Measurement Computing CIO-EXP-GP - Manual (Page 14)

4.4.2 Setting Channel Gain
CH0
X1000 X100 X10 U
GAIN FOR CHANNELS 0 and 4
SET FOR A GAIN OF 10.
SLIDER DOWN SELECTS GAIN
ALL OTHERS TO BE OFF (UP)
O
N
O
N
CH4
Select a gain (higher than unity) by moving the switch for
that gain down. All other switches should be left in the
UP position..
A custom gain may be selected on the CIO-EXP-GP by
installing a precision resistor and setting the switch
marked “U” (User) in the down position. See Table 4-1
following for board positions and some sample gain
values.
Figure 4-2. Input Channel Gain Select Switches
Table 4-1. Resistor Positions for User-Selected Gains
RX107 7 RX103 3
RX106 6 RX102 2
RX105 5 RX101 1
RX104 4 RX100 0
Resistor Position Channel Resistor Position Channel
10 Ohms 800
17 Ohms 700
40 Ohms 500
161 Ohms 200
364 Ohms 100
776 Ohms 50
Resistor Value Gain
The equation for selecting the USER gain resistor is:
R
USER
= [40000 / (Gain
−
1)]
−
40
Amplifying a signal on one channel will not affect the reading on another channel.
4.5 Attenuation
If your signal is in a range greater than the full scale range of the A/D, you must either set the A/D for a
higher full scale range (if available) or divide (attenuate) the signal until the result is less than or equal to
the A/D’s full scale range. This section describes signal attenuation.
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