Dedicated Protocol Led Display Contents - Mitsubishi Electric AJ71QC24 Manual

4. COMMUNICATIONS USING A DEDICATED PROTOCOL MELSEC QnA
4.3
Dedicated Protocol LED Display Contents
The following shows the display contents of the AJ71 QC24 LEDs related to dedicated protocol
data communications with the system configuration described in Section 3.1.1.
LED Name
ON
OFF LED
Applications
RUN
QC24 operation status dis-
play
Module normal
Module abnor-
mal
Check the number set at the mode
switches.
CPU
RAN
QC24 and PC CPU commu-
nications status
Blinks while com
m u n i c a t i n <
(Lights steadil!
while communi
cations stopped
Abnormal Check the status of the PC CPU and ex-
Check the number set at the mode
ternal device.
switches.
I
1
-NEU Displays the QC24 process-
ing status for a request from
the external device.
Waiting for re
quest from exter
nal device
Processing a re-
quest from ex-
ternal device
If
the display does not change even when
the external device sends a command, check
the following.
Cable connections
Number set at mode switches 1
-ACK Preceding re.
quest ended nor
mally
Preceding re.
quest ended ab.
normally
Preceding re-
quest ended ab-
normally
Preceding re-
quest ended
normally
1
-NAK
1
-C/N QC24 and PC CPU commu-
nications status display
Communication5
abnormal
Communica-
tions normal
n
Check
SW07
(Enable/disable write during
RUN)
1
-P/S Parity and checksum error
display
Error Normal
3eceive data and transmission specifications
settings are not the same.
B
Make the QC24 transmission specifica-
tions and the external device transmission
specifications the same.
B
Check the transmission specifications
switches.
1
-PRO
Protocol status display Error Normal Uode setting and receive data format are not
:he same.
B
Check the number set at the mode
1
Check the external device send message.
rransmission specifications settings and re-
:eive data are not the same.
Make the QC24 transmission specifica-
tions and the external device transmission
specifications the same.
1
Check the transmission specifications
switches.
1
Decrease the transmission rate.
switches.
1 -SI0
3ata reception status display Error Normal
1
-SD
.
WAIT Waiting
to
send Sending
No
send data
Shows the status of the data
sent
to
the external device
' T om the QC24
1 -SD Not sending
data
X 2 4
to
external device send
status
X 2 4 from external device
~eceiving status
Blinks while data
is being sent
Blinks while data
IS
being received
1
If
this LED does not blink even when the
external device is sending a command,
check the cable connections.
1
-RD
Data not being
?eceived
CHI. ERR
2H1
communications status
jisplay
CHI error
1
Uormal
even if the error recovers. Use the buffer memory (201 H) to turn OFF the error LED.
4 - 1 2