Configuration and startup
3886_en_A
PHOENIX CONTACT
23
The GW PN/ASCII... modules can be configured to detect serial packet delimiters used for
the identification of a raw data packet.
3.7.1.2
Raw/ASCII serial packet delimiters
“Detect Delimiters from Serial Device”:
Figure 3-10
“Raw/ASCII Serial Packet Delimiiters” dialog box
Start transmission (STX)
: When enabled, GW PN/ASCII... detects an STX (start of
transmission) byte sequence which is configured as
one byte
or
two bytes
when it
receives a serial packet. If
none
is selected, the GW PN/ASCII... accepts the first byte
received after the last End Transmission (ETX) byte(s) as the start of the next data packet.
If
one byte
is selected, the GW PN/ASCII... starts to collect data when the STX byte is
detected. If the first byte is not the STX byte, it discards the byte. The GW PN/ASCII...
continues to discard the bytes until it finds an STX byte. If
two bytes
is selected, the
GW PN/ASCII... starts to collect data when both of the STX bytes are detected. If the STX
bytes cannot be found, it discards the bytes. The GW PN/ASCII... continues to discard the
bytes until it finds the two STX bytes.
–
Byte 1:
Specifies the character that represents the first STX byte. The GW PN/ASCII...
looks for this character in the first STX byte, if the length is one byte or two bytes.
Specify a value between
0
and
FF
in hexadecimal format.
–
Byte 2:
Specifies the character that represents the second STX byte. The
GW PN/ASCII... looks for this character in the second STX byte, only if the length is two
bytes. Specify a value between
0
and
FF
in hexadecimal format.
End transmission (ETX):
When enabled, the GW PN/ASCII... detects an ETX (end of
transmission) byte sequence that is configured as
one byte
or
two bytes
marking the end
of the serial packet. The length indicates the number of ETX bytes; if
none
is selected, this
function is disabled and the GW PN/ASCII... uses the Rx Timeout Between Packets to
indicate the end of data packet. If
one byte
is selected, the serial data is checked for one
ETX byte to identify the end of a serial packet. If
two bytes
is selected, the serial data is
checked for two ETX bytes to identify the end of a serial packet.
–
Byte 1:
Specifies the character that represents the first ETX byte. The GW PN/ASCII...
looks for this character in the first ETX byte, if the length is one byte or two bytes.
Specify a value between
0
and
FF
in hexadecimal format.
–
Byte 2:
Specifies the character that represents the second ETX byte. The
GW PN/ASCII... looks for this character in the second ETX byte, only if the length is two
bytes. Specify a value between
0
and
FF
in hexadecimal format.
Strip RX STX/ETX Chars:
When enabled, the STX and ETX characters are removed from
the received serial packets. Packets sent from the PLC by way of Ethernet to the serial ports
of the GW PN/ASCII... are not checked for STX/ETX characters.
The GW PN/ASCII... modules can also be configured to append characters to the
beginning or end of a serial packet.
Similar information is then entered under “Append Delimiters from PLC” in the same group:
