Mitsubishi Melsec-L Series User Manual page 316

Symptom
• When the predefined
protocol is executed,
the "ERR." LED turns
on.
15 - 47
Cause
• The user-edited protocol
setting in the predefined
protocol support function
of GX Works2 is
inconsistent with the
packet format of the
external device.
• An expected packet was
not received, and a
monitoring timeout error
occurred.
• A communication error
occurs.
REMARKS
When the "ERR." LED is turned on, an error code is stored in the following buffer
memory.
Error cause
Switch setting error
Mode switching error
On-demand execution error
Data transmission error
Data receive error
Modern function error
MC protocol transmission error
Monitoring device error
Predefined protocol function error
For details of the error codes, refer to Section 15.2.
Corrective action
• Check the packet format of the external
device, and correct the protocol setting.
(1) When a conversion variable exists in the
receive packet, check for an error in the
setting of Conversion, Sign character,
Number of decimals, Delimiter, or Number
of digits.
(2) When an error check code exists in the
receive packet, check for an error in the
setting of Processing method, Code type,
Data length, Data flow, Complement
calculation, or Calculating range.
(3) When Length exists in the receive packet
and a conversion variable is included in the
calculating range of the Length, check for
an error in Code type, Data length, Data
flow, or Calculating range set for the
Length.
• Using the circuit trace (communication data
monitoring function) of the predefined
protocol support function of GX Works2,
check for the data being transmitted from
the external device.
• Confirm the error by the system monitor,
and remove the cause of the error.
Error code storage buffer memory
Address
CH1 CH2
203
H
256 266
H H
257 267
H H
258 268
H H
221
H
25A 26A
H H
2205 2305
H H
4042 4052
H H
15 TROUBLESHOOTING
Name
Switch setting error and mode switching
error status
On-demand execution result
Data transmission result
Data reception result
Modern function error code
MC protocol transmission error code
Programmable controller CPU monitoring
function execution result
Predefined protocol function error code
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