Cutler-Hammer D320 PLC, User Manual

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Appendix C: COM2 UDCP Specification
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Configuration Flags
To support the three separate modes of operation for port 2 on the D320 CPU, the processor uses two
special internal Flags, F11 and F12. Individual bits in these flags set the mode of operation, trigger
communications, indicate status of communications, and configure the port parameters. Table 2 below
describes each flag bits function in the operation of the port.
Table 2 – Communications Flags
Flag Bit Function Description State Description
Flag Word F11
F11.0 Request Transmission 0: No operation 1: Start Transmission
F11.1 Indicates Transmission Failure 0: Normal 1: Transmission Error
F11.2 Enables the Start Code in ASCII mode 0: No Start Code 1: Start Code Enabled
F11.3 Enables the End Code in ASCII mode 0: No End Code 1: End Code Enabled
F11.4 Indicates that a message has been received 0: No message 1: Message Received
F11.5 Clears the Receive Buffer 0: Normal 1: Clear Receive Buffer
F11.6 Indicates a Port Overrun Failure 0: Normal 1: Overrun Error
F11.7 Indicates a Receive Failure (e.g. bad CRC) 0: Normal 1: Receive Error
F11.8 Enable Conversion of ASCII data to Binary 0: Enabled 1: Disabled
F11.9 Ignore Receive Errors 0: Signal Error 1: Ignore Error
F11.10 Enable Parity Setting 0: Disabled 1: Enabled
F11.11 Select ODD or EVEN Parity 0: ODD 1: EVEN
F11.12 Select the Number of Data Bits 0: 7 Bits 1: 8 Bits
F11.13 Select ASCII or Binary Communications 0: ASCII 1: Binary
F11.14 Reserved Do not use
F11.15 Enable Automatic CRC mode 0: Disabled 1: Enabled
Flag Word F12
F12.8 Enable User-Defined Communications (UD) 0: Disabled 1: Enabled
F12.9 Enable MODBUS RTU Communications
(MODBUS) 0: Disabled 1: Enabled