Troubleshooting - YASKAWA MP920 User Manual

7 218IF Module
7.9

Troubleshooting

This section explains how to deal with problems that may occur with 218IF communications.
Problems and Action to be Taken
Problem
1 Bind ( ) is not specified for the
TCP protocol. The connection
cannot be established from the
personal computer.
2 You wish to communicate in
ASCII mode, but the data has
not been sent to the Machine
Controller.
3
The Endian of the received
data is reversed.
4 You wish to perform com-
mand/response communica-
tions using the through mode.
5 Two connections have been
established between the per-
sonal computer and the
Machine Controller. One side
is exclusively for transmis-
sion, and the other side is
exclusively for reception, and
you wish to access these con-
nections using multiple ladder
logic programs.
Set zeroes for the DST. IP Address and the DST. Port in the
CP-218 Connection Parameter Window. Ensure that bind ( )
is performed by the application on the personal computer.
The ASCII codes that can be handled by the 218IF Module
are in the data range of 30H to 39H and 41H to 46H. There-
fore, even if spaces (20H), CR (0DH), and other unsupported
codes are transmitted, they cannot be converted, and the data
is discarded. The only way to counter this is to use binary for
the settings on the Machine Controller, and to perform code
conversion with the ladder logic program once the data has
been received.
The 218IF Module supports Little Endian. Therefore, if the
remote station supports Big Endian, Endian conversion must
be performed by one or the other. If conversion is performed
by the Machine Controller, Endian conversion for the trans-
mission and reception data must be performed by ladder
logic programming.
Create such a ladder logic program that runs while switching
MSG-SND and MSG-RCV for each connection. For exam-
ple, if the Machine Controller is a Slave, the ladder logic
program will use MSG-SND "complete" as a trigger and
execute the next MSG-RCV. During execution, the program
will not leave MSG-RCV turned ON all the time.
When an error or timeout occurs, restart from MSG-SND.
With TCP, if MSG-SND is executed at the same time from
multiple ladder logic programs for one connection, all the
data may be transmitted together in one packet.
Control the ladder logic programs in such a way that a given
ladder logic program executes MSG-SND for one connec-
tion only, and that no more than one MSG-SND is executed
at the same time.
7-44
Action