “Command field” and “Data field” are subtracted by 8 bits not
counting zero, and the results are divided into 4 bits each of upper and lower digits. They are
respectively expressed in hexadecimals (X‘0’ - F”) and processed by ASCII code.
Therefore, at the time of confirmation of check sum, add command and data in ASCII code (7 bits, no
parity) to check sum data. If the total of 8-bit sum becomes zero, the check sum is OK.
To figure out the character position of check sum, do not figure the 2-digit character before ETX. But,
with the number of characters as the base, count the number of the data fields, and a 2-digit character
after the contents of the count should coincide with the number of characters. Therefore, if there is an
error in the number of characters, an error occurs in the check sum, too.
C 1
Small category (character used: 0-F)
Large category (character used: A-Z)
AVK3
HOST COMPUTER SYSTEM
1.2 PanaProtocol and Command Specifications
D77HEC-51-020-A0
1.2-3
If the check sum is not necessary because of making the software for the host computer, leave the
message format as it is and substitute a dummy data in the check sum column and then select
changeover switch. All the check sums in the machine will all be OK.
ETX (END OF TEXT)
The ETX which appears at the end of the message is to complete the message which started with STX.
In ASCII code with parity, it becomes X’03’.
Break (Optional)
When a conversation takes place between a machine and the host computer, several messages are
exchanged between the two according to commands. A break code is used to start a conversation
from a machine to the host computer, and is output to the host computer only once at the start of the
conversation.
This is the code that SD terminal of the RS-232C interface is clamped forcefully to signal level “1” by
1.5-digit character, and this is usually used on the mini-computer to lead the data which is sent by
breaking the current job.
When this is not necessary for the convenience of the host computer, select changeover switch of
checksum function to cut the break. Never add this to the machine. This is not output in the standard
settings.
Start
End
A break code is attached
only this time.
No break code
Host
computer
AVK3
No break code
No break code
AVK3
HOST COMPUTER SYSTEM
1.2 PanaProtocol and Command Specifications
D77HEC-51-020-A0
1.2-4