Bad Reload Block Errors when trying to reload an AC256 series controller.


When I try to reload a backup into an AC256 controller I get several Bad Reload Block errors with a hexadecimal code.

Product Line



  • AC256
  • AC8
  • AC256Plus
  • AC8Plus


  • Poor serial connection.
  • Corrupt backup file
  • Insufficient line delay parameter.


Bad reload blocks errors when reloading an AC256 dump file can occur for several reasons. 

Poor serial connection:

  • Try reloading from a laptop PC directly at the CIU to eliminate the serial cable run from the equation.

Corrupt backup file:

  • When a Bad Reload Block error occurs the first portion of the failed line is displayed. 
  • View the backup file in Notepad. 
  • Do a search for the code that was displayed with the error.

In the terminal emulation application (Hyperterminal, ProComm etc)  Increase the line delay parameter for sending text two or three milliseconds.