Analogue Inputs / Ranges; Ranges - Intab PC-Logger 2100 User Manual

2

ANALOGUE INPUTS / RANGES

All analogue channels are DIFFERENTIAL. They measure the voltage between -
and GND and the voltage between + and GND. The subtraction is then
performed internally.
Standard inputs are balanced. This makes them very insensitive to noise if the
signal source is correctly connected. A signal cable consisting of a twisted pair
can be very long if the lowest potential of the source is connected to ground via a
separate cable.
Each channel is individually programmable. It can via the software be set to
measure voltage, current or temperature (thermo emf). The range (=sensitivity)
for each unit (voltage, current, temperature) is also programmable.
This versatile property can be compared to the rotary switch on an ordinary
multimeter with the difference that the user has to press a few keys on the
computer instead (see software manual).
Several types of T/C´s can be employed in the same recording and still be
correctly linearized.
2.1

Ranges

There are approx. 25000 divisions of each range. To put it in other words: each
range has a resolution of FS/25000.
Here is a table of main ranges and their resolutions:
Each channel has an internal shunt (51ohms) that is used to measure current. It
must be connected manually via an external jumper in the screw terminal (see
Section 3.4.2.)
NOTE that the shunt will overheat if subjected to more than 80mA.
Page 6
RANGE
+/- 10V
+/- 1V
+/- 100mV
+/- 50mV
+/- 20mA
INTAB Interface-Teknik AB, Sweden
RESOLUTION
400 µV
40 µV
4 µV
2 µV
0.8µA