ICP DAS USA I-7521, Руководство пользователя

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I-7521/I-7522/I-7522A/I-7523/I-7524/I-7527 User’s Manual,Ver2.5 Aug.2015
108
5.3.30 $AAU

Description :
This function reads data from the RS-232 COM port buffer.
There is 1Kb queue buffer for its local RS-232 device. All input data from RS-232 COM
port can be stored in the queue buffer until the Host PC has time to read it. These features
allow the Host PC to be linked to thousands of RS-232 devices without any loss of data.
Any RS-232 device should obey the rules of the request-reply protocol. In other words,
RS-232 devices are passive. If they do not receive any commands, they will not send
any messages out. However, since active devices are frequently developed, ICPDAS
controllers are designed with a buffer to receive these messages in situations such as
this.
Buffer operation rules:
Rule 1: The buffer is enabled after being powered-on.
Rule 2: The (delimiter) AA command (Refer to Sec.5.3.10) disables the buffer operation
for that port
Rule 3: After disabling the buffer, the controller will wait for X seconds (=timeout1, refer
to Sec.5.3.33) for a response from the RS-232 device. The response will then be
transfered to COM2. If no message is received, the buffer will be re-enabled.

Syntax :
$AAU[chk](CrLf)
$
Delimiter character
AA 2-character module address in HEX format. The valid range is from
00 to FF
[chk] 2-character checksum. If the checksum is disabled

no [chk]
(CrLf) End Character

Response : valid command

(data)[chk](CrLf)
invalid command

?AA[chk](CrLf)
no response

The buffer is empty, syntax error or communication error, or
address error
! Delimiter character indicating a valid command
? Delimiter character indicating an invalid command
AA 2-character module address in HEX format
[chk] 2-character checksum. If the checksum is disabled

no [chk]
(CrLf) End Character

Example:
Command: $01U(CrLf)
Response: data1(CrLf)
Command: $01U(CrLf)
Response: data2
Command: $02U(CrLf)
Response:
Retrieves another data: “data2” from the
buffer of the port that is addressed 01
No data in the buffer of the port that is
addressed 02
Retrieves “data1” from the buffer of the
port that is addressed 01
For: I-7521/I-7522/I-7522A/I-7523/I-7524/I-7527