PCI 703 User Manual
Eagle Technology - Data Acquisition
Eagle Technology © Copyright 2001-2004 – www.eagledaq.com
25
F3
F2
F1
F0
R
3
R
2
R
1
R
0
G
7
G
6
G
5
G
4
G
3
G
2
G
1
G
0
ListSize
Unsigned long
This parameter determines the length the two previous arrays. This is also the depth of the channel list
that is programmed to the board.
The range code does not apply to the S models, for the are always differenti al and bipolar.
The
Frequency
and
ClockSource
ADC ActiveX control must be setup before calling the
configure function.
EDREADX.Frequency
Frequency
The ADC sampling frequency
WARNING!!
î
On the PCI703 the frequency is the
update rate of the A/D converter. This
means that the board will convert the
channels at a period of equal to the
frequency and the channels in the
sequence of the channel list. The end
result is that the time between samples is
equal to 1/Frequency.
î
The PCI703S -frequency relates to th e
total sampling frequency. The effective
sampling frequency is the
frequency
divided by the channel list length. The
channel-list holds all the channels that
need to be simultaneous -sampled-and-
holded. Thus the all channel in a set are
sampled at the same time but the space
between a set is the total sampling
frequency divided by the channel list
length. Also note that the sample-and-
hold counts as one channel. This reduces
the maximum frequency by one count
plus the channel list length. For example
the max for one channel is 200KHz.
Frequency Example:
PCI703
PCI703S
Frequency = 200 000 Hz
Channel List Length = 10
Time = 5 uS
Time between channels = 5 uS
Frequency = 200 000 Hz
Channel List Length = 10
Effective Frequency = 20 000 Hz
Time = 50 uS
Time between channels = 0 uS
Time between sets = 50 uS
