Design Features

The Ensemble® Epaq is Aerotech’s next-generation, stand-alone controller for moderate- to high-performance applications. It offers functionality appropriate for applications from basic laboratory experimentation and general purpose positioning to advanced OEM systems at an affordable price.

Versatile, Stand-Alone, Multi-Axis Control

The Ensemble Epaq is offered in a 6-axis desktop (rack-mount optional) version with display and jog pad. It contains integrated power supplies and pluggable motor and IO connectors. PWM amplifiers are offered to control brush, brushless, and stepper motors. Linear amplifiers are also available for high performance, low noise applications. Higher power external amplifiers may be daisy-chained to the Epaq using the high-speed AeroNet serial interface for a total of nine axes of coordinated motion.

This flexible configuration style allows users to seamlessly mix and match drive types (linear versus PWM, brush or brushless, stepper, etc.) within the same positioning system using a common programming and control platform.

Multiple Epaqs can be controlled from one Windows® PC through Ethernet or USB. Optional on-board encoder interpolation offers the user programmable axis resolution (assuming a sine-wave encoder input signal), including the ability to change interpolation (multiplication) values through software.

Powerful and Intuitive Programming Functionality

Multiple Axis ControlUnlike most controllers on the market today, there is no need to understand a cryptic command set to generate motion. The intuitive interface allows a user to begin programming immediately. Ensemble online help further simplifies writing motion programs and includes many functional examples that can be easily modified for customer applications.

The Ensemble with Integrated Development Environment software offers a graphical user interface in Windows®, featuring an intuitive Program Editor, Variable Output window, Compiler Output window, and Task State monitor. This interface enables users to easily monitor all aspects of their positioning system, no matter how complex. The Axis Control and Diagnostic screens are further supplemented by a fully functional Autotuning utility that minimizes startup time and allows easy optimization of motion axes. System diagnostics are easily read from the interface. The Windows-based remote software package is included with each unit, which allows the user to /upload/download programs, modify parameter files, and analyze motion with Aerotech’s advanced graphical tuning package, all from the convenience of a remote PC.

Whether operated in stand-alone mode through the front panel or by remote control through Ethernet or USB, the full functionality of the Ensemble Epaq is available. On-board configuration and monitoring utilities simplify remote communications. To allow easy serial connectivity and ease of use, the Epaq features an RS-232 port (additional RS-232 port is an option).

Integrated Amplifier Electrical SpecificationsMPML
Output VoltageVDC24 V, 48 V, 54 V, 90 V options10-40 V (Bipolar)
Peak Output CurrentA1010(1)
Continuous Output CurrentA55(1)
PWM Switching FrequencykHz20N/A
Power Amplifier BandwidthkHzSoftware SelectableSoftware Selectable
Minimum Load InductancemH0.1 @ 54 VDC0
Operating Temperature°C0 to 500 to 50
Storage Temperature°C-20 to 85-20 to 85
Weightkg0.50.5
  1. Actual current ratings dependent on motor resistance.

Advanced DSP Control

The Ensemble Epaq uses the processing power of multiple double precision, floating-point DSPs to offer exceptional performance in a variety of applications, including point-to-point motion, linear and circular interpolation, single- and multi-axis error correction, direct commutation of linear and rotary brushless servomotors, and on-board servo autotuning. High-speed interrupts and data logging capabilities provide a real-time link to external systems. The Ensemble Epaq also offers high-speed position latching capability and optional single-axis PSO (Position Synchronized Output). Whether the requirement is simple point-to-point motion or complex velocity profiled contours with output on the fly, Ensemble ensures peak performance for critical applications.

Integral Drives

Brushless servo, DC brush servo, and microstepping drives are integrated into the Ensemble Epaq compact frame. The Epaq can control any combination of up to six integral drives, while the Ensemble architecture is capable of further expansion (with external stand-alone, single-axis drive units) to up to nine total axes. Because the Epaq can control many different types of motors, customers have excellent flexibility in their system designs. High accuracy linear motor air-bearings can be controlled from the same controller running lower precision drives with servo or stepper motors. Parameters are easily reconfigured for these various motors and feedback devices, so customers can adapt to changing system needs.

Expanded Input/Output Capability

Each Epaq features an optional second RS-232 port, and an axis expansion port. On a per axis basis the Epaq also features an optional I/O package offering eight digital inputs and outputs, one 12-bit ±10 VDC analog input, one 16-bit ±5 VDC output, a configurable brake output, a second TTL encoder input for dual loop control, and either a second marker input or PSO output. This optional I/O package can be added to each axis so numerous I/O can be connected to the Epaq.

Enhancing a Legacy of Success

Although Ensemble is envisioned as a general-purpose, stand-alone controller, it carries forward a legacy of success built from Aerotech’s hugely successful A3200 and Soloist™ controllers. It offers enhanced capabilities that make it an ideal choice for many aggressive motion control applications. The Ensemble motion control architecture builds upon the Soloist intuitive graphical user interface, while offering advanced features appropriate for multi-axis control. Pre-coded LabVIEW® VIs, AeroBasic™ programming functionality, MATLAB® library, .NET tools for C#, VB.NET and C++/CLI or C make the Ensemble even easier to use. See the Ensemble Control home page for detailed information on software capabilities and ordering options.

Allen-Bradley Interface

Combine proven PLC with proven motion control for easier integration, startup, and maintenance of medium- and high-end automation projects. The Aerotech EtherNet/IP™ interface enables AB PLCs (MicroLogix, CompactLogix™,or ControlLogix) to be integrated directly with the Ensemble. Motion can be directly programmed in the RSLogix 5000 environment or separate programs can be written on the controller and triggered from the AB PLC. Aerotech has two interfaces: ASCII and Register. Choose the PLC, motion controller, and interface that best fits your application needs.

EPICS Drivers

Each Ensemble installation includes full compatibility with the EPICS open source distributed control system. EPICS is used worldwide at leading light source (synchrotron) facilities and other government laboratories, allowing Ensemble to seamlessly integrate into applications at all major research institutions.

Specifications

Ensemble Epaq Specifications

FeatureUnitsDescription
Number of Axes
1 to 6
Encoder Inputs
1 to 6
Motor Style
Brush, Brushless, Stepper
Power SupplyVAC100/115/200/230 VAC; 50/60 Hz (Factory Configured)
Bus VoltageVDC40, 40LP, 80, 80LP, 10B, 20B, 30B, 40B
Peak Output Current (1 sec)(1)Apk10
Continuous Output Current(1)Apk5
Digital Inputs
No
Digital Outputs
No
Analog Inputs
One 16-bit Analog Input per Axis
Analog Outputs
No
Dedicated Axis I/O on Feedback Connector
Three Limit Inputs (CW, CCW, Home); Three Hall Effect Inputs (A, B, C); Three High-Speed Differential Inputs (sin, cos, mkr for encoder); Motor Over-Temperature Input; One 16-bit Analog Input
Dedicated I/O on Auxiliary Feedback Connector
sin, cos, mkr for Aux Enc; Aux Enc can be used for PSO Output
I/O Expansion Board(2)
One 12-bit Differential Analog Input; One 16-bit Analog Output; Eight Digital Inputs, Optically Isolated, Sinking or Sourcing; Eight Optically Isolated Digital Outputs per Axis
High Speed Data Capture
Yes(2)
High Speed Digital Outputs
No
BiDirectional Lines
No
Automatic Brake Control
Optional
Emergency Stop (ESTOP)
Optional
Position Synchronized Output (PSO)
Single Axis Standard
Can Output Multiplied Encoder
Yes (only with MXH option)
Can Output Square Wave Encoder
Yes
Primary Encoder Input Frequency with Multiplication
200 kHz (MXU) or 450 kHz (MXH) sine wave
Primary Encoder Input Frequency Square Wave
10 MHz square wave frequency/40 MHz count rate
Secondary Encoder Input Frequency
10 MHz square wave frequency/40 MHz count rate
Laser Feedback Support
No
Encoder Multiplication(3)
x4096 (MXU); x65536 (MXH)
Resolver Interface
No
Internal Shunt Resistor
No
External Shunt
No
Ethernet
Yes
USB
Yes
RS-232
Yes
FireWire
No
Fieldbus
Modbus TCP on PC
Joystick
Yes
Additional Interfaces
10/100 Base T Ethernet communication interface for system setup, application networking, Epaq-to-Epaq communications, embedded programming, immediate commands, and Modbus over TCP; USB communication interface for system setup, application networking, Windows® PC control interface; RS-232 port with programmable baud rate, length, parity, stop bits (second RS-232 port optional)

ESTOP to Stop All Axes

Display: Backlit 8 x 40 Character LCD

Keypad: 5-Key Input Pad
Current Loop Update RatekHz20
Servo Loop Update RatekHz1 to 20
Power Amplifier BandwidthkHzSelectable Through Software
Minimum Load InductancemH0.1 mH with PWM; 0 with Linear
Operating Temperature°C0 to 50
Storage Temperature°C-30 to 85
Weightkg (lb)10 (22)
Package
Desktop or Rackmount
Standards
CE approved, 2011/65/EU RoHS 2 Directive
  1. Peak value of the sine wave; rms current for AC motors is 0.707 * Apk.

  2. Requires I/O option.

  3. Effective multiplication factor after quadrature decoding (if applicable).

Dimensions

Ordering Information

Ordering Example

Ensemble Epaq-S/A40/1-MP10I/2-MP10/3-MP10/4-MP10/5-MP10/6-MP10

/US-115VAC/Brake-2/RS232-2

Ordering Options

BasePackageLine 
Voltage
Bus Power 
Supply
Axis 1 
Amp
Axis 2 
Amp
Axis 3 
Amp
Axis 4 
Amp
Axis 5 
Amp
Axis 6 
Amp
Ensemble Epaq-S
-R
/A 
/B 
/C 
/D
40 
40LP 
80 
80LP 
10B 
20B 
30B 
40B
/1-MP10I 
/1-MP10MI 
/1-ML10I 
/1-ML10MI 
/1-ML10HI
/2-MP10 
/2-MP10I 
/2-MP10M 
/2-MP10MI 
/2-BLANK 
/2-BLANKW 
/2-ML10 
/2-ML10I 
/2-ML10MI 
/2-ML10M 
/2-ML10HI
/2-ML10H
/3-MP10 
/3-MP10I 
/3-MP10M 
/3-MP10MI 
/3-BLANK 
/3-BLANKW 
/3-ML10 
/3-ML10I 
/3-ML10MI 
/3-ML10M 
/3-ML10HI
/3-ML10H
/4-MP10 
/4-MP10I 
/4-MP10M 
/4-MP10MI 
/4-BLANK 
/4-BLANKW 
/4-ML10 
/4-ML10I 
/4-ML10MI 
/4-ML10M 
/4-ML10HI
/4-ML10H
/5-MP10 
/5-MP10I 
/5-MP10M 
/5-MP10MI 
/5-BLANK 
/5-BLANKW 
/5-ML10 
/5-ML10I 
/5-ML10MI 
/5-ML10M 
/5-ML10HI
/5-ML10H
/6-MP10 
/6-MP10I 
/6-MP10M 
/6-MP10MI 
/6-BLANK 
/6-BLANKW 
/6-ML10 
/6-ML10I 
/6-ML10MI 
/6-ML10M 
/6-ML10HI
/6-ML10H

Line CordBrake OptionsOptions
/ENGLAND 
/GERMANY 
/ISRAEL 
/AUSTRALIA 
/INDIA 
/US-115VAC 
/US-230VAC 
/NOLINECORD
/Brake-1
/Brake-2
/Brake-3
/Brake-4
/Brake-5
/Brake-6
/ESTOP0 
/ESTOP1 
/EXTAMP 
/SLIDE 
/RS232-2

Epaq

OptionDescription
Epaq-SSix axis, desktop, stand-alone motion controller with integrated power supplies, and servo/stepping motor amplifiers. Features include independent or coordinated motion, point to point, linear and circular interpolation, constant velocity, velocity profiled, time based, free-run motion types, electronic gearing, backlash compensation, and 1D or 2D axis calibration. Ensemble Standard HMI Multi-Axis Software included.
  • Up to 10 kHz servo update rate for all axes

  • Digital servo loop

  • One 10/100 base T Ethernet port, one USB 2.0 port, one RS-232 port

  • Dedicated I/O per axis includes: CW, CCW, and home limits, marker, Hall effect sensors, enable, fault, for each axis

  • User defined I/O includes eight opto-isolated inputs (sinking or sourcing), eight outputs (sinking or sourcing), one 12-bit analog input, one 16-bit analog output and brake relay; this I/O is on Axis 1; optional adder for axes 2-6

Epaq-RSix axis, rack-mount, stand-alone motion controller with integrated power supplies, and servo/stepping motor amplifiers. Features include independent or coordinated motion, point to point, linear and circular interpolation, constant velocity, velocity profiled, time based, free-run motion types, electronic gearing, backlash compensation, and 1D or 2D axis calibration. Ensemble Standard HMI Multi-Axis Software included.
  • Up to 10 kHz servo update rate for all axes

  • Digital servo loop

  • One 10/100 base T Ethernet port, one USB 2.0 Port, one RS-232 port

  • Dedicated I/O per axis includes: CW, CCW, and home limits, marker, Hall effect sensors, enable, fault, for each axis

  • User defined I/O includes eight opto-isolated inputs (sinking or sourcing), eight outputs (sinking or sourcing), one 12-bit analog input, one 16-bit analog output and brake relay; this I/O is on Axis 1; optional adder for axes 2-6

Standard or Blank Front Panel (must select one)

OptionDescription
-FPBBlank front panel (without display or keypad)
-FPDStandard front panel (with display and keypad)
-FPBEBlank front panel with ESTOP switch (without display or keypad)
-FPDEStandard front panel with ESTOP switch (with display and keypad)

Line Voltage (must select one)

OptionDescription
/A115 VAC line voltage
/B230 VAC line voltage
/C100 VAC line voltage
/D200 VAC line voltage

Bus Power Supply

OptionDescription
4040 VDC motor supply, 600 W
40LP40 VDC motor supply, 300 W
8080 VDC motor supply, 600 W
80LP80 VDC motor supply, 300 W
10B±10 VDC bipolar motor supply, 400 W
20B±20 VDC bipolar motor supply, 400 W
30B±30 VDC bipolar motor supply, 400 W
40B±40 VDC bipolar motor supply, 600 W

Axis 1 Amplifier Options (must select one)

OptionDescription
/1-MP10IDigital PWM amplifier, 10 A peak, 5 A continuous with I/O option
/1-MP10MIDigital PWM amplifier, 10 A peak, 5 A continuous; x4096 MXU(1) with I/O option
/1-ML10IDigital linear amplifier, 10 A peak, 5 A continuous with I/O option
/1-ML10MIDigital linear amplifier, 10 A peak, 5 A continuous; x4096 MXU(1) with I/O option
/1-ML10HIDigital linear amplifier, 10 A peak, 5 A continuous; x65536 MXH(1) with I/O option
  1. Effective multiplication factor specified after quadrature decoding (if applicable).

Axis 2 Amplifier Options (must select one)

OptionDescription
/2-MP10Digital PWM amplifier, 10 A peak, 5 A continuous
/2-MP10IDigital PWM amplifier, 10 A peak, 5 A continuous with I/O option
/2-MP10MDigital PWM amplifier, 10 A peak, 5 A continuous; x4096 MXU(1)
/2-MP10MIDigital PWM amplifier, 10 A peak, 5 A continuous; x4096 MXU(1) with I/O option
/2-BLANKNo amplifier
/2-BLANKWNo amplifier, pre-wired only
/2-ML10Digital linear amplifier, 10 A peak, 5 A continuous
/2-ML10IDigital linear amplifier, 10 A peak, 5 A continuous with I/O option
/2-ML10MDigital linear amplifier, 10 A peak, 5 A continuous; x4096 MXU(1)
/2-ML10MIDigital linear amplifier, 10 A peak, 5 A continuous; x4096 MXU(1) with I/O option
/2-ML10HDigital linear amplifier, 10 A peak, 5 A continuous; x65536 MXH(1)
/2-ML10HIDigital linear amplifier, 10 A peak, 5 A continuous; x65536 MXH(1) with I/O option
  1. Effective multiplication factor specified after quadrature decoding (if applicable).

Axis 3 Amplifier Options (must select one)

OptionDescription
/3-MP10Digital PWM amplifier, 10 A peak, 5 A continuous
/3-MP10IDigital PWM amplifier, 10 A peak, 5 A continuous with I/O option
/3-MP10MDigital PWM amplifier, 10 A peak, 5 A continuous; x4096 MXU(1)
/3-MP10MIDigital PWM amplifier, 10 A peak, 5 A continuous; x4096 MXU(1) with I/O option
/3-BLANKNo amplifier
/3-BLANKWNo amplifier, pre-wired only
/3-ML10Digital linear amplifier, 10 A peak, 5 A continuous
/3-ML10IDigital linear amplifier, 10 A peak, 5 A continuous with I/O option
/3-ML10MDigital linear amplifier, 10 A peak, 5 A continuous; x4096 MXU(1)
/3-ML10MIDigital linear amplifier, 10 A peak, 5 A continuous; x4096 MXU(1) with I/O option
/3-ML10HDigital linear amplifier, 10 A peak, 5 A continuous; x65536 MXH(1)
/3-ML10HIDigital linear amplifier, 10 A peak, 5 A continuous; x65536 MXH(1) with I/O option

Axis 4 Amplifier Options (must select one)

OptionDescription
/4-MP10Digital PWM amplifier, 10 A peak, 5 A continuous
/4-MP10IDigital PWM amplifier, 10 A peak, 5 A continuous with I/O option
/4-MP10MDigital PWM amplifier, 10 A peak, 5 A continuous; x4096 MXU(1)
/4-MP10MIDigital PWM amplifier, 10 A peak, 5 A continuous; x4096 MXU(1) with I/O option
/4-BLANKNo amplifier
/4-BLANKWNo amplifier, pre-wired only
/4-ML10Digital linear amplifier, 10 A peak, 5 A continuous
/4-ML10IDigital linear amplifier, 10 A peak, 5 A continuous with I/O option
/4-ML10MDigital linear amplifier, 10 A peak, 5 A continuous; x4096 MXU(1)
/4-ML10MIDigital linear amplifier, 10 A peak, 5 A continuous; x4096 MXU(1) with I/O option
/4-ML10HDigital linear amplifier, 10 A peak, 5 A continuous; x65536 MXH(1)
/4-ML10HIDigital linear amplifier, 10 A peak, 5 A continuous; x65536 MXH(1) with I/O option
  1. Effective multiplication factor specified after quadrature decoding (if applicable).

Axis 5 Amplifier Options (must select one)

OptionDescription
/5-MP10Digital PWM amplifier, 10 A peak, 5 A continuous
/5-MP10IDigital PWM amplifier, 10 A peak, 5 A continuous with I/O option
/5-MP10MDigital PWM amplifier, 10 A peak, 5 A continuous; x4096 MXU(1)
/5-MP10MIDigital PWM amplifier, 10 A peak, 5 A continuous; x4096 MXU(1) with I/O option
/5-BLANKNo amplifier
/5-BLANKWNo amplifier, pre-wired only
/5-ML10Digital linear amplifier, 10 A peak, 5 A continuous
/5-ML10IDigital linear amplifier, 10 A peak, 5 A continuous with I/O option
/5-ML10MDigital linear amplifier, 10 A peak, 5 A continuous; x4096 MXU(1)
/5-ML10MIDigital linear amplifier, 10 A peak, 5 A continuous; x4096 MXU(1) with I/O option
/5-ML10HDigital linear amplifier, 10 A peak, 5 A continuous; x65536 MXH(1)
/5-ML10HIDigital linear amplifier, 10 A peak, 5 A continuous; x65536 MXH(1) with I/O option

Axis 6 Amplifier Options (must select one)

OptionDescription
/6-MP10Digital PWM amplifier, 10 A peak, 5 A continuous
/6-MP10IDigital PWM amplifier, 10 A peak, 5 A continuous with I/O option
/6-MP10MDigital PWM amplifier, 10 A peak, 5 A continuous; x4096 MXU(1)
/6-MP10MIDigital PWM amplifier, 10 A peak, 5 A continuous; x4096 MXU(1) with I/O option
/6-BLANKNo amplifier
/6‑BLANKWNo amplifier, pre-wired only
/6-ML10Digital linear amplifier, 10 A peak, 5 A continuous
/6-ML10IDigital linear amplifier, 10 A peak, 5 A continuous with I/O option
/6-ML10MDigital linear amplifier, 10 A peak, 5 A continuous; x4096 MXU(1)
/6-ML10MIDigital linear amplifier, 10 A peak, 5 A continuous; x4096 MXU(1) with I/O option
/6-ML10HDigital linear amplifier, 10 A peak, 5 A continuous; x65536 MXH(1)
/6-ML10HIDigital linear amplifier, 10 A peak, 5 A continuous; x65536 MXH(1) with I/O option
  1. Effective multiplication factor specified after quadrature decoding (if applicable).

Line Cord (must select one)

OptionDescription
/ENGLANDUK compatible line cord
/GERMANYGerman compatible line cord
/ISRAELIsrael compatible line cord
/INDIAIndia compatible line cord
/AUSTRALIAAustralia compatible line cord
/US-115VACUS 115 VAC line cord
/US-230VACUS 230 VAC line cord
/NO-LINECORDNo line cord

Brake Options (up to 2 selections allowable)

OptionDescription
/BRAKE-1Axis 1 wired for 24 V, 1 A brake
/BRAKE-2Axis 2 wired for 24 V, 1 A brake (amp must have “I” or “MI” option)
/BRAKE-3Axis 2 wired for 24 V, 1 A brake (amp must have “I” or “MI” option)
/BRAKE-4Axis 2 wired for 24 V, 1 A brake (amp must have “I” or “MI” option)
/BRAKE-5Axis 2 wired for 24 V, 1 A brake (amp must have “I” or “MI” option)
/BRAKE-6Axis 2 wired for 24 V, 1 A brake (amp must have “I” or “MI” option)

Options (multiple selections allowable)

OptionDescription
/ESTOP0Provides user with a mushroom switch on front panel to stop motion, disable, and disconnect AC to motor power supply; requires -FPDE or -FPBE options
/ESTOP1Controller stops motion, then disables servo control; internal positive guided relay with monitor contact disconnects AC power source from motor; operator risk assessment is the responsibility of the end user or integrator; not compatible with -FPBE or FPDE; user must provide external ESTOP switch and wiring to the Epaq
/EXTAMPExternal amplifier interface connector
/SLIDERack-mount slides to be used with Epaq-R
/RS232-2Second RS-232 interface port

Standard Motor Power and Combination Power/Feedback Cables (order as separate line items)

OptionDescription
C21481-50CABLE: BL MTR-4TS-4MS-LP1-MAX450DM: MS motor power cable; Epaq 4-terminal connector to 4-pin MS connector; 5 A continuous current; 5 meters long
C21491-50CABLE: BL MTR-4TS-4DU-LP1-MAX450DM: HPD motor power cable; Epaq 4-terminal connector to 4-pin high power D connector; 5 A continuous current; 5 meters long
C21511-50CABLE: BL MTR-4TS-4DU-LP1-HF-MAX450DM: Hi Flex HPD motor power cable; Epaq 4 terminal connector to 4-pin High Power D connector; 5 A continuous current; 5 meters long
C21501-50CABLE: BL MTR & FB-4TS-25DU-25DU-MAX107DM: 25-pin D stage to split Epaq 4-terminal strip motor power and 25D feedback cable; 5 meters long
C21521-50CABLE: SM MTR & FB-25DU-4TS-23B-MAX107DM: 23-pin stepper motor connector to split Epaq 4-terminal strip motor power and 25D feedback cable; 5 meters long
C22091-50Motor power cable, high flex, 5.0 meters long, for use with Epaq; 4 A continuous current rating, to be used with 10 A peak drives ONLY
  • Motor type: brushless

  • Motor/stage connector: 4-pin high power D

  • Amplifier connector: 4-pin terminal strip Epaq connector

  • Maximum cable length: 45 meters

  • Minimum bend radius 60 mm (2.36")

  • Rated for continuous flex

  • BL MTR-FLB-4DU-HF60-4ARMS-MAX 450DM

Accessories

OptionDescription
/JBVJoystick with 5 ft cable
/JIIndustrial joystick with 5 ft cable

Integration (Required)

Aerotech offers both standard and custom integration services to help you get your system fully operational as quickly as possible. The following standard integration options are available for this system. Please consult Aerotech if you are unsure what level of integration is required, or if you desire custom integration support with your system.

OptionDescription
-TASIntegration - Test as system
Testing, integration, and documentation of a group of components as a complete system that will be used together (ex: drive, controller, and stage). This includes parameter file generation, system tuning, and documentation of the system configuration.
-TACIntegration - Test as components
Testing and integration of individual items as discrete components that ship together. This is typically used for spare parts, replacement parts, or items that will not be used together. These components may or may not be part of a larger system.