Proface to Festo CMMP servo with CANopen

Hi All - trying to get a Proface SP5000 integrated HMI/PLC to communicate with a Festo CMMP controller using CANopen - the control will be using the Festo FHPP interface for sending and receiving commands to the drive. EDS file loaded OK, but as soon as the devices power up, the Festo seems to reset and go back to factory defaults and Festo don't seem to know why? The Proface reports an error of 'Inconsistent cDCF' but can see the controller. If I change the identity setting number in the Proface slave configuration from 2 to anything else the reset of the Festo doesn't happen but then the Proface reports an 'Identity error' and therefore doesn't recognise the unit.
Has anyone successfully got the two devices communicating or have any thoughts on a resolution.
Thanks in anticipation of your help.