Allen-Bradley Rockwell Automation 857 User Manual page 8

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Table of Contents
Chapter 5
Measurement Functions
Chapter 6
Control Functions
857-UM001A-EN-P - July 2009
Measurement Accuracy ...........................................................5-1
RMS Values ............................................................................ 5-2
RMS Currents ................................................................... 5-2
RMS Voltages .................................................................. 5-2
Harmonics and Total Harmonic Distortion (THD) ................. 5-3
Demand Values ....................................................................... 5-3
Minimum and Maximum Values ............................................ 5-4
Maximum Values of the last 31 days and 12 months ............. 5-5
Voltage Measurement Mode ................................................... 5-5
Power Calculation ................................................................... 5-6
Device Connected to Line-to-Line Voltages .................... 5-6
Device Connected to Line-to-Neutral Voltages ............... 5-7
Direction of Power and Current .............................................. 5-8
Symmetric Components .......................................................... 5-9
Primary, Secondary and Per Unit Scaling ............................ 5-12
Current Scaling ............................................................... 5-12
Per Unit [pu] Scaling ...................................................... 5-13
Voltage Scaling ..................................................................... 5-15
Per Unit [pu] Scaling of Line-to-Line Voltages ............. 5-16
Output Relays ..........................................................................6-1
Digital Inputs .......................................................................... 6-2
Virtual Inputs and Outputs ...................................................... 6-4
Output Matrix ......................................................................... 6-5
Blocking Matrix ...................................................................... 6-6
Controllable Objects ............................................................... 6-6
Object States ..................................................................... 6-7
Basic Settings for Controllable Objects ........................... 6-7
Output Signals of Controllable Objects ........................... 6-7
Settings for Read-only Objects ........................................ 6-8
Controlling with DI .......................................................... 6-8
Local/Remote Selection ................................................... 6-8
Auto-Reclose Function (79) ................................................... 6-9
Manual Closing .............................................................. 6-10
Manual Opening ............................................................. 6-10
Reclaim Time Setting ..................................................... 6-10
Support for 2 Circuit Breakers ....................................... 6-11
Blocking of AR Shots .................................................... 6-11
Starting AR Sequence .................................................... 6-11
Starting Sequence at Shot 2-5 & Skipping of AR Shots .... 6-11
Critical AR Request ....................................................... 6-12
Shot Active Matrix Signal .............................................. 6-12
AR Running Matrix Signal ............................................ 6-12
Final Trip Matrix Signals ............................................... 6-12
DI to Block AR Setting .................................................. 6-12
AR Info for Mimic Display Setting ................................ 6-12
Logic Functions .................................................................... 6-16