22.11.3.1 Label Settings
Control
This control variable is used to clear the
Send buffer, Receive buffer, and error status. This control
variable is write-only.
When designating a bit
[c:EXT_SIO_CTRL**](**:00 to 15)
When designating a word [c:EXT_SIO_CTRL]
Example expression:
When designating a bit [c:EXT_SIO_CTRL00] =
1
When designating a word [c:EXT_SIO_CTRL]=
0x0007
Contents of EXT_SIO_CTRL
-
When a word is selected, and two or more bits
are set simultaneously, the processing is executed in the following
order.
Clear error → Clear receive buffer → Clear send buffer
-
Clear error clears the value in status bits 1
(send error) and 3 (receive error).
Status
Status includes the following
information.
This status variable is write-only.
When designating a bit
[c:EXT_SIO_STAT**](**:00 to 15)
When designating a word [s:EXT_SIO_STAT]
Example expression:
When designating bit if([s:EXT_SIO_STAT00] == 1)
When designating word if(([s:EXT_SIO_STAT] & 0x0001)
<> 0)
Contents of EXT_SIO_STAT
-
The reserved bits may be assigned in the
future. Therefore, be sure to check only the necessary bits.
-
Two types of transmission errors exist: the
transmission timeout error and the transmission buffer-full error.
When either of the two errors occurs, the transmission error bit
turns ON. The transmission timeout period is five seconds.
-
There are four types of receive errors: parity
error, overrun error, framing error, and overflow. When one of
these four errors occurs, the bit for the receive error turns
ON.
-
If a transmission error is detected, the send
data remains in the transmission buffer. If a transmission error
cannot be detected, the send data is sent from the transmission
buffer.
-
When using the serial interface COM2, which is
RS-422, the CS (CTS) signal cannot be detected. As a result,
disconnection of a cable cannot be detected.
Received Data Size
Shows the quantity of data (number of bytes)
received at that time. The received data size is read-only.
[r:EXT_SIO_RECV]
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