105BCommunication processor
12.3 Point-to-Point (PtP) communication
S7-1200 Programmable controller
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System Manual, 11/2011, A5E02486680-05
Network 3: Enable the SEND_PTP instruction when the M20.0 flag is set. Also use this flag
to set the REQ input to TRUE for one scan. The REQ input tells the SEND_PTP instruction
that a new request is to be transmitted. The REQ input must only be set to TRUE for one
execution of SEND_PTP. The SEND_PTP instruction is executed every scan until the
transmit completes. The transmit is complete when the last byte of the message has been
transmitted from the CM 1241. When the transmit is complete, the DONE output (Tag_5 at
M10.0) is set TRUE for one execution of SEND_PTP.
Network 4: monitor the DONE output of SEND_PTP and reset the transmit flag (Tag_8 at
M20.0) when the transmit operation is complete. When the transmit flag is reset, the
RCV_PTP instruction in Network 1 is enabled to receive the next message.
12.3.5.3
Configuring the terminal emulator
You must set up the terminal emulator to support the example program. You can use most
any terminal emulator on your PC, such as HyperTerminal. Make sure that the terminal
emulator is in the disconnected mode before editing the settings as follows:
1.
Set the terminal emulator to use the RS232 port on the PC (normally COM1).
2.
Configure the port for 9600 baud, 8 data bits, no parity (none), 1 stop bit and no flow
control.
3.
Change the settings of the terminal emulator to emulate an ANSI terminal.
4.
Configure the terminal emulator ASCII setup to send a line feed after every line (after the
user presses the Enter key).
5.
Echo the characters locally so that the terminal emulator displays what is typed.