Error codes
Name
(hexadecimal)
7D21H
Decimal point
place
specification
error
ASCII BIN
7F20H
conversion
error
7F24H
Sum check
error
7F67H
Overrun error
7F68H
Framing error
7F69H
Parity error
7F6AH
Buffer full error
7FF2H
Predefined
protocol setting
error
6 PREDEFINED PROTOCOL SUPPORT FUNCTION
202
6.9 Troubleshooting
Description of error
• An out-of-range decimal point position is set when the
number of decimals is set to variable point.
• The number of decimals is larger than the number of digits
for each data.
• When data is received by conversion variable, the data
corresponding to the conversion variable cannot be
converted to binary numbers.
• When data is received using a protocol including a packet
of check code (ASCII hexadecimal or ASCII decimal), the
data corresponding to the check code cannot be converted
to binary numbers.
• The received sum check does not match with the calculated
sum check.
• The received horizontal parity code does not match with the
calculated horizontal parity code.
• The received check code does not match with the
calculated check code.
The following data was received before the CPU module
completes receiving process.
• The stop bit settings do not match.
• A disturbance occurred in the line due to power supply ON/
OFF of the target station.
• There is noise on the line.
• In the multi drop connection, data is sent simultaneously
from multiple devices.
• The parity bit settings do not match.
• A disturbance occurred in the line due to power supply ON/
OFF of the target station.
• There is noise on the line.
• In the multi drop connection, data is sent simultaneously
from multiple devices.
The receive buffer overflowed and received data was skipped.
The instruction cannot be executed with the current
predefined protocol setting.
Error handling
• Check the set decimal point position.
• Check the number of digits setting, and set the
decimal point position so that the number of decimals
is less than the number of digits.
• Check the sent message of the counterpart device,
modify it if necessary, and then execute
communication again.
• If the protocol was edited, check the packet format of
the counterpart device to check that the set values of
the conversion, sign character, number of decimals,
delimiter, and number of digit for conversion variable
are correct.
• If the protocol was edited, check the packet format of
the counterpart device to check that the setting for
the code type and data length of check code are
correct.
• Check the sum check of the counterpart device.
• Check the horizontal parity code of the counterpart
device.
• Check CRC-16 of the counterpart device.
■If the protocol was edited, check if the following
values match the packet format of the counterpart
device:
• Processing method or code type of the check code
• Data length
• Data flow
• Complement calculation
• Calculating range
• Reduce the communication speed and then execute
communication again.
• Check if momentary power failure has occurred on
the station with the CPU module (using the special
register SD1005). If momentary power failure has
occurred, remove the cause.
• Match the settings of the CPU module with that of the
counterpart device.
• Take measures against noise.
• In the multi drop connection, insert an interlock so
that data is not sent simultaneously from multiple
devices.
Perform a predefined protocol including data reception
to clear the receive buffer.
Correct the setting value of the predefined protocol.