How Signals Are Passed
I/O-Bus operates with the master passing signals over a remote bus cable to each slave device in series. The slaves return signals to the master over the same cable.
How Data Is Transferred
The I/O-Bus functions as a logical shift register. The entire data stream of the application, originating at the master, is transferred serially from slave to slave down the remote bus. Each slave regenerates the entire stream before passing it to the next slave in the ring. As a slave handles the stream data, it extracts the portion that is assigned to it and adds any output data to the stream.
Transmission Speed
Data is transmitted at the baud rate of 500 kbits/s.
Amount of Data
The 171 CBU 78090, 171 CBU 98090 and 171 CBU 98091 processors support the following number of 16-bit words in the data stream:
Word type |
Maximum number |
Input words |
256 |
Output words |
256 |