status.i4.v = dio_change_ftd(device_index.i4.r, property.i2.r,
				     ftd.i2.r [,length.i2.r] [,offset.i2.r])

	status.i4.v = dio_change_ftd_c(device_index.i4.v, property.i2.v,
				       ftd.i2.v [,length.i2.v] [,offset.i2.v])

	This routine changes the Frequency Time Descriptor (FTD) for a
	single device previously accessed via a call to dio_get_dev(_c)
	or dio_get_raw(_c).  (Note: If the same data has been requested
	with different FTDs, the most recently requested one will be

	device_index	device index
	property	property index (constants are in 'dbprops')
	ftd		Frequency Time Descriptor
			(FTD_ONESHOT -> one shot,
			 FTD_DEFAULT -> use database default FTD,
			 FTD_1HZ -> 1 Hz request (Note: This value can be
				    multiplied by an integer constant to
				    retrieve data every "constant" seconds.),
			 FTD_EVENT_MASK OR'ed with TCLK event value -> read
			 on TCLK event (event constants are in 'tclk_events')
			 (can use the macro BUILD_EVENT_FTD(event) or
			  BUILD_EVENT_PLUS_DELAY_FTD(event,delay) in 'macro'))
	[length]	data length in bytes
			(default is database minimum size (0))
	[offset]	data offset in bytes (default is 0 (0))

	This function returns ACNET status values as follows:

	OK			success
	DIO_NO_SUCH		entry not found
	DIO_UNAVAIL		not valid in this context (MIO in use)
	negative value		other ACNET format error

	This function requires the following include files:

	dbprops_h, diolib_h, acnet_errors_h, tclk_events_h, macro_h

	Related functions:

	dio_get_dev(_c), dio_get_raw(_c), dio_change_ftd_lst

	C/C++ usage:

	short	property = PRSET;
	short	ftd = FTD_1HZ;
	short	length = 0;
	short	offset = 0;
	int	status;
	int	device_index = 14430;

	status = dio_change_ftd_c(device_index,property,ftd,