Rockwell Automation 1769-HSC Compact High Speed Counter Module - Manual (Page 80)

80 Rockwell Automation Publication 1769-UM006E-EN-P - July 2013
Chapter 4 Module Configuration, Output, and Input Data
Counter Hysteresis (CtrnHysteresis)
The hysteresis value is the number of counts that should be disregarded in the
calculation of the cyclic rate. If the count value changes by less than the hysteresis
value, the rate is reported as zero, regardless of the actual rate at which the pulses
are counted.
Counter Scalar (CtrnScalar)
This value is used to scale the Rate value. The Rate value is divided by the Scalar
value. The default value is 1 for counters 0 and 1. The default value is 0 for
counters 2 and 3.
Ctr
nScalar can be used to determine RPM. To configure the Ctr[n].CurrentRate
value to show an RPM value, set Ctr
nScalar to (counts per revolution)/60.
See page 34 for more information.
IMPORTANT The Counter Hysteresis information does not apply to the L23E packaged
controller because rate measurement is not supported.
Configuration Array Words 15 14 13 12 11 10 09 08 07 06 05 04 03 02 01 00
12 Counter 0 Hysteresis Ctr0Hysteresis
22 Counter 1 Hysteresis Ctr1Hysteresis
32 Counter 2 Hysteresis Ctr2Hysteresis
42 Counter 3 Hysteresis Ctr3Hysteresis
IMPORTANT Do not change this value while the counter is enabled. Attempting to do
so will result in a BadModConfigUpdate error. See
page 120 for a list
of prohibited settings.
IMPORTANT The Counter Scalar information does not apply to the L23E packaged
controller because rate measurement is not supported.
Configuration Array Words 15 14 13 12 11 10 09 08 07 06 05 04 03 02 01 00
13 Counter 0 Scalar Ctr0Scalar
23 Counter 1 Scalar Ctr1Scalar
33 Counter 2 Scalar Ctr2Scalar
43 Counter 3 Scalar Ctr3Scalar
IMPORTANT For any counter being used, do not set Scalar to a value less than one or
a configuration error will occur.