Difference between revisions of "Setpoint signal"

From Granite Devices Knowledge Wiki
Jump to: navigation, search
[unchecked revision][checked revision]
m (Text replacement - "{{param|PWM}}" to "PWM")
 
(24 intermediate revisions by 5 users not shown)
Line 1: Line 1:
Reference signal is a signal that will be used as ''target value'' in control systems. Typical occurrences of reference signals in GD products are:
+
[[File:Setpoint and actual.png|thumb|400px|An example setpoint signal (target value) and measured response signal (realized output value) of a control system.]]
* Position reference
+
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:
* Veloicty reference
+
* Position setpoint
* Torque reference
+
* Velocity setpoint
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.
+
* Torque setpoint
==Physical reference signal types==
+
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.
In practice, reference signals may have several representations in real world including:
+
==Physical setpoint signal types==
* Analog voltage signal
+
Setpont signals may have several representations in real world such as:
 +
* [[Analog setpoint]] signal
 
* [[Pulse and direction]] signals
 
* [[Pulse and direction]] signals
 
* [[PWM]] signal
 
* [[PWM]] signal
 
* Serial communication command
 
* Serial communication command
  
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).
+
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==
 +
{| class="wikitable"
 +
|-
 +
!  !! [[Analog setpoint|Analog]] !! [[Pulse and direction|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
 +
|}
 +
[[Category:Signals]]
 +
[[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