Chapter 3 Signal Conditioning Application Examples
National Instruments Corporation
3-3
BNC-2090 User Manual
Soldering and Desoldering on the BNC-2090
Some applications require you to modify the PWB, usually by removing
0
Ω
jumpers and adding components. The BNC-2090 is shipped with
0
Ω
jumpers in the C and D positions (see Table 3-1 and Figure 3-2).
Use vacuum-type tools when desoldering on the BNC-2090 and avoid
damaging component pads.
Use a low-wattage soldering iron (20 to 30 W) when soldering to the
board. You should use only rosin-core, electronic-grade solder. Acid-
core solder damages the printed circuit board and components.
Analog Input
Each analog input signal has several open positions for passive signal
conditioning components. Four of these positions are designated as
resistors and one is designated as a capacitor. The factory-default
positions for the 0
Ω
jumpers are the C and D positions of the input
network, as shown in Figure 3-2. You can remove these 0
Ω
jumpers to
build analog input signal conditioning circuits. You can also add
passive analog input signal conditioning, such as filters and dividers.
The component positions are different for each channel. Figure 3-2
shows the onboard equivalent circuit.
Table 3-1.
Channel Component Positions
Channel
Position in Figure 3-2
Differential
Single-Ended
A
B
C
D
E
0
0, 8
R1
R2
R19
R20
C1
1
1, 9
R3
R4
R21
R22
C2
2
2, 10
R5
R6
R23
R24
C3
3
3, 11
R7
R8
R25
R26
C4
4
4, 12
R9
R10
R27
R28
C5
5
5, 13
R11
R12
R29
R30
C6