Rockwell Automation 1756-LSC8XIB8I ControlLogix Low-speed Counter Module - Manual (Page 21)

Rockwell Automation Publication 1756-UM536A-EN-P - April 2012 21
Module Operation Chapter 2
To invoke the Reset Count function by using the output tag method, use the
Counter[
x].ResetCount output tag as shown in
Figure 9 .
Figure 9 - Counter[x]ResetCount Output Tag
Preset Count Function
A preset value determines the starting value for a count. Each counter can have
one preset value defined in the Counter[
x].Preset output tag.
The following criteria applies to a preset value:
• The default preset value is zero.
• A preset value must be a non-negative DINT value.
• A preset value must be less than the rollover value. If the preset value is
greater than or equal to the rollover value, then the module uses the
requested rollover value and the default preset value of zero rather than the
invalid preset value.
IMPORTANT Either the Reset Count hardware input or the corresponding bit in the
Counter[x]ResetCount output tag can determine whether the count is reset.
Counting is reset to zero under the following conditions:
• Counter[x].ResetTieToPt configuration tag = 0…7 (rising edge-sensitive)
or
• Counter[x]ResetCount output tag = 1 (rising edge-sensitive)
EXAMPLE A preset value of 99 produces the following count sequences:
• Increasing count sequence: 99, 100, 101, …
• Decreasing count sequence: 99, 98, 97, …
0 = Tag-based reset is not
active.
1 = Count transitions to zero
on a rising edge.