Mitsubishi Melsec-A Series User Manual page 141

8. TROUBlESHOOTlNG
/MELSEC
8.1.2
"HOLD"
LED
The errors shown in Table
8.4 are indicated by the AD71 "HOLD"
LED. E K O ~
5 0
or 51 indicate a hardware failure.
A bus error may be due to a hardware failure or to the sequence
program accessing too much of the buffer memory too frequently.
In the case of the latter, the sequence program must be changed in
order to allow sufficient time for the AD71 to access the buffer
memory between buffer
+
PC transactions.
Error
C o d .
C b c k Point Error h f i n i t i o n
50
51
Operation time-out error (hardware fault)
Operation error (owrflow, underflow, etc.)
.
Operation element (8231)
The PC has priority for accessing
the
buffer
AD71 bus error
may not be able t o access the data.
memory. I f accessing is tw frequent the AD71
~ ~~ ~~ ~
Table
8.4 AD71 Hold
Error
C o d e r
In the event of any of the above errors occurring 1) turn off the
AD71 ready (X11 and
2)
force BUSY processing to stop. The start
signal is then not accepted.
8.1.3 Buffer memory write errors
Writing data from the sequence program to prohibited buffer addres-
ses
or writing when the buffer cannot accept the data prompts the
error codes shown in Table
8.5.
I F z ' I
S h a r o d d m o r y
Address
I
Error Dofinition
I
Pointer value is not
0
though 20th point has
60
address w h i k BUSY.
been reached. Data has been written to pointer
39,339
61 "Speed change" during interpolation.
40,340
I
62
I
41,42,341,342
I
"Present value change" while BUSY.
1
I
64
I
Monitoring present value area Data written from PC t o a write prohibit
ad-
Speed araa dress.
I
Table 8.5 Buffer Memory Write Error
Coder
8-5
1 8
INAl66101.A