Omron CJ1W-CT021 Operation Manual page 69

Counter Types
Controlling Simple
Counters via CIO
32 Bits Counting Range
Reporting Overflow and
Underflow and indicating
Simple Counter
•
The Digital Inputs cannot be assigned to individual Counters and the Function
of the Digital Inputs cannot be configured. Only the status of the Digital Inputs
is reported in CIO. For information on assigning Functions to Digital Inputs for
Circular and Linear Counters refer to 3-4 "Digital Input Functions".
•
Three IORD/IOWR-commands are supported: read Captured Counter Value
(refer to 4-5-3-1 "Captured Counter Value"), read/write Counter Value (refer to
4-5-3-3 "Counter Value") and write Error Clear Command (refer to 4-5-3-5
"Error Clear Command").
•
Errors are normally reported in CIO (refer to 5-2 "Error codes").
The following features and functions are not supported for Simple Counters:
•
IORD and IOWR-instructions to change DM-settings cannot be addressed to
Simple Counters and will generate an error (refer to 5-2-2 "IOWR/IORD-
instruction errors"). Only the three above mentioned IORD/IOWR-instructions
are supported for Simple Counters.
•
Rate Measurement.
Note 1. The CPU exchanges data with the Simple Counter via the I/O Refresh Data
Area (CIO).
2. If a Counter is configured for Simple Counter, it is indicated in CIO.
3. All the DM-words that are allocated to a Simple Counter to make the Counter
Specific Settings, can be used as work-words.
Simple Counters can be controlled from CIO. For an overview of all control bits
and words refer to 4-2-3 "CIO-Memory Mapping".
The following gives a detailed description of all the features and functions for Sim-
ple Counters that are available in CIO:
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).
Lower Count Limit
-2,147,483,648
(=80000000
Underflow
If the Counter Value goes above the Upper Count Limit or below the Lower Count
Limit an Overflow or Underflow will be generated respectively. These are reported
in CIO for every Counter in the corresponding bits. At Over- and Underflow the
Counter Value will be frozen at the Upper- and Lower Count Limit respectively and
0
)
H
Up Counting
Counter Value
Section 3-2
Upper Count Limit
+2,147,483,647
(=7FFFFFFF
Down Counting
Overflow
)
H
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