Rockwell Automation 1746-HSCE,D17466.5 High-Speed Counter Module - Manual (Page 25)

Publication 1746-UM006B-EN-P - August 2005
Module Operation 2-7
Input Pulse Counter The module’s input pulse counter has the ability to count input pulses
at a rate of up to 50k Hz. Several types of channel A and B input
configurations are supported as discussed previously. The resulting
Accumulated Count value is available in the module’s Input Data File.
Counter Types
The module provides two types of counter operation, ring and linear.
The selection is made by the Counter Type bit (M0:e.1/13) as follows:
Counter Type - bit 13
Linear Counter
The figure below demonstrates linear counter operation. In linear
operation the count value must remain in the range of -32767 to
+32767. If the count value goes above +32767 or below -32767, a
linear counter overflow/underflow error results. This condition is
indicated by a 1 in the Over/Underflow bit (I:e.0/13). This is a critical
error that halts operation of the module. Refer to Linear Counter
Overflow/Underflow in Chapter 5.
The linear counter can be configured to reset to a nonzero value
through the reset parameter.
Counter Type Bit (bit 13) Counter Type
0 Linear
1 Ring
Setup and Control Word, Word 1
Bit Number (decimal) 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Counter Type
M0:e.1
Underflow Overflow
–32,767 +32,767
Count Up
0
Count Down
Counter Value