Jäger ADwin-Pro, System And Hardware Description

Page: 127 / 218

ADwin-Pro Hardware, manual version 2.9, June 2006
123
Pro I: Digital-I/O- and Counter Modules
Pro-CNT-PW4-I Rev. A
ADwin
5.8.16 Pro-CNT-PW4-I Rev. A
To this module you find an improved successor module Pro-CO4-I Rev. A (see
page 127 ).
The digital counter module Pro-CNT-PW4-I Rev. A has four inputs for pulse
width modulated signal acquisition. The inputs are optically isolated from each
other as well as from the system circuit. The switching time of only 200ns per-
mits the reading of fast digital signals. The event input is isolated from the sys-
tem, too. The input voltage range of the counter inputs can be selected by
jumpers. The default setting of the input voltage range is 24V.
With this module you are able to determine the positive and negative pulse
widths of up to four signals and to calculate the duty cycle, period time and fre-
quency The 4 counters (32 bit) are clocked with a fixed 5MHz clock signal. At
the rising and falling edges of the PW-input signal, the counter value will be
stored in two separate latches.
Please, make sure that the delay of the event (via internal or external timer) is
smaller than the period width of the highest input frequency. to be measured.
Example: The signal whose positive and negative pulse widths you want to
know has a frequency of 3.3kHz Þ The event has to arrive in a time interval of
less than 303µs (= 1/3.3kHz).
Fig. 234 – Pro-CNT-PW4-I Rev. A : Block diagram
Fig. 235 – Pro-CNT-PW4-I Rev. A : Pin assignment
The module Pro-CNT-PW4-I is equipped with 4 times the components shown
in the block diagram; exception: the event input and the control register which
can only be found once on the modules.
NOTE: Only Counter #1 is shown for clarity of the schematic.
Control registers
32 bit Counter #1...#4
32 bit Latch #5...#8
CLK
EN
CLR
ADwi
n
-P
ro
bus
32 bit Latch #1...#4
G
5 MHz
+
-
PW #n
24V
12V
5V
+
-
EVENT
24V
12V
5V
4k3
2k
560
4k3
2k
560
PW INPUT 1 (-)
PW INPUT 2 (-)
PW INPUT 3 (-)
PW INPUT 4 (-)
DGND
EVENT IN (+)
PW INPUT 1 (+)
PW INPUT 2 (+)
PW INPUT 3 (+)
PW INPUT 4 (+)
DGND
RESERVED
EVENT IN (-)
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
37
36
35
34
33
32
31
30
29
28
27
26
25
24
23
22
21
20
RESERVED
RESERVED
RESERVED
RESERVED
RESERVED
RESERVED
RESERVED
RESERVED