Checking Sequence Program; Checking The Communication Setting; Checking Error Codes - Mitsubishi MELSEC iQ-F FX5 User Manual

Checking sequence program

An error may occur when a serial port using MC protocol is specified in a command that will be used in inverter
communication, non-protocol communication or predefined protocol support function. (Page 236 Combined Use of Serial
Communication)

Checking the communication setting

Verify that protocol type is "MC Protocol". When the protocol type is not "MC Protocol", communication will not function
correctly. (Page 79 Communication Setting)
After changing any parameters, make sure to turn OFF→ON the PLC power, or reset.

Checking error codes

3C/4C frame
■Error codes when NAK is sent
The table below shows error codes (hexadecimal) and contents of errors when NAK is sent in communication between the
counterpart equipment and a CPU module.
When two or more errors occur at the same time, priority is given to the error code with the smallest number, and the error
code with the smallest number is sent. Further, in case of an occurrence of the following errors, initialize the entire
transmission sequence.
Error Error item Description of error
code
(hexadeci
mal)

4000H to An error detected by the CPU unit.
4FFFH (An error occurring outside communication by MC
protocol)
7143H Device number Head device address is outside the range.
error
7164H Request There is an error in the request contents or the device
contents error specification method.
7167H Disabled in RUN Write command is specified when write not possible in
mode RUN mode is set.
7168H A command that cannot be executed in RUN mode is
specified.
7E40H Command error A non-existing command or sub-command is specified.
7E41H Data length The number of points that can be exchanged at the time
error of random reading/writing are exceeded and specified.
7E42H Data count error The number of points requested are exceeding the range
for the command.
7E43H Device error
7F21H Receiving
header part
error
7F22H Command error There is an error in the remote password length.
7F23H MC protocol There is no data (ETX, CR-LF etc.) at the end of
message error character part or there is an error in the specification.
• Non-existing device is specified.
• A device that cannot be specified in the pertinent
command is specified.
• There is a specification error in the command (frame)
part.
• An ASCII code that cannot be converted to binary code
is received.
Troubleshooting
Refer to following manual and take measures.
MELSEC iQ-F FX5U User's Manual (Hardware)
MELSEC iQ-F FX5UC User's Manual (Hardware)
Check the sent message of the counterpart equipment, modify
it if necessary, and then execute communication again.
Check the sent message/request contents of the counterpart
equipment, modify it if necessary, and then execute
communication again.
Change the settings to make writing in RUN mode possible,
and then execute communication again.
STOP the CPU and then execute communication again.
Check the sent message of the counterpart equipment, modify
it if necessary, and then execute communication again.
Check the sent message of the counterpart equipment, modify
it if necessary, and then execute communication again.
Check the sent message of the counterpart equipment, modify
it if necessary, and then execute communication again.
Check the sent message of the counterpart equipment, modify
it if necessary, and then execute communication again.
Check the sent message of the counterpart equipment, modify
it if necessary, and then execute communication again.
Check the sent message of the counterpart equipment, modify
it if necessary, and then execute communication again.
Check the sent message of the counterpart equipment, modify
it if necessary, and then execute communication again.
4 MC PROTOCOL
4.8 Troubleshooting
4
85