Alarm 27251

Dear all,

I have a lathe machine with system control of sinumerik 840Dsl,

after load NCK&plc, this machine have 2 alarm:

27251 PROFIsafe:F module 1021,Master reports error TO,CRC

27251 PROFIsafe:F module 1022,Master reports error TO,CRC

How can solve this Faults,

thank’s All

Has the problem been solved?

I meet the same alarm now , 27251

Hope for your reply.