error 401

[Al Geiser]

Hi I have a D0-05DR-D PLC with a 38 rung programe to control the running spped of a small hydro electric plant.  I wrote the program and ran it for several days in the shop.  Then it came up with the 401 error code and it won't go away.  The end output is there.  I tried erasing it and reentering no luck I entered several END and no luck.
As soon as the communication link is established it comes up with the "error 401" which of course lets nothing else work.

I have tried a second PLC with the same results.
I would like to completly zero the PLC but can't see the command for that and am afraid that won't be the answer as the second PLC picked up the same problem.
I ran an anti virus on the program to no effect.

Any input will be appreciated. Al Geiser

[b_carlton]

Can you zip and post your program? I'll look at it immediately.

[b_carlton]

Error 401 is what I would expect to see on a new CPU which has no program in it. Are you sure the program is still in the CPU? I ignore the error on a new CPU and download my program to it. On placing it in 'run' the error goes away.