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Chapter 4: Channel Configuration, Data, and Status
35
Note: In extended count mode (counts up to +/- 8M) the preset will be
multiplied by 256 internally such that a user preset of 1000 will result
in a preset of 25600. This allows the preset value to cover the whole
+/- 8 million count range.
In program scale factor mode an M Factor is stored in the module’s non-
volatile memory. If an M Factor is defined (not zero) then the data value
output for the counter value will be COUNT x (M Factor/10,000). A
value of zero must be written to the M Factor to disable this feature.
Figure 4.7 - Limit / M Factor Word
15
0
Address
Counter Limit / M Factor
O:e.y
Example:
An M Factor of 10,200 will increase the output count by 2%.
Output Count = Input Count * 10,200/10,000
Output Count = Input Count * 1.02
Note: When the count size is extended to ±8M using Configuration Bit
11, the Counters Maximum flag is extended to ±8M. The counter
Preset and Limit values are also extended to ±8M. This means that
the resolution of the Preset and Limit values are set in blocks of 256
counts (8bits). This allows the preset and limit values to cover the
whole ±8M bit range. Refer to the applications section of this
manual for more information about setting limit and scale values.
Counter Limit / K Factor:
The counter limit mode is used in Normal operation mode. This input data
word is used in conjunction with the Scale / Limit Mode enable bit. When
the counter limit bit is set, the counter limit flag will be active. When the
counter value is greater then or equal to the Limit value the Counter Limit
flag bit will be set. If the Stop On Limit bit is set the counter will not
exceed the counter limit.
Note: When operating in standard count mode, if the K Factor x
Count Limit is > 32767 a configuration error will occur.
Note: In extended counter mode the limit will be multiplied by 256
internally such that a user limit of 1000 will result in a limit of
256,000.
In program scale factor mode a K factor is stored in the module’s non-
volatile memory. If a K Factor is defined (not zero) then the data value
output for the counter is the counter value divided by the K Factor. A
value of zero must be written to the K Factor to disable this feature.
Figure 4.6 - Preset / K Factor Word
15
0
Address
Counter Preset / K Factor
O:e.x
Summary of Contents for 1746sc-CTR4
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