Document Outline

• DECS-250N
• Preface
• Contents
• Introduction
  • Features and Functions
  • Applications
  • Package
  • Optional Features and Capabilities
    • Style Number
  • Storage
    • Electrolytic Capacitor Considerations
• Controls and Indicators
  • Front Panel Illustration and Description
  • Menu Navigation
  • Adjusting Settings
  • Display Setup
    • LCD
    • Sleep Mode
    • Language
    • Screen Scrolling
• Power Inputs
  • Control Power
  • Operating Power
• Power Stage
  • Field Transient Protection
  • Inverting Style Excitation System Compatibility
• Voltage and Current Sensing
  • Generator Voltage
  • Generator Current
    • Phase Sensing
    • Cross-Current Compensation
  • Bus Voltage
• Synchronizer
  • Generator Synchronization
    • Frequency Correction
    • Voltage Correction
    • Angle Compensation
    • Failure of Synchronization
  • Voltage Matching
  • Breaker Hardware Configuration
    • Breaker Failure
    • Generator Breaker
  • Generator and Bus Condition Detection
    • Generator Condition
    • Generator Stability
    • Bus Condition
    • Bus Stability
  • Generator Governor Control
• Regulation
  • Regulation Modes
    • AVR
    • FCR
    • FVR
    • Var
    • Power Factor
  • Pre-Position Setpoints
  • Transient Boost
  • Operation with Paralleled Generators
    • Reactive Droop Compensation
    • Cross-Current Compensation
    • Network Load Sharing
    • Line Drop Compensation
  • Autotracking
    • Internal Setpoint Tracking
    • External Setpoint Tracking
  • Setpoint Configure
• Auxiliary Control
  • Auxiliary Control Input Type
  • Auxiliary Control Input Function
    • PSS Test Input
    • Limiter Scaling
    • Setpoint Limits
  • Auxiliary Control Gains
    • AVR Mode
    • FCR Mode
    • FVR Mode
    • Var Mode
    • Power Factor Mode
  • Summing Type
• Contact Inputs and Outputs
  • Contact Inputs
    • Start and Stop Inputs
    • Programmable Inputs
  • Contact Outputs
    • Watchdog Output
    • Programmable Outputs
• Protection
  • Voltage Protection
    • Overexcitation (Volts per Hertz)
  • Frequency Protection
    • Underfrequency
  • Power Protection
    • Reverse Power
    • Loss of Excitation
  • Field Protection
    • Field Overvoltage
    • Exciter Diode Monitor
    • Power Input Failure
  • Sync-Check Protection
  • Generator Frequency Less Than 10 Hertz
  • Configurable Protection
• Limiters
  • Overexcitation Limiter
    • Summing Point OEL
    • Takeover OEL
  • Underexcitation Limiter
  • Stator Current Limiter
    • Low-Level Limiting
    • High-Level Limiting
    • Initial Delay
  • Var Limiter
  • Limiter Scaling
  • Underfrequency Limiter
    • Volts per Hertz
• Metering
  • Metering Explorer
    • HMI
    • BESTCOMSPlus®
      • Metering Screen Docking
  • Metered Parameters
    • Generator
    • Power
    • Bus
    • Field
    • PSS
    • Synchronization
    • Auxiliary Control Input
    • Tracking
    • Control Panel
    • Metering Summary
  • Status Indication
    • System Status
    • Inputs
      • DECS-250N Contact Inputs
      • CEM-2020 Contact Inputs
      • AEM-2020 Inputs
    • Outputs
      • DECS-250 Contact Outputs
      • CEM-2020 Contact Outputs
      • AEM-2020 Analog Outputs
    • Network Load Share
    • Configurable Protection
    • Alarms
      • Alarm Configuration
      • User-Programmable Alarms
      • Retrieving Alarm Information
      • Resetting Alarms
    • Real-Time Clock
  • Auto Export Metering
• Event Recorder
  • Sequence-of-Events Recording
  • Data Logging
    • Setup
  • Trending
• Power System Stabilizer
  • Supervisory Function and Setting Groups
    • Supervisory Function
    • Setting Groups
  • Theory of Operation
    • Speed Signal
    • Rotor Frequency Calculation
    • Generator Electrical Power Signal
    • Derived Mechanical Power Signal
    • Stabilizing Signal Selection
    • Torsional Filters
    • Phase Compensation
    • Washout Filter and Logic Limiter
    • Output Stage
    • Terminal Voltage Limiter
• Stability Tuning
  • AVR Mode
    • Predefined Stability Settings
    • Custom Stability Settings
      • PID Calculator
    • Auto Tuning
  • FCR and FVR Modes
    • FCR Mode Stability Settings
    • FVR Mode Stability Settings
  • Other Modes and Functions
    • Var Mode
    • Power Factor Mode
    • Overexcitation Limiter (OEL)
    • Underexcitation Limiter (UEL)
    • Stator Current Limiter (SCL)
    • Var Limiter
    • Voltage Matching
• Mounting
  • Mounting Considerations
  • Projection Mounting
  • Behind-the-Panel Mounting
• Terminals and Connectors
  • Overview
  • Terminal Types
• Typical Connections
• BESTCOMSPlus® Software
  • General Description
  • Installation
    • Install BESTCOMSPlus®
  • Activation of the DECS-250N Plugin for BESTCOMSPlus®
    • Connect a USB Cable
    • Start BESTCOMSPlus® and Activate DECS-250N Plugin Automatically
    • Manual Activation of the DECS-250N Plugin
    • Establishing Communication
  • Menu Bars
    • Upper Menu Bar (BESTCOMSPlus® Shell)
    • Lower Menu Bar (DECS-250N Plugin)
  • Settings Explorer
  • Metering Explorer
  • Settings File Management
    • Opening a Settings File
    • Saving a Settings File
    • Upload Settings and/or Logic to Device
    • Download Settings and Logic from Device
    • Printing a Settings File
    • Comparing Settings Files
  • Automatic Metering Export
  • Firmware Updates
    • Upgrading Firmware in Expansion Modules
    • Upgrading Firmware in the DECS-250N
  • BESTCOMSPlus® Updates
• BESTlogic™Plus
  • Introduction
  • Overview of BESTlogic™Plus
    • BESTlogic™Plus Composition
  • Logic Schemes
    • The Active Logic Scheme
    • Sending and Retrieving Logic Schemes
    • Default Logic Schemes
  • Programming BESTlogic™Plus
    • Pickup and Dropout Timers
  • Offline Logic Simulator
  • BESTlogic™Plus File Management
    • Saving a BESTlogicPlus File
    • Opening a BESTlogicPlus File
    • Protecting a BESTlogicPlus File
    • Uploading a BESTlogicPlus File
    • Downloading a BESTlogicPlus File
    • Copying and Renaming Preprogrammed Logic Schemes
    • Printing a BESTlogicPlus File
    • Clearing the On-Screen Logic Diagram
  • BESTlogic™Plus Examples
    • Example 1 - GOVR Logic Block Connections
    • Example 2 - AND Gate Connections
• Communication
  • Local Communication
  • Communication with a Second DECS
  • Modbus™ Communication
    • RS-485 Port
    • Ethernet Port
  • CAN Communication
    • Connections
    • Port Configuration
    • Remote Module Setup
  • Ethernet Communication
    • Ethernet Connection
  • PROFIBUS Communication
• Configuration
  • Generator, Field, and Bus Ratings
  • Sensing Transformer Ratings and Configuration
    • Generator PT
    • Generator CTs
    • Bus PT
    • Operating Power Input
    • Modes of Operation
      • Firing Pulse Mode
      • Single-Phase Selection
    • Rated Frequency
    • Maximum Over-Speed
    • Soft Start
    • Field Flashing
  • Device Information
    • Firmware and Product Information
      • Firmware Information
      • Product Information
    • Device Identification
  • Display Units
• Security
  • Password Access
    • Password Creation and Configuration
  • Port Security
    • Port Access Configuration
  • Login and Access Controls
    • Access Timeout
    • Login Failure
• Timekeeping
  • Time and Date Format
  • Daylight Saving Time Adjustments
  • Network Time Protocol (NTP)
    • NTP Settings
  • IRIG
• Testing
  • Real-Time Metering Analysis
    • Graph Parameters
  • Frequency Response
    • Test Mode
    • Bode Plotting
    • Transfer Function
    • Frequency Response
  • Time Response
    • Signal Input
    • Test Signal Characteristics
  • Step Response Analysis
    • AVR, FCR, and FVR Tabs
    • Var and PF Tabs
  • Analysis Options
    • Layout Tab
    • Graph Display Tab
• CAN Communication
  • Introduction
  • CAN Parameters
    • Diagnostic Trouble Codes (DTCs)
• Modbus™ Communication
  • Introduction
    • Message Structure
      • Device Address Field
      • Function Code Field
      • Data Block Field
      • Error Check Field
  • Modbus Modes of Operation
    • Modbus™ Over Serial Line
      • Message Structure
      • Message Framing and Timing Considerations
    • Modbus on TCP/IP
      • Application Data Unit
      • MBAP Header Description
    • Error Handling and Exception Responses
    • DECS-250N Modbus™ via Ethernet
  • Detailed Message Query and Response for RTU Transmission Mode
    • Read Holding Registers
      • Query
      • Response
    • Return Query Data
    • Restart Communications Option
    • Listen Only Mode
    • Preset Multiple Registers
      • Query
      • Response
    • Preset Single Register
      • Query
      • Response
  • Data Formats
    • Floating Point Data Format (Float)
    • Long Integer Data Format (Uint32)
    • Integer Data Format (Uint16) or Bit-Mapped Variables in Uint16 Format
    • Short Integer Data Format/Byte Character Data Format (Uint8)
    • String Data Format (String)
    • CRC Error Check
  • Secure DECS-250N Login via Modbus
  • Modbus Parameters
    • General
    • Security
    • Binary Points
    • Metering
    • Limiters
    • Setpoints
    • Global Settings
    • Relay Settings
    • Protection Settings
    • Gains Settings
    • Legacy Modbus
• PROFIBUS Communication
  • Data Types
    • Float/UINT32
    • UINT8
    • Example 1: Bit Packing Order for Instance 8
    • Example 2: Bit Packing Order for Instance 11
  • Setup
  • PROFIBUS Parameters
• Maintenance
  • Storage
  • Preventive Maintenance
    • Connections
    • Electrolytic Capacitors
  • Cleaning the Front Panel
  • Troubleshooting
    • DECS-250N Appears Inoperative
    • Display Blank or Frozen
    • Generator Voltage Does Not Build
    • Low Generator Voltage in AVR Mode
    • High Generator Voltage in AVR Mode
    • Generator Voltage Unstable (Hunting)
    • Protection or Limit Annunciation
    • HMI Meter Readings Incorrect
    • No Communication
    • DECS-250N Reboots Frequently
  • Support
• Specifications
  • Operating Power
  • Control Power
  • Generator and Bus Voltage Sensing
  • Generator Current Sensing
  • Accessory Inputs
  • Contact Inputs
  • Communication Ports
  • IRIG Time Synchronization Input
  • Contact Outputs
  • Field Power Output
    • Maximum Positive Forcing Voltage
    • Maximum Negative Forcing Voltage
  • Parallel Compensation
  • Generator Protection Functions
    • Overvoltage (59) and Undervoltage (27)
    • Loss of Sensing
    • Overfrequency (81O) and Underfrequency (81U)
    • Reverse Power (32R)
    • Loss of Excitation (40Q)
    • Field Overvoltage
    • Field Overcurrent
    • Loss of PMG
    • Exciter Diode Monitor (EDM)
    • Voltage Difference
    • Slip Angle
    • Slip Frequency
  • Startup
    • Soft Start Level
    • Soft Start Time
    • Field Flash Dropout Level
    • Maximum Field Flash Time
  • Voltage Matching
  • On-Line Overexcitation Limiting
    • High Current Level
    • Medium Current Level
    • Low Current Level
  • Off-Line Overexcitation Limiting
    • High Current Level
    • Low Current Level
  • Sequence of Events Recording (SER)2
  • Data Logging (Oscillography)
  • Environment
    • Temperature
    • Humidity
    • Salt Fog
  • Type Tests
    • Shock
    • Vibration
    • Impulse
    • Transients
    • Static Discharge
    • Radio Interference
    • HALT (Highly Accelerated Life Testing)
  • Patent
  • Physical
  • Regulatory Standards
    • Maritime Recognition
    • UL Approval
    • CSA Certification
    • CE Compliance
    • EAC Mark (Eurasian Conformity)
• Analog Expansion Module
  • General Information
  • Features
  • Specifications
    • Operating Power
    • Analog Inputs
    • RTD Inputs
    • Thermocouple Inputs
    • Analog Outputs
    • Communication Interface
      • CAN Bus
    • Type Tests
      • Shock
      • Vibration
      • HALT (Highly Accelerated Life Testing)
    • Environment
    • UL Approval
    • CSA Certification
    • CE Compliance
    • Physical
  • Installation
    • Mounting
    • Connections
      • Terminations
      • Operating Power
      • AEM-2020 Inputs and Outputs
      • External Analog Input Connections
      • External RTD Input Connections
      • CAN Bus Interface
  • Communications
  • Functional Description
    • Analog Inputs
    • RTD Inputs
    • Thermocouple Inputs
    • Analog Outputs
  • Metering
    • Analog Inputs
    • RTD Inputs
    • Thermocouple Inputs
    • Analog Input Values
    • Analog Outputs
  • Maintenance
    • Firmware Updates
• Contact Expansion Module
  • General Information
  • Features
  • Specifications
  • Installation
  • Communications
  • Functional Description
  • Metering
  • Maintenance
• Revision History