Difference between revisions of "Setpoint signal"

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Reference signal is a signal that will be used as ''target value'' in control systems. Typical occurrences of reference signals in GD procuts are:
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[[File:Setpoint and actual.png|thumb|400px|An example setpoint signal (target value) and measured response signal (realized output value) of a control system.]]
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* Position reference
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Setpoint (a.k.a reference) signal is a signal that will be used as ''target value'' in control systems. Typical occurrencies of setpoint signals in GD products are:
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* Veloicty reference
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* Position setpoint
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* Torque reference
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* Velocity setpoint
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I.e. position reference value may be "1234" which could mean a target position of 1234 mm in some linear actuator. Or torque reference of 5 Nm would mean that motor is asked to produce 5 Nm torque.
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* Torque setpoint
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==Physical reference signal types==
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I.e. position setpoint value may be "1234" which could mean a target position of 1234 mm in some linear actuator. Or torque setpoint of 5.0 could mean that motor is asked to produce 5 Nm torque.
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In practice, reference signals may have several representations in real world including:
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==Physical setpoint signal types==
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* Analog voltage signal
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Setpont signals may have several representations in real world such as:
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* [[Analog setpoint]] signal
 
* [[Pulse and direction]] signals
 
* [[Pulse and direction]] signals
 
* [[PWM]] signal
 
* [[PWM]] signal
 
* Serial communication command
 
* Serial communication command
  
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In these cases there will be a conversion between input and output units. For example when using +/-10V reference as velocity reference, the relation betveen types could be 1 Volt per 100 rpm (or any other scale).
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In these cases there will be a conversion between input and output units. For example when using +/-10V as velocity setpoint, the relation between input to output types could be 1 Volt per 100 rpm (or any other scale).
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==Setpoint signal characteristics==
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{| class="wikitable"
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|-
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!  !! [[Analog setpoint|Analog]] !! [[Pulse and direction|Pulse & dir]] or [[Quadrature]] !! [[PWM]] !! Serial / Network
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|-
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| Scale & range || Absolute (limited) || Incremental (infinite) || Absolute (limited) ||
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*Absolute (near infinite)
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*Incremental (infinite)
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|-
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| Setpoint uses in motion control || Torque, velocity || Position, velocity || Torque, velocity || Position, torque, velocity, parameters
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|-
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| Pros
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|| 
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* Widely used
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* Easy to measure
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*Widely used
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*Exact
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*Noise robust
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||
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*EMI noise robust
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*Precise
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*High resolution & accuracy
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*Reduce wiring
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*More functions than just setpoint
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|-
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|Cons
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||
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*EMI noise sensitive
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*Offset & gain errors
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*Limited resolution at low frequency
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*Need reference zeroing because incremental
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*Various "standards", sometimes incompatible
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*Many standards
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*Usually incompatible with other standards
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|}
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[[Category:Signals]]
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[[Category:Glossary]]

Latest revision as of 19:59, 28 August 2015

An example setpoint signal (target value) and measured response signal (realized output value) of a control system.

Setpoint (a.k.a reference) signal is a signal that will be used as target value in control systems. Typical occurrencies of setpoint signals in GD products are:

  • Position setpoint
  • Velocity setpoint
  • Torque setpoint

I.e. position setpoint value may be "1234" which could mean a target position of 1234 mm in some linear actuator. Or torque setpoint of 5.0 could mean that motor is asked to produce 5 Nm torque.

Physical setpoint signal types[edit | edit source]

Setpont signals may have several representations in real world such as:

In these cases there will be a conversion between input and output units. For example when using +/-10V as velocity setpoint, the relation between input to output types could be 1 Volt per 100 rpm (or any other scale).

Setpoint signal characteristics[edit | edit source]

Analog Pulse & dir or Quadrature PWM Serial / Network
Scale & range Absolute (limited) Incremental (infinite) Absolute (limited)
  • Absolute (near infinite)
  • Incremental (infinite)
Setpoint uses in motion control Torque, velocity Position, velocity Torque, velocity Position, torque, velocity, parameters
Pros
  • Widely used
  • Easy to measure
  • Widely used
  • Exact
  • Noise robust
  • EMI noise robust
  • Precise
  • High resolution & accuracy
  • Reduce wiring
  • More functions than just setpoint
Cons
  • EMI noise sensitive
  • Offset & gain errors
  • Limited resolution at low frequency
  • Need reference zeroing because incremental
  • Various "standards", sometimes incompatible
  • Many standards
  • Usually incompatible with other standards
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