Command WriteRead :

This is meant to be used by motor/loadcell devices to talk to the
controller. Do not use it directly.

The output will contain only the result, error checking is done in the
controller device, if an error occurs an exception will be thrown.

WriteRead Definition
Input Argument	Tango::DEV_STRING
Output Argument	Tango::DEV_STRING
DisplayLevel	OPERATOR	..
Inherited	false	..
Abstract	false	..
Polling Period	Not polled	..
Command allowed for	All states	..