Error codes
Section 5-2
97
Clearing Preset error
A Preset error can be cleared by resetting or by presetting the Counter that gen-
erated a Preset error, with a valid Preset Value. To reset a Counter refer to section
3-6
. To preset a Counter refer to section 3-4
5-2-5
Interrupt FIFO full error
Every interrupt you want to use, is assigned to an external interrupt task number
(0-255). This number corresponds with the external interrupt task in the CJ-series
CPU Unit that is to be executed when the assigned interrupt is activated (refer to
section 4-6
Multiple interrupts, will be queued in FIFO-order inside the Counter Unit, for as
long as the current active interrupt is not executed. The FIFO-buffer stores up to
30 interrupt requests. If the FIFO-buffer is full the Unit will report an error to the CJ-
series CPU Unit. All interrupts generated by the Unit, after the “Interrupt FIFO full”
error has occurred will be ignored and will not generate additional errors. Error
Code 2 contains the external interrupt task number of the corresponding interrupt
that was excluded from the full FIFO-queue.
Clearing Interrupt FIFO
error
If the speed with which the Counter Unit generates interrupts is higher than the
speed with which the CJ-series CPU Unit executes the interrupts, the FIFO-buffer
inside the Unit runs full and the “Interrupt FIFO full” error is generated. The error
can be cleared by issuing the IOWR-instruction with the Error Clear (“EC”) com-
mand (refer to section 4-5-3-4
for details).
The error indicates that the load of interrupts on the CJ-series CPU Unit is too
high. Clearing the error as mentioned before most probably needs additional
measures to be taken in order to prevent this error from happening in the future:
• Mask one or more interrupts of the Unit, which caused the error.
• Mask one or more interrupts of other Units in the system, which are generat-
ing interrupts as well.
• Reduce the execution time of the assigned External Interrupt Tasks.
External interrupt requests from the Counter Unit will not reach the CPU Unit if the
CPU Unit is not a CJ1-H or CJ1M CPU Unit (CJ1 CPU Units which do not support
external interrupts), or the Unit is mounted at an incorrect position.
Make sure that the Counter Unit is installed in the correct position. It must be
installed in one of the five positions adjacent to the CPU Unit if a CJ1-H CPU Unit
is used, or in one of the three positions adjacent the to CPU Unit if a CJ1M CPU
Unit is used.
Error Code 1
Error Code 2
Error
Description
0480
External Interrupt Task
No. (BCD)
Interrupt-FIFO full
The interrupt-FIFO inside the Counter Unit is full and
the interrupt assigned to
External Interrupt Task
could not be executed.
