Cutler-Hammer D320 PLC, User Manual

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Appendix C: COM2 UDCP Specification
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F11.4 MESSAGE RECEIVED
UDCP Mode. When the CPU has successfully received a complete message, this flag is set to indicate
to the user program that a new message is available in the Receive Data Buffer (SR334-SR369). This
flag is reset by the CPU after the Clear Buffer Flag (F11.5) is set to indicate that the data has been read
by the program. Until this flag is reset, no new data can be received.
F11.5 CLEAR RECEIVE BUFFER
UDCP Mode. This flag is set by the user program to indicate to the CPU that the received data has
been read. When this flag is set, the Message Received Flag (F11.4) is reset, and the data is cleared
from the Receive Data Buffer (SR334-SR369).
F11.6 PORT OVERRUN ERROR
When an error occurs on the Receive port (e.g. more than 72 bytes are received), this flag is set to
signal that an overrun error has occurred. The flag will remain set until the user program clears it.
F11.7 RECEIVE FAILURE
This flag is set whenever an error occurs in the received message (e.g. bad CRC, wrong baud rate,
etc.). The flag will remain set until the user program clears it.
F11.8 ENABLE ASCII BINARY CONVERSION
UDCP Mode. When this flag is set by the user program, incoming ASCII text values are automatically
converted to their binary values. For example, if the hex word value $3130 is received, the equivalent
ASCII characters are “10”. The ASCII
Binary conversion will convert this ASCII data automatically
into a single byte value of 10 when it is received.
F11.9 IGNORE RECEIVE ERRORS
UDCP Mode. This flag is set by the user program. Setting this flag disables the detection of Receive
errors. All data is received as is, and the Receive Error Flags (F11.6, F11.7) are ignored.
F11.10 ENABLE PARITY
The communications port is capable of being configured for three types of parity checking on
transmitted and received messages; odd, even, and none. When this flag is turned Off, the parity is set
to None. When this flag is set by the user program, the parity is determined by the Select Parity Flag
(F11.11).
F11.11 SELECT PARITY
This flag sets the parity for communications when the Enable Parity Flag (F11.10) is turned On. When
this flag is On, Even parity is used. When it is Off, Odd parity is used.
F11.12 SELECT DATA BITS
This flag sets the data bit size for communications. When it is Off, 7 bit communications is used.
When it is On, 8 bit communications is enabled.
F11.13 SELECT ASCII/BINARY
UDCP Mode. In the User-Defined Communications mode, the messages can be transmitted and
received in either ASCII mode, or binary mode. This flag sets which mode will be used. When the
flag is set, all communications are in binary. Otherwise, ASCII communications is assumed.