Emerson PACSystems RSTi-EP User Manual page 194

User Manual
GFK-2958J
•
•
Figure 102: Additional Counter Functions
Reset
The load value will be load into the counting value once there is a signal at the reset input.
To use this feature, you must release the reset mode in the control word (bit QX8.0) in
addition to the parameterization.
The status bit IX8.3 indicates that there is a signal at the reset input. Once a reset is done,
the status bit IX8.0 is set. This bit will be reset by deactivating the reset mode (control bit
QX9.0).
Latch Function
If a 0-1 edge appears at the latch input during a counting process, the current counter value
is stored in the latch register. The latch register is accessed through the process data inputs.
With every activation of the counter the latch value is set to 0.
Comparison Function
Via the parameter Condition for DO you can deactivate the output (never switching) or
define a comparison condition for the switching of the output:
•
•
•
Detailed Description of I/O Modules
Comparator: Upon meeting the comparison condition, the digital output is
activated, or a process alarm is triggered.
Hysteresis: reduces frequent switching of the output and/ or excessive triggering of
process alarms, e.g. when the value of a sensor signal fluctuates around the
comparison value. Figure 102 illustrates how counting behavior is affected by the
additional features. These additional features are explained in the following pages.
Counter value higher or equal comparison value
Counter value lower or equal comparison value
Counter value equal comparison value
Chapter 5
Oct 2019
179