Basic I/O Error

What does 009A mean?

This is a non-fatal error indicating a problem with a Basic I/O Unit. The POWER and RUN indicators will be lit, while the ERR/ALM indicator will be flashing. Additional error details, including the slot and rack number of the faulty unit, are available in memory area A408. This error prevents normal operation of the affected I/O unit.

• A fuse on the Basic I/O Unit or its power supply circuit is burned out.
• The external 24VDC power supply to the Basic I/O Unit is OFF or disconnected.
• Other internal errors specific to the Basic I/O Unit itself.

Click steps to track your progress.

1. 1

   Measure the voltage at the power supply terminals of the Basic I/O Unit — expect 24VDC.

2. 2

   If 24VDC is not present and a fuse is suspected, replace the fuse.

3. 3

   If 24VDC is not present, verify the external power supply is ON and connected.

4. 4

   Check the error information stored in memory area A408 to identify the specific slot and rack number of the faulty Basic I/O Unit.

5. 5

   Replace the Basic I/O Unit identified by the A408 error information.

6. 6

   Restart the system after addressing the identified cause and replacing any faulty components.