Mitsubishi MELSEC LJ71C24, User Manual

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15 TROUBLESHOOTING
15.3.6 The CPRTCL instruction execution is not completed although the "RD" LED blinked
Symptom Cause Corrective action
MC
B
idi
rec
tio
na
l
Non-
proc
edur
al
P
redef
ined
• Incorrect protocol No. is
specified in the control
data.
• Check the protocol No. specified in the control data for the
CPRTCL instruction for an error.
• The CD terminal is OFF
when "CD terminal check
enabled" is set.
• If the CD terminal is OFF with "CD terminal check
enabled" set, messages will not be read. Change the
wiring so that the terminal status is always ON.
• The user-edited protocol
setting in the predefined
protocol support function
of GX Works2 is
inconsistent with the
packet format of the
external device.
• Check the packet format of the external device, and
correct the protocol setting.
(1) Check for an error in the element type or element order
in the packet setting.
(2) Check for an error in each element setting item (Code
type, Data length, Data flow, Calculating range, etc.)
• The C24 has not received
the expected packet.
• Using the circuit trace of the predefined protocol support
function of GX Works2, check for the data being
transmitted from the external device.
• When proper data are being transmitted from the external
device, take action according to Section 15.3.12 or
15.3.13.
• The C24 has cleared the
data received before the
protocol execution. (In the
"Protocol Detailed
Setting" screen of GX
Works2 predefined
protocol support function,
"Clear OS area (receive
data area) before protocol
execution" is enabled.)
• If data could be received before protocol execution,
disable the "Clear OS area (receive data area) before
protocol execution" setting in the "Protocol Detailed
Setting" screen of GX Works2 predefined protocol support
function.
• When the CPRTCL
instruction was
executed for the
protocol with
Communication type
set to "Receive Only"
or "Send and
Receive", "RD"
blinked, but the
instruction execution
was not completed.
• The C24 data
communications
monitoring time is set to
"Infinite Wait", or the
monitoring time is too
long.
• Set monitoring time or shorten the specified time, and
then transmit data from the external device to find a cause
from the timeout error.
• Part of the messages is not read.
• Transmission from the external device is interrupted.
• Perform cancel processing to complete the CPRTCL
instruction execution.