Programmers User Manual

8
3. Communication Format
3.1 Signal Format
RS-232C Conformity Connector & Pin assignment of connector are referred to 2.2
Transmission Mode : Half Duplex (Full duplex for notification)
Transfer Speed : 4800, 9600, 14400, 19200bps. (selected through menu window)
Data Bit : 8 bit
Parity : None
Stop Bit : 1 bit or 2 bit (selected through menu window)
Handshake : RTS/CTS Control
Others : One Acknowledge per command
RS-232C level Definitions
ON : +5V to +15V
OFF : –5V to –15V
3.2 Understanding
The followings are described based on the signal from the computer terminal (RS-232C).
• The flow is controlled by RTS/CTS terminal control.
• When the VC-C50i is ready to receive control commands, the CTS line of the computer is ON.
And as long as VC-C50i is turned on, the CTS line is always ON because VC-C50i is ready to
receive the control commands.
• In case of starting the communication from the computer, the RTS line of computer must be
ON.
• After receiving the answer corresponding to the control command, the next control commands
will be ready to transmit.
Before transmitting the answer corresponding to the control command, VC-C50i cancels the
received code, in case of receiving the next control commands.
• In case of not receiving the answer to the computer, the RTS line of the computer must be OFF.
In this case, VC-C50i will suspend to issue the answer. If VC-C50i, however, suspends more than
one second, the issue of the answer will be forced to stop and VC-C50i returns to the receiving
status.
• In case of using the notification functions, the communication format must correspond to full
duplex. There are some cases for VC-C50i to issue the notification data, while the computer
issues the commands.
• The standard waiting time of the answer is 300ms. If VC-C50i does not return the answer more
than 300ms, there must be some errors.
• Note that VC-C50i is unable to execute remote control and communication control at a one time.
After turn on, VC-C50i is under the condition of remote control. If the communication control is
required, Host Control Mode command or Cascade ON command must be issued. Note that
the VC-C50i can not shift the remote control status to the host communication control mode
during menu processing.