Why I get the error message "NAK response" during a program download (with PG5 SP2)?

FAQ #101656

On download of a big program with PG5 2.0.200 to a PCD1.M2xx0 or PCD3.Mxx60 the error message "Command not accepted: NAK response" can be returned by the downloader.


When downloading a big program with PG5 2.0.200 to a PCD1.M2xx0 or PCD3.Mxx60 and in the option "Halt the PCD" before download is activated, the error message "Command not accepted: NAK response" can appear and the download is aborted.

The problem in this case is that the commanded restart of the PCD does take longer than PG5 expects. The restart is commanded in order to bring the PCD into a defined state during the download.

Please update your PG5 to version 2.0.210 or later.


  • In case it is not possible to use version 2.0.210, the following workaround could be applied:
    Activate "Stay in run" before download in the Download Program to solve this problem.
    It isn't possible to select the option "Delete Backups from all Flash Cards" if the PCD is not halted (and the download is not possible if the PCD is halted before download due to the above described problem.
    In order to work around this trouble, just select "Backup to Onboard Flash" and "Backup to Flash Card" (if you have plugged a module e.g. in M1 slot). This way the backups will be deleted automatically before the new backup is created.


PCD3 / Mxxx

PG5 2.0

PCD1 / M2xx0

Last update: 29.05.2015 21:14

First release: 11.08.2011 12:41

Views: 17424

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