Operator`s manual

Signametrics 146
DMMSetTrimDAC
SMU2060  SMU2064 
Description Set the Trim DAC level.
#include "SMU2060.h"
#include "USBDMMUser.h"
int DMMSetTrimDAC(int nDmm, int iValue)
Remarks This function sets the Trim DAC to a value between 0 and 100. The trim DAC can be set
to augment the main 12 bit DAC, whenever it is not automatically performed, such as in
VDC and VAC source while OPEN_LOOP mode is selected. An example would be in
DCI source, or when setting the Comparator Threshold. This function consumes a lot of
the on-board microcontroller’s resources and must
be turned off when not in use. Use
DMMDisableTrimDAC to turn it off. With the Trim DAC the effective resolution of the
composite DAC is increased to 16 bits. See DMMSetDCVSource and
DMMSetACVSource for more details.
Parameter
Type/Description
nDmm
int Identifies the DMM. DMMs are numbered starting with zero.
iValue
int Amplitude can be set from 0 to 100, corresponding to 0% to
100% Trim DAC level.
Return Value Integer error code.
Value
Meaning
DMM_OKAY
Operation successfully completed.
Negative Value
Error code
Example
DMMSetDCVSource(0, 5.0); // Set source to 5V
DMMSetTrimDAC(0, 50); // add about 2.5mV to output
DMMStartTotalizer
SMU2060  SMU2064 
Description Clear the totalized value and start the totalizer.
#include "USBDMMUser.h"
#include "SMU2060.h"
int DMMStartTotalizer(int nDmm, int Edge)
Remarks To use this function the DMM must be in ACV measurement function, and a valid range
must be selected. This function clears the Totalized count, sets the edge sense, and starts
the Totalizer. The totalized value can be read during the accumulation period. However,
it could affect the count by the interruption. If no reads are performed during
accumulation, the input rate can be as high as 30,000 events per second. If reads are
performed during the accumulation period, this rate could be as low as 20,000 events per
second. The Threshold DAC sets the threshold at which signals are counted. During
accumulation, no other command (except DMMReadTotalizer) should be used. When
done, this function must be turned off using DMMStopTotalizer. After the Totalizer is
stopped, the accumulated result can be read using DMMReadTotalizer. A normal
procedure would be to set the DMM to the ACV function, select voltage range, set the