BSWA 308 - Recovery from Transmission Errors

BSWA 308/309 BSWA Technology Co., Ltd
61
Where: ATTR=’A’.
If more than one response data, each data should be separated by a comma ‘,’.
(3) Normal Response: sent by the sound level meter.
<STX>
ID
ATTR
<ETX>
BCC
<CR>
<LF>
1
1
1
1
1
1
1
Where: ATTR=<ACK>。
(4) Error Response: sent by the sound level meter
<STX>
ID
ATTR
Error code
<ETX>
BCC
<CR>
<LF>
1
1
1
4
1
1
1
1
Where: ATTR=<NAK>.
The error code occupies 4 bytes. All possible error code is listed in the following table. The
meaning of error code is described in section 5.2.6.
Error Code
Meaning
0001H
Instruction Error
0002H
Parameter Error
0003H
Unavailable on the Current State
5.2.6 Recovery from Transmission Errors
Various errors may occur when transfer the command block or response block. The following
describe how the sound level meter will deal with and restore to the initial state when an error
occurs.
(1) Block Transfer Not Complete
Section 5.2.5 describes the 4 kinds of block transmission format. When the sound level meter
receives the beginning of a block of characters <STX>, it will continue to receive the
remaining data until the end of the block <CR>, <LF>. When the data reception is complete
and correct parity, the sound level meter will conduct follow-up actions. If received the
character <STX> again before <CR>, <LF>, the sound level meter will ignore all the
information previously received and re-start the reception of a block.
(2) Validation Failure
After receiving the data block, sound level meter will verify it (except when BCC=00H). When
validation fails, the sound level meter will ignore this instruction.
Byte
Byte