Mitsubishi MELSEC-A series User Manual

8. TROUBlESHOOTlNG /MELSEC-A
8.1.2 "HOLD" LED
The errors shown in Table 8.4 are indicated by the AD71 "HOLD"
LED. EKO~ 50 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
Cod.
Cbck Point Error hfinition
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 to access the data.
memory. If accessing is tw frequent the AD71
~ ~~ ~~ ~
Table 8.4 AD71 Hold Error Coder
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 Fz' I Sharoddmory Address I Error Dofinition
I
Pointer value is not 0 though 20th point has
60
address whik 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 to a write prohibit ad-
Speed araa dress.
I
Table 8.5 Buffer Memory Write Error Coder
8-5
18 INAl66101.A

Mitsubishi MELSEC-A series Specifications

General

Brand	Mitsubishi
Model	MELSEC-A series
Category	Controller
Language	English