can be characterize by the equation used by the
DMMReadCJTemp();
t
cj
= b + (V
cjs
– a) / m, the
parameters can be set using
DMMSetSensorParams()
. V
cjs
is the sensor generated voltage, a, b and m
are the coefficients which are entered using
DMMSetSensorParams()
and t
cj
the cold junction
temperature. Once set, use
DMMReqadCJTemp()
to measure the sensor temperature.
4.19 Auxiliary VDC inputs (2064)
In addition to the main voltage input terminals (V+ and V-), the SMU2064 provides two auxiliary voltage
measurement inputs, see Figure 4.25. While the DMM is in 2-Wire Ohms, DCI source or DCV source
functions, invoking one of the standard measurement functions (
DMMRead, DMMReadStr
or
DMMReadNorm
) results in voltage measurement of the top two terminals (V+ and V-). In cases where
additional voltage measurement points are required while in these operations, the I+ and I- terminals can
also be measured by using the
DMMReadHiSense
function, which returns the voltage present at the I+
terminal relative to the V- terminal. The
DMMReadLoSense
function returns the voltage present at the I-
terminal referenced to the V- terminal when the DMM is set for 2-Wire or 4-Wire Ohms. The
DMMReadHiLoSense
function reads the differential voltage between the I+ and I- terminals. The range
of measurements is limited to of ±2.4V. The accuracy is the same as is specified for the 2.4VDC range.
For higher voltages, it is necessary to provide an external divider network (Figure 4.26). When not in the
above functions, make sure these terminals are disconnected from the application.
Figure 4.24. Testing Amplifier gain and offset using the Auxiliary inputs.
Signametrics
60
