Stop MM440 on communication break with s7-200 over USS

i am controlling MM440 drive with S7-200 over USS protocol.
Every thing is alright.
But i noticed that when i disconnect the communication cable,the drive keeps on running at the last frequency set.
How to stop drive on communication break?

Not familiar with USS, but with DeviceNet, parameter p2040 must be greater than 0. If it is 0, then loss of comm is not monitored and no fault is generated that would stop the drive.