Yamaha RCX40, User Manual

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RS-232C interface
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3. Communication specifications
3.4 Other caution items
1) The controller allows receiving data as long as the receive buffer has a free area.
The receive buffer is cleared in the following cases.
• When the power was turned off and turned back on.
• When the program was reset.
• When an ONLINE statement or OFFLINE statement was executed according to the
robot language.
• When the communication parameter was changed in “SYSTEM” mode or when
initialization was executed.
2) When an external device is turned on, it might send incorrect data to the robot
controller. While the robot controller becomes ready to receive data as soon as the
power is turned on, so the incorrect data may be stored in the receive buffer if the
controller is turned on prior to the external device, causing a communication error.
In such a case,
• Reset the program before program execution.
• Clear the receive buffer by placing an ONLINE statement or OFFLINE statement at
the top of the program.
• Turn the external device on before turning the controller on.
3) When the external device does not support handshake protocols (BUSY control,
XON/XOFF control), the data processing speed becomes slower than the
communication speed, causing a communication error. In this case, take
countermeasures such as by reducing the communication speed (baud rate).
4) When the communication speed is set at a high rate, communication errors may
occur due to external noise or other factors. In this case, take countermeasures such
as by reducing the communication speed.
5) There is no response to external transmission during direct command execution or
point trace execution in “AUTO” mode. A response occurs after execution.