0)&*'#"-CD4#+
Section 3-2
',
Controlling Simple
Counters via CIO
Simple Counters can be controlled from CIO. For an overview of all control bits
and words refer to 4-2-3
.
The following gives a detailed description of all the features and functions for Sim-
ple Counters that are available in CIO:
32 Bits Counting Range
A Simple Counter has the full counting range (=32 bits) available to count up- or
downwards over the positive and negative counting range between the Lower
Count Limit (–2,147,483,648) and the Upper Count Limit (+2,147,483,647).
Reporting Overflow and
Underflow and indicating
Simple Counter
If the Counter Value goes above the Upper Count Limit or below the Lower Count
Limit an Overflow- and Underflow will be generated respectively. These are
reported in CIO for every Counter in the corresponding bits. At Over- and Under-
flow the Counter Value will be frozen at the Upper- and Lower Count Limit respec-
tively and received count pulses will have no effect. The Over- and Underflow flags
can be cleared by forcing a Preset or a Reset.
Gating of a Simple Counter
The Gate of a Simple Counter can be opened and closed using the “Open Gate
Bit” and “Close Gate Bit” in CIO. If the Gate of the Simple Counter is Open the
Counter is ready to count pulses. If the Gate of the Simple Counter is Closed the
Counter will not count pulses. A rising edge of the Open- or Close Gate Bit triggers
the corresponding action in the next I/O Refresh Cycle.
Initially, after the High-speed Counter Unit has been powered up or restarted, the
Gate of the Simple Counter is closed and must be opened first (by setting the
Open Gate bit to ‘1’) to enable counting.
0
Lower Count Limit
-2,147,483,648
(=80000000
H
)
Upper Count Limit
-2,147,483,647
(=7FFFFFFF
H
)
Up Counting
Counter Value
Down Counting
Overflow
Underflow
CNT1:
CNT2:
CNT3:
CNT4:
n+24
n+29
n+34
n+39
Counter Overflow:
0 = No Overflow
1 = Overflow
Counter Underflow:
0 = No Underflow
1 = Underflow
Simple Counter Indication:
0 = Circular/Linear Counter
1 = Simple Counter
15 14 13 12 11 10
9
8
7
6
5
4
3
2
1
0
W902-E2-03.book Seite 49 Donnerstag, 7. Oktober 2004 2:06 14
Summary of Contents for CS1W-CT021
Page 1: ...OPERATION MANUAL High speed Counter Units CS1W CT021 CS1W CT041 Cat No W902 E2 03...
Page 3: ...W902 E2 03 book Seite iv Donnerstag 7 Oktober 2004 2 06 14...
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