Rockwell Automation 1756-HSC ControlLogix High Speed Counter Module - Manual (Page 26)

Rockwell Automation Publication 1756-UM007C-EN-P - November 2011
26 Counter Modes
Outputs
The module has four outputs, isolated in pairs (0 and 1, 2 and 3). Each output
is capable of sourcing current from an externally supplied voltage up to
30V DC. You must connect an external power supply to each of the output
pairs. The outputs can source 1 A DC and are hardware-driven. They turn On
or Off in less than 50 s when the appropriate count value has been reached.
Assign Outputs to Counters
By using configuration tags or the RSLogix 5000 software defaults, you can
assign the outputs on the module to any of the various counters. You can
assign as many as two outputs to a given counter. However, an output may be
assigned only once to a counter; it’s not possible to use the same output with
two different counters.
Each output on the 1756-HSC module can be turned On and Off at your
discretion. The operation of outputs tied to a counter (on the Output
Configuration tab of the Module Properties dialog box) are performed
independently from the controller scans.
Output Operation
When the outputs for the module are enabled and assigned to a counter, they
operate in an On-Off fashion. Up to two On-Off windows may be used for
each output. The outputs use a comparison of the Present Value to the values
you have programmed in one or both of the following tags:
• First Value Output Turns On and First Value Output Turns OFF
• Second Value Output Turns ON and Second Value Output Turns OFF
IMPORTANT
You have the option of selecting either the rising or falling edge
of the gate/reset pulse. When the Invert Z Value box is checked
on the Counter Configuration tab, the state of the Z input is
reversed as illustrated in the four Store modes.
For example, in the Store and Reset, and Start mode using the
Invert Z, the falling edge of the pulse on Input Z will store the
count value in the Stored Value tag and reset the Present Value
tag to zero. The counter continues to count while the gate pin is
low or high, but the present value is reset to zero (0) on the next
falling edge of Input Z.