IDEC FC6A-C16K1CE Communications Manual page 162

7: D L C
ATA INK OMMUNICATION
Special Data Registers for Data Link Communication Error
In addition to data registers assigned for data communication, the master station has 31 special data registers and each slave
station has one special data register to store data link communication error codes. If any communication error occurs in the data
link system, communication error codes are set to a corresponding data register for link communication error at the master station
and to data register D8069 at the slave station. For details of link communication error codes, see below.
If a communication error occurs in the data link communication system, the data is resent two times. If the error still exists after
three attempts, then the error code is set to the data registers for data link communication error. Since the error code is not
communicated between the master and slave stations, error codes must be cleared individually.
Master Station
Special Data
Data Link Communication Error Data
Register
D8069 Slave station 1 communication error
D8070 Slave station 2 communication error
D8071 Slave station 3 communication error
D8072 Slave station 4 communication error
D8073 Slave station 5 communication error
D8074 Slave station 6 communication error
D8075 Slave station 7 communication error
D8076 Slave station 8 communication error
D8077 Slave station 9 communication error
D8078 Slave station 10 communication error
D8079 Slave station 11 communication error
D8080 Slave station 12 communication error
D8081 Slave station 13 communication error
D8082 Slave station 14 communication error
D8083 Slave station 15 communication error
D8084 Slave station 16 communication error
If any slave stations are not connected, master station data registers which are assigned to the vacant slave stations can be used
as ordinary data registers.
Slave Station
Special Data Register
D8069
Note: Slave station data registers D8070 through D8099 can be used as ordinary data registers.
Data Link Communication Error Code
When an error occurs during the data link, the data is sent again (the operation is retried) up to twice.
If an error occurs on the third attempt to send the data, the error number is set in the data register for the communication status/
error of the master station and the corresponding slave station.
Error Code
1h (1)
2h (2)
4h (4)
8h (8)
10h (16)
20h (32)
40h (64)
When more than one error is detected in the data link system, the total of error codes is indicated. For example, when framing
error (error code 2h) and BCC error (error code 10h) are found, error code 12h (18) is stored.
7-4
Data Link Communication Error Data
Slave station communication error
Overrun error (data is received when the receive data registers are full)
Framing error (failure to detect start or stop bit)
Parity error (an error was found by the parity check)
Receive timeout (line disconnection)
BCC (block check character) error (disparity with data received up to BCC)
Retry cycle over (error occurred in all 3 trials of communication)
I/O definition quantity error (discrepancy of transmit/receive station number or data quantity)
FC6A S M S A
ERIES ICRO MART
Special Data
Register
D8085
D8086
D8087
D8088
D8089
D8090
D8091
D8092
D8093
D8094
D8095
D8096
D8097
D8098
D8099
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Error Details
- -O T C
LL IN NE YPE OMMUNICATION
Data Link Communication Error Data
Slave station 17 communication error
Slave station 18 communication error
Slave station 19 communication error
Slave station 20 communication error
Slave station 21 communication error
Slave station 22 communication error
Slave station 23 communication error
Slave station 24 communication error
Slave station 25 communication error
Slave station 26 communication error
Slave station 27 communication error
Slave station 28 communication error
Slave station 29 communication error
Slave station 30 communication error
Slave station 31 communication error
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M FC9Y-B1730
ANUAL