Rockwell Automation 1756-LSC8XIB8I ControlLogix Low-speed Counter Module - Manual (Page 20)

20 Rockwell Automation Publication 1756-UM536A-EN-P - April 2012
Chapter 2 Module Operation
Note that the module continues to calculate frequency and pulse width values
even if you disable counting via the Count Enable function.
Reset Count Function
The Reset Count function resets the count to zero.
To invoke the Reset Count function for a counter by using the hardware input
method, tie the function to a hardware input on the Input Configuration tab of
the Module Properties dialog box as shown in
Figure 8 .
Figure 8 - Reset Count Function Controlled by Hardware Input
When tied to a hardware input, this function is edge-sensitive resulting in a reset
when the designated input transitions low or high:
• By default, counting resets to zero on a rising pulse edge.
• When the function is inverted, counting resets to zero on a falling pulse
edge.
IMPORTANT Either the Count Enable hardware input or the corresponding bit in the
Counter[x]DisableCount output tag can determine whether counting is
enabled or disabled.
Counting is enabled under the following conditions:
• Counter[x].CountEnTieToPt configuration tag = -1 (no tie) or 0…7 and the
corresponding hardware input is non-inverted and high or inverted and
low (level-sensitive)
and
• Counter[x]DisableCount output tag = 0 (level-sensitive)
Counting is disabled under these conditions:
• Counter[x].CountEnTieToPt configuration tag = 0…7 and the
corresponding hardware input is non-inverted and low or inverted and
high (level-sensitive)
or
• Counter[x]DisableCount output tag = 1 (level-sensitive)
Reset Count function for counter 3
is tied to hardware input 5.