Operator`s manual

97 Signametrics
nDmm
int Identifies the DMM. DMMs are numbered starting
with zero.
Return Value Integer error code or.
Value
Meaning
0
Trigger line is at a low logic level (< 0.7V).
1
Trigger line is at a high logic level (> 3.5V).
Negative value
If an error detected.
Positive value > 100
If warning
Example status = DMMGetTrigger(0);
DMMGetTriggerInfo
SMU2060  SMU2064 
Description Get Capture Infromation following Trigger operation.
#include "SMU2060.h"
int DMMGetTriggerInfo(int nDmm int * iNullCount, int * iPreTrig, int *iBufCycles)
Remarks This function returns various parameters associated with previous trigger operation. For
instance, if the trigger event occurred soon after DMMArmTrigger command is issued,
the buffer does have a chance to fill. That is the total number of pre trigger samples plus
post trigger samples is less than the size of the buffer. The iNullCount is the number of
these “empty” samples at the beginning of the buffer. These empty samples should be
ignored when reading the buffer by reading and discarding iNullCount samples. The
iPreTrig value is the number of valid samples taken prior to the trigger event. If the
circular buffer fills at least once, or “wraps”, the value of iBufCycles will be greater than
0. Than the sum of iPreTrig and iPostTrig samples is equate to the size of the buffer.
The amount of time the trigger event occurred following the issue of the command may
be calculated using the following relation:
tTriggDelay = iReadInterval * ( (iBufCycles * 120) + iPreTrig)
Other related functions include; DMMArmTrigger, DMMGetTriggerInfo,
DMMReadBuffer, DMMReadBufferStr, DMMSetReadInterval,
DMMSetSync, DMMSetTrigPolarity, DMMDisarmTrigger.
Parameter
Type/Description
nDmm
int Identifies the DMM. DMMs are numbered starting with zero.