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Rollover
Each of the two counters has one rollover value that is associated with it. When
the accumulated count value in the Rollover tag reaches the rollover value, it
resets to zero (0) and begins counting again. The rollover value is circular.
For example, if the rollover value = 360, the count will be from 358, 359, 0, 1, and
so forth, in a positive direction and from 1, 0, 359, 358, and so forth, in a
negative direction.
Rollover values are entered on the Counter Configuration tab of the Module
Properties dialog box in the programming software or can be changed in
ladder logic.
See
page 60
for an example of the Counter Configuration tab.
Rollover in Output tag
When using the HSC Data-extended Comm Format while configuring the
module, the Rollover tag is found in both the Configuration and Output tag
areas.
The Configuration tag value is populated during software configuration with
the Logix 5000 controller, and sent to the module upon power-up, defining its
behavior. This value continues to define module behavior as long as the
corresponding tag in the Output area is zero.
If the value of the Rollover tag in the Output area is changed to a nonzero
value, the module disregards the value that is sent from the Configuration area
and use the value in the Output area instead. This facilitates easier real-time
'on-the-fly' changes to the Rollover function.
Input Z (Gate/Reset)
Input Z, when active, will change the behavior of an accumulated count value
in the Present Value tag, depending upon which of four modes are selected.
•
Store and Continue Mode
•
Store, Wait, and Resume
•
Store and Reset, Wait, and Start
•
Store and Reset, and Start
The Storage modes are selected on the Counter Configuration tab on the
Module Properties dialog box of the programming software.
Rockwell Automation Publication 1756-UM007E-EN-P - August 2021
Chapter 2
Counter Modes
19
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