KUNBUS-COM EtherCAT
31 / 135
4.7 SDI - Serial Data Interface
The serial data interface allows the application to access the
individual Memory Register via the Modbus-RTU protocol. This
allows you to configure the COMS-Modul automatically and to write
productive data in the input registers or to read it from the output
registers.
The serial data interface is located at the application interface. The
respective cables are provided there with 3.3 V logic levels. To
connect these cables, you have the following options:
– Connect the cables directly with the UART inputs of the microprocessor
on the main board
– Convert the cables to standardised levels using level converters or
interface ICs. Afterwards, place the converted levels onto connectors for
connecting a PC or terminal.
We deliver the Modul to you with the following default settings to
enable access via the SDI :
• automatic baudrate detection
• 8 data bits
• 1 stop bit
• Even parity (Even)
Automatic bitrate detection means that the module tests the following
bitrates until it has received a correct Modbus-RTU telegram:
• 2400 bit/s
• 4800 bit/s
• 9600 bit/s
• 19200 bit/s
• 38400 bit/s
• 57600 bit/s
• 115200 bit/s
NOTICE! During automatic bitrate detection the module does not
send a reply to the master until the correct bitrate has been
detected. This procedure can require up to 40 polls of the
master.
TIP: Set a fixed bitrate if the automatic bitrate detection lasts too
long for you.
You can make the settings optionally using theCDI [
}
96] or in
thememory register 0x0005 [
}
54].
Components
