Instruction Manual

74 Rockwell Automation Publication 1769-UM006E-EN-P - July 2013
Chapter 4 Module Configuration, Output, and Input Data
Figure 20 - Configuration for Individual Counter Reset Disable
As shown in Figure 20, the Counter Reset Enable box has been unchecked to
indicate the individual counter reset functionality is disabled for the selected
counter of the 1769-HSC/B module. The corresponding controller tag in
RSLogix 5000 software shows a one (1) for disabled.
The CtrReset bit, when set, causes the following to occur for both the
1769-HSC/A and 1769-HSC/B modules when the system transitions to Run or
the Inhibit Module bit transitions to 0:
• System checks counter reset selection bits 12…15 to determine which
counter needs to be reset.
(1)
• Only those counters selected for reset are reset to zero.
• The output array is reset to default values until the ModConfig bit is
set (1). The default value for the output array is all zeros.
• The input array counter status flags (Overflow, Underflow, RisingEdgeZ,
RateValid, PresetWarning) are reset.
• The input array counter values (Current Count
(2)
, StoredCount,
CurrentRate and PulseInterval) are also reset to zero.
• Counts are lost and outputs are turned off.
Counter 0 in this
example equates
to individual
counter reset
selection bit 12.
(1) This applies only to the 1769-HSC/B module and the CMX 5370 L2 packaged controller embedded HSC.
(2) If zero is outside the MinCount and MaxCount limits set in the configuration array, then the Preset value is
loaded into CurrentCount instead of zero. This also causes the PresetWarning bit to be set, which, in turn, sets
the GenError bit.
IMPORTANT
For most predictable results, clear the output image of the
controller before performing a counter reset (CtrReset) to the
1769-HSC module.
This is because CtrReset does not change the controller’s output
image. CtrReset sets the 1769-HSC module’s output array to all
zeroes. If any bit is set to 1 in the controller’s output image when
sent to the module, it will be seen as a state transition and be
acted upon.