Operator`s manual

Signametrics 74
Negative Value
Error code
Example int status = DMMCloseUSB(0);
DMMDelayedTrigger
SMU2060  SMU2064 
Description Arm DMM for delayed external trigger operation.
#include "SMU2060.h"
#include "SMU2060.h"
int DMMDelayedTrigger(int nDmm, double dDelay, int iSamples)
Remarks Setup for delayed external trigger capture mode (off the DIN7 connector). Following
reception of this command the DMM enters a wait state, waiting for trigger edge
currently selected (see DMMSetTrigPolarity()). At the detection of the selected polarity,
the DMM waits for dDelay prior to making iSamples samples. The value of dDelay can
be set between 0 and 1s. The samples are taken using the currently set function, range,
Aperture (DMMSetAperture) and Read-Interval (DMMSetReadInterval). iSamples are
stored in the DMM’s internal buffer. With the exception of the DMMReady and
DMMDisarmTrigger commands, following the issue of DMMDelayedTrigger command,
no other function should be used prior to reading the captured data. This function is
usable in VDC, VAC, Ohms, IAC, RTD and IDC.
Read Interval must be set between 0 (default) and 65ms. Aperture must be set between
160ms and 2.5us. The value of iPostSamples must be set between 1 and the buffer size.
The buffer size is 80 for Apertures of 160ms to 1.4ms, and 120 for Apertures in the range
of 2.5µs to 625us. The highest Aperture allowed for this operation is 160ms. Aperture
and Read Interval are set using the DMMSetAperture and DMMSetReadInteval
functions, respectively.
Following DMMDelayedTrigger, use the DMMReady to monitor completion of the
capture process. When the DMM is ready read the buffer using DMMReadBuffer or
DMMReadBufferStr functions. Read iSamples measurements from the buffer. Once
DMMReady returns TRUE, it should not be called again since it prepares the buffer for
reading when it detects a ready condition. Other related functions include; DMMReady,
DMMReadBuffer, DMMReadBufferStr, DMMSetReadInterval, DMMSetSync,
DMMSetTrigPolarity, DMMDisarmTrigger.
Parameter
Type/Description
nDmm
int Identifies the DMM. DMMs are numbered starting with zero.
dDelay
double This post-trigger delay value can be 0.0 to 1.0
iSamples
int The number of samples the DMM takes following a trigger. This
value must be between 1 and 80 or 120 depending on set resolution.
Example double Buffer[50]; //Delay 0.1s, take 50 samples
DMMDelayedTrigger(0, 0.1, 50);
while( ! DMMReady(0) ); // wait for completion
for(i=0;i<50;i++) DMMReadBuffer(nDmm, Buffer[i]); // read