Instruction Manual
Table Of Contents
- 1769-UM006E-EN-P, Compact High-speed Counter Module User Manual
- Summary of Changes
- Table of Contents
- Preface
- 1 - Module Overview
- 2 - Module Operation
- 3 - Installation and Wiring
- 4 - Module Configuration, Output, and Input Data
- Configure the Module
- Configuration Array
- General Configuration Bits
- Filter Selection
- Program Mode and Program State Run
- Output Program Value (Out0ProgramValue through Out3ProgramValue)
- Output Fault Mode and Output Fault State Run
- Output Fault Value (Out0FaultValue through Out3FaultValue)
- Counter Maximum Count (CtrnMaxCount)
- Counter Minimum Count (CtrnMinCount)
- Counter Preset (CtrnPreset)
- Counter Hysteresis (CtrnHysteresis)
- Counter Scalar (CtrnScalar)
- Cyclic Rate Update Time (CtrnCyclicRateUpdateTime)
- Configuration Flags
- Range High Limit (Range0To11[n].HighLimit) and Range Low Limit (Range0To11[n].LowLimit)
- Range Output Control (Range0To11[n].OutputControl)
- Range Configuration Flags
- Output Array
- Output on Mask (OutputOnMask.0 through OutputOnMask.15)
- Output Off Mask (OutputOffMask.0 through OutputOffMask.15)
- Range Enable (RangeEn.0 through RangeEn.15)
- RBF - Reset Blown Fuse (ResetBlownFuse)
- Control Bits
- Range High Limit or Direct Write Value (Range12To15[n].HiLimOrDirWr)
- Range Low Limit (Range12To15[n].LowLimit)
- Range Output Control (Range12To15[n].OutputControl)
- Range Configuration Flags (12To15)
- Input Array
- Input State (InputStateA0 through InputStateZ1)
- Readback (Readback.0 through Readback.15)
- Status Flags
- Range Active (RangeActive.0 through RangeActive.15)
- Current Count (Ctr[n].CurrentCount)
- Stored Count (Ctr[n].StoredCount)
- Current Rate (Ctr[0].CurrentRate to Ctr[3].CurrentRate)
- Pulse Interval (Ctr[0].PulseInterval and Ctr[1].PulseInterval)
- Status Flags
- 5 - Diagnostics and Troubleshooting
- A - Specifications
- B - Program a 1769-HSC Module, CompactLogix Controller, and 845F Incremental Encoder with RSLogix 5000 Software
- C - Program a 1769-HSC Module, MicroLogix 1500 Controller, and 845F Incremental Encoder with RSLogix 500 Software
- D - Programming Quick Reference
- E - History of Changes
- Glossary
- Index
- Back Cover
Rockwell Automation Publication 1769-UM006E-EN-P - July 2013 33
Module Operation Chapter 2
The generalized rate calculation is Rate = count/ time.
The cyclic method is better suited to high pulse rates.
Hysteresis Detection and Configuration
Because physical vibration can cause an encoder to generate pulses that you do
not wish to consider as valid motion, a hysteresis value is used to eliminate a
certain number of pulses in either direction as vibration-generated. These pulses
are not used to calculate the Ctr[n].CurrentRate value. You program the
minimum number of counts that are considered to be valid motion, using the
CtrnHysteresis configuration word/menu. If the change in counts over the
update time cycle is equal to or less than the minimum number of programmed
counts, the Ctr[n].CurrentRate is reported as zero.
This concept is not used to alter actual count values.
IMPORTANT
The rate calculation is based on net counts. If a counter goes up 500
counts and down 300 counts, the net count is 200. Therefore, changes in
direction and speed affect the Ctr[n].CurrentRate value.
IMPORTANT
Hysteresis does not depend on the direction of the change in count.
Therefore, creeping, a slow change in count in one direction only, can
also be reported as zero frequency when it falls below the hysteresis
threshold.