13
DAQP-MULTI / DAQP-THERM
Amplifier function
Free programmable module range
Regardless which input mode is selected, the module measurement range is completely free programmable.
Simply by entering the lower and upper limit the amplifier adjusts its gain and offset factors automatically.
The amplifier output is scaled to either ±5 V or 0 to 5 V.With the 16-OUT-10 option which is available on
all DEWETRON signals conditioning systems also ±10 V or 0 to 10 V output signals are possible. This is
especially designed for test rig applications. Converting a nonlinear temperature signal from an RTD or a TC
to a linear 0 to 10 V analog output is one of the key features of this amplifier.
Filter
The module has 6 selectable low pass filters from 3 Hz to 1 kHz. The filter characteristic could be chosen
between Butterworth and Bessel. Also the filter order could be selected between 2
nd
,4
th
,6
th
and 8
th
order. The
2
nd
order filter up to 1 kHz is fully compatible to any other DAQP series filter.
Amplifier balance
The amplifier balance function allows automatic elimination of all internal amplifier offsets. It switches the
differential amplifier inputs IN+ and IN- to the internal isolated GND reference point. Then the output offset
of the module is automatically adjusted to zero for all ranges. All previously stored sensor offset values are
cleared.
Sensor balance
The DAQP-Multi can automatically balance any sensor offset up to 200 % of range. Depending on the input
range, also higher offsets can be balanced (e.g. input range is 100 mV/mA, excitation is 1 mA, offset can be
balanced up to 5000 %).
Short
Switches the differential amplifier inputs IN+ and IN- from the input terminals to the internal isolated GND
reference point. With this function the absolute sensor offset could be determined.
CAL
Applies a high precision internal reference signal with 80% of the full scale value (4.0000 V) to the module
output. This function allows compensating the actual error of the AD-Board, to get the full accuracy of the
DAQP-MULTI.
Open thermocouple detection
The open thermocouple detection of the DAQP-MULTI consists of an 100 MΩ pull-up resistor. That typically
drives a 50 nA current through the sensor which normally does not take effect on the measurement, but
is enough to generate an input overflow if the sensor breaks. Despite of that small current, there are
sensors available where this current generates a big error. Those sensors are typically non-contact infrared
thermocouples and fast response thermocouples. In that case the open thermocouple detection can simply
be deactivated in the software. Sensors with up to 50 kΩ output impedance could be measured in that way.
CJC
The DAQP-MULTI as well as the DAQP-THERM comes with an integrated cold junction compensation
sensor with an absolute accuracy of ±0.2 °C. In order to archieve this accuracy the sensor has to be
connected for at least 5 minutes to the thermocouple connector (CJC equilibrium time).
CJC
CJC
450134 • DAQP/H
SI
/PAD Modules • Technical Reference Manual • Prin
t
ing version 2.3.4 • November 18, 2020
Summary of Contents for DAQP-MULTI
Page 16: ...16 DAQP MULTI DAQP THERM Notes...
Page 18: ...C2 Notes...
