Panasonic PV-500, Руководство пользователя

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9.2.2 Details of Commands
“SEND” described in this chapter indicates the commands given from external devices to PV500. On the other
hand, “Receive” indicates the responses for the sent commands from PV500 to external devices.
About Block Check Code(BCC)
All command messages are added with a block check code, which checks an error using horizontal parity to
improve reliability of transmission data. This manual describes a block check code as “BBC”.
As a block check code of PV500, a code that is given by removing a terminal code from Exclusive OR (8-bit) of
a command message and converting it into ASCII code (two letters) is used.
If you do not employ block check, add it to “**” (2AH2AH) instead of a block check code.
Example) When reading execution time
Command message
% P R S Y S _ T I M E 1
25H 50H 52H 20H 53H 59H 53H 5FH 54H 49H 4DH 45H 31H
Obtain Exclusive OR
25H
Command message including BBC
% P R S Y S _ T I M E 1 2 5 CR
BCC
About Response at Error
When sending a command message from the external device, an error response message containing 3-digit
error code may be returned. This message is returned when the sent command is wrong or PV500 cannot
receive the command.
The response differs depending on commands except the following common responses. Refer to the
descriptions of each command.
Error Response Message Common to Commands
% ! 1 0 0 BCC CR
•
This message is sent when Block Check Code (BCC) error occurred or an undefined command
(unrecognizable command) is received.
•
ERROR 1 signal turns on.
% ! 1 1 0 BCC CR
•
Receive buffer overflow of PV500. This might occur when inputting multiple commands in a row from
the external device to PV500. If you receive this error response, decrease commands to send to
PV500.
•
ERROR 1 signal turns on.