Excel 800
EN1B-0410GE51 R0908A
34
I/O Modules Troubleshooting
► Check if the power supply voltage level is OK and that there is no high voltage (> 24 VAC or > 40 VDC) connected to the
inputs/outputs of the XF821AU, XFL821AU, XF822AU, XFL822AU, XFR822AU, XFLR822AU, XF823AU, and XFL823AU I/O
modules.
► Replace the problem I/O module with another module of the same kind.
– If the problem persists, this is an indication that the problem is caused by the application or incorrect wiring.
– If the problem is solved, this is an indication that the I/O module was defective.
For troubleshooting purposes on all I/O modules the following features can be used:
• Power LED
• Service LED
• Service button
In addition, a module-specific troubleshooting may be necessary.
Power LED of I/O Modules
Table 42. Power LED of I/O modules
case power LED meaning remedy
1 ON
I/O module is powered
No action necessary
2 OFF
No power
► Check power supply
3 Flashing continuously
If the I/O module’s service LED is likewise
flashing, the I/O module is in the boot mode
► Wait until rebooting (firmware
download) has been completed
