Operator`s manual

Signametrics 140
Description Set the cold junction temperature sensor equation parameters.
#include "SMU2060.h"
int DMMSetSensorParams(int nDmm, double lda, double ldm, double ldb)
Remarks This function sets the parameters of the temperature sensor. It effects the cold junction
termerature reading which is defined by ((Vcjs - lda) / ldm) + ldb, where Vcjs is the cold
junction sensor output voltage. This function set the paramters for the sensor as to allow
a wide range of sensors to be used. The default parameters are designed to work with the
Signametrics Temperature sensor found on the SM40T and SMX40T screw terminals.
The cold junction temperature is calculated by converting the sensor’s voltage to
temperature. For more information read about DMMReadCJTemp().
Parameter
Type/Description
nDmm
int Identifies the DMM. DMMs are numbered starting with zero.
lda
double the ‘a’ parameter.
ldm
double the ‘m’ parameter.
ldb
double the ‘b’ parameter.
Return Value Integer error code.
Value
Meaning
DMM_OKAY
Operation successfully completed.
Negative Value
Error code
Example
DMMSetSensorParams(0, 0.558, -0.002, 22.0);// set parameters
DMMSetSourceMode
SMU2060  SMU2064 
Description Set the DCV and ACV sources to ClosedLoop, or OpenLoop mode.
#include "SMU2060.h"
#include "USBDMMUser.h"
int DMMSetSourceMode(int nDmm, int iMode)
Remarks This function sets the DC voltage sources to either OPEN_LOOP (‘O’, default) or
CLOSED_LOOP (‘C’). In CLOSED_LOOP the sources use the main 12 bit source
DAC. In CLOSED_LOOP the Trim DAC is also used, which augments the 12 bit DAC
to produce 18 effective bits. Open loop updates are very quick. In ClosedLoop mode the
source level is adjusted every time the DMM is read, making small corrections until the
reading is equal to the set voltage. However, for the ClosedLoop mode to update the
source level, it is necessary to read the DMM multiple times. See DMMSetDCVSource
for more details. Another function effected by this function is the DC Currents souce.
When in OPEN_LOOP, the voltage generated by the DC current source is measured at
the source terminals (upper two), when in CLOSED_LOOP the voltage is measured at
the sense terminals (lower two) of the DMM. This allows a 2-Wire or 4-Wire
measurement of the current source.