Difference between revisions of "Setpoint signal"

From Granite Devices Knowledge Wiki
Jump to: navigation, search
[quality revision][quality revision]
(Reference signal characteristics)
(4 intermediate revisions by the same user not shown)
Line 5: Line 5:
 
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 5.0 could mean that motor is asked to produce 5 Nm torque.
 
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 5.0 could mean that motor is asked to produce 5 Nm torque.
 
==Physical reference signal types==
 
==Physical reference signal types==
Reference signals may have several representations in real world including:
+
Reference signals may have several representations in real world such as:
 
* [[Analog reference]] signal
 
* [[Analog reference]] signal
 
* [[Pulse and direction]] signals
 
* [[Pulse and direction]] signals
Line 11: Line 11:
 
* 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 reference as velocity reference, the relation betveen input to output types could be 1 Volt per 100 rpm (or any other scale).
 +
==Reference signal characteristics==
 +
{| class="wikitable"
 +
|-
 +
!  !! Analog !! Pulse & dir !! PWM !! Serial
 +
|-
 +
| Scale & range || Absolute (limited) || Incremental (infinite) || Absolute (limited) ||
 +
*Absolute (near infinite)
 +
*Incremental (infinite)
 +
|-
 +
| Reference uses in motion control || Torque, velocity || Position, velocity || Torque, velocity || Position, torque, velocity
 +
|-
 +
| Pros
 +
|| 
 +
* Widely used
 +
* Easy to measure
 +
||
 +
*Widely used
 +
*Exact
 +
*Noise robust
 +
||
 +
*EMI noise robust
 +
*Precise
 +
||
 +
*High resolution & accuracy
 +
*Reduce wiring
 +
*More functions than just reference
 +
|-
 +
|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
 +
|}

Revision as of 14:40, 27 March 2012

Reference signal is a signal that will be used as target value in control systems. Typical occurrencies of reference signals in GD products are:

  • Position reference
  • Veloicty reference
  • Torque reference

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 5.0 could mean that motor is asked to produce 5 Nm torque.

Physical reference signal types

Reference 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 reference as velocity reference, the relation betveen input to output types could be 1 Volt per 100 rpm (or any other scale).

Reference signal characteristics

Analog Pulse & dir PWM Serial
Scale & range Absolute (limited) Incremental (infinite) Absolute (limited)
  • Absolute (near infinite)
  • Incremental (infinite)
Reference uses in motion control Torque, velocity Position, velocity Torque, velocity Position, torque, velocity
Pros
  • Widely used
  • Easy to measure
  • Widely used
  • Exact
  • Noise robust
  • EMI noise robust
  • Precise
  • High resolution & accuracy
  • Reduce wiring
  • More functions than just reference
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