C500BC061 Omron, C500BC061 Datasheet - Page 119

• Manufacturer Part Number: C500BC061
• Description: BACKPLANE
• Manufacturer: Omron

Specifications of C500BC061

• Leaded Process Compatible: No
• Peak Reflow Compatible (260 C): No
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Error Control
5-2
5-2-1
5-2-2
5-2-3
5-2-4
Error Control
Invalid Processing
Process Interruption
Time Monitoring
Retries
1, 2, 3... 1.
The host computer is responsible for ensuring system recovery after errors oc-
cur in the Host Link Unit.
The Host Link Unit runs the following checks to detect errors:
2.
3.
4.
5.
6.
Of the above commands, 1 to 3 are performed on a character by character basis.
Checks 4 to 6, however, are performed on each block (frame).
Transmit data in a multiple-link system is checked by means of a parity check
and a Frame Checksum (FCS). The FCS check is not performed in single-link
systems.
If the Host Link Unit detects an error in a single-frame command or the first frame
of a command block, it will regard the command as invalid. The command will not
be processed and, after the terminator is received, an error response will be sent
to the host computer. (For details of the error response, refer to 4-38 Response
Indicating an Unprocessed Command.
If the Host Link Unit detects an error in an intermediate frame, the commands up
to that point will be processed normally. Those following the erroneous frame,
however, will not be processed. After the Host Link Unit has received the termi-
nator of the erroneous block, it responds with a response code that informs the
host computer of the process interruption. (For details, refer to 4-45 Response
Code List.)
If the Host Link Unit does not receive a delimiter or terminator, it cannot send a
response to the host computer. Similarly, if the computer does not receive a deli-
miter or terminator, it cannot transmit further commands to the Host Link Unit. To
allow transmission to alternate smoothly between the computer and the Host
Link Unit, the process times need to be monitored. It is therefore necessary to
have a time-monitoring program on the host computer side. Its purpose is to initi-
ate remedial action if the right to transmit is not transferred quickly enough.
An error response will be returned to the originating device if the Host Link Unit
detects any communications line data that has been destroyed (e.g., by noise).
If, however, the Unit number has also been lost, no response will be made at all.
It is therefore necessary to have response monitoring and retry processing in the
host computer to check for error responses.
Parity check
Framing check
Overrun check
Format check
Entry data check (The start word, read word, etc., in the command format.)
Frame Checksum (An Exclusive OR check is performed on all command or
response data, from the unit number to the end of the text.)
Section 5-2
103