PNI RM3000 Evaluation Board - Manual (Page 6)

PNI Sensor Corporation Doc #1015790 r03
RM3000 Evaluation Board User Manual – June 2011 Page 6 of 19
typical relationship between cycle counts, gain, and resolution. Above ~200 cycle counts noise is
relatively constant and there are diminishing returns in resolution as the cycle count value
increases. Also, performance will vary from sensor to sensor: ~50% of the sensors will have
performance greater than “Typical” and ~50% less than “Typical”.
4) The maximum sample rate and gain/resolution are inversely related, so higher sample rates
can be obtained by reducing the number of cycle counts, but this also results in reduced gain
and resolution.
Also see Figure 3-1 and Figure 3-2.
5) Operating at reduced cycle counts will reduce current consumption, but also reduce resolution.
Operating at greater cycle counts will increase power consumption but generally not provide any
benefit. 35 Hz single-axis output rate represents ~12 Hz output rate for all 3 axes for the RM3000
Evaluation Board. Also see Figure 3-3.
3.2 Typical Operating Performance
Figure 3-1, Figure 3-2, and Figure 3-3 show performance when operating out to 200 cycle
counts. Operation at more than 200 cycle counts usually is inefficient since more time and
power is consumed per measurement, with little improvement in usable (noise-limited)
resolution.
Figure 3-1: Gain vs. Cycle Counts
0
5
10
15
20
25
30
35
40
45
50
0 20 40 60 80 100 120 140 160 180 200
G
a
in
(c
o
u
n
ts
/µ
T
)
Cycle Counts