Feedback devices - Revision history

Tero K: serial da

2017-05-10T11:31:27Z

serial da

Tero K: /* Resolver a.k.a. synchro */

2015-05-03T12:24:29Z

‎Resolver a.k.a. synchro

Tero K: /* See also */

2014-03-04T14:56:52Z

‎See also

WikiAdmin at 09:53, 2 May 2012

2012-05-02T09:53:05Z

Tero K at 14:57, 18 April 2012

2012-04-18T14:57:30Z

Tero K: /* Feedback device types */

2012-04-18T14:54:05Z

‎Feedback device types

Tero K: /* Comparison */

2012-04-18T13:12:07Z

‎Comparison

Tero K at 13:10, 18 April 2012

2012-04-18T13:10:30Z

Tero K at 12:29, 18 April 2012

2012-04-18T12:29:36Z

130.230.150.235 at 12:14, 18 April 2012

2012-04-18T12:14:16Z

@@ Line 10: / Line 10: @@
 [[Quadrature]] encoders are nowadays the most common feedback device type in servo motors. Quadrature encoders are incremental sensors so they require position zeroing/homing to get absolute position feedback.
-Another type of encoder is ''absolute encoder''. Absolute encoders typically output serial data of absolute position thus they may not need to be zeroed (in case of multiturn absolute encoders). The drawback of absolute sensors is typically higher price and lower compatibility & interchangeability.
+Another type of encoder is ''absolute encoder''. Absolute encoders typically output serial data of absolute position thus they may not need to be zeroed (in case of multiturn absolute encoders). The drawback of absolute sensors is typically higher price and lower compatibility & interchangeability. For supported absolute encoder devices and user guide, see [[Using serial data feedback device]].
 *[[Wikipedia:Rotary encoder]]
@@ Line 38: / Line 38: @@
 | Absolute encoder
 | Medium
-| Serial, [http://en.wikipedia.org/wiki/Gray_code Gray signals]
+| Serial ([[Using SSI encoder|SSI]], [[Using BiSS encoder|BiSS]], EnDat etc), or parallel [http://en.wikipedia.org/wiki/Gray_code Gray signals]
 | Yes (single or multiturn)
 | Medium to very high

@@ Line 16: / Line 16: @@
 Resolver is an analog technology based on rotary transformer that can provide absolute position (single turn absolute, for multiturn absolute position zeroing is still needed). Resolvers are good for harsh conditions but they don't provide as high precision feedback data as encoders.
-*[[Wikipedia:Synchro]]
+*More info: [[Wikipedia:Synchro]]
 ===Tachometer===
 Tachometer is a small DC generator that outputs DC voltage proportional to rotation speed. It can be used as velocity feedback device but not as position sensor. Tachometers are often seen in dual-loop configurations combined with position sensor.

@@ Line 66: / Line 66: @@
 *[[Motor types]]
 *[[Resolution of motors]]
 [[Category:Hardware]]

@@ Line 65: / Line 65: @@
 ==See also==
 *[[Motor types]]
 [[Category:Hardware]]

@@ Line 11: / Line 11: @@
 Another type of encoder is ''absolute encoder''. Absolute encoders typically output serial data of absolute position thus they may not need to be zeroed (in case of multiturn absolute encoders). The drawback of absolute sensors is typically higher price and lower compatibility & interchangeability.
-===Resolver/synchro===
 Resolver is an analog technology based on rotary transformer that can provide absolute position (single turn absolute, for multiturn absolute position zeroing is still needed). Resolvers are good for harsh conditions but they don't provide as high precision feedback data as encoders.
 ===Tachometer===
 Tachometer is a small DC generator that outputs DC voltage proportional to rotation speed. It can be used as velocity feedback device but not as position sensor. Tachometers are often seen in dual-loop configurations combined with position sensor.

@@ Line 10: / Line 10: @@
 [[Quadrature]] encoders are nowadays the most common feedback device type in servo motors. Quadrature encoders are incremental sensors so they require position zeroing/homing to get absolute position feedback.
-Another type of encoder is ''absolute encoder''. Absolute encoders typically output serial data of absolute position thus they may not need to be zeroed. The drawback of absolute sensors is higher price and lower compatibility & interchangeability.
+Another type of encoder is ''absolute encoder''. Absolute encoders typically output serial data of absolute position thus they may not need to be zeroed (in case of multiturn absolute encoders). The drawback of absolute sensors is typically higher price and lower compatibility & interchangeability.
 ===Resolver/synchro===
-Resolver is an analog technology based on rotary transformer that can provide absolute position (single turn absolute, for multiturn absolute position zeroing is still needed). Resolvers are good for harsh conditions but don't provide as high precision as encoders.
+Resolver is an analog technology based on rotary transformer that can provide absolute position (single turn absolute, for multiturn absolute position zeroing is still needed). Resolvers are good for harsh conditions but they don't provide as high precision feedback data as encoders.
 ===Tachometer===
-Tachometer is a small DC generator that outputs DC voltage proportional to rotation speed. It can be used as velocity feedback device but not as position sensor. Tachometers are often seen in dual-loop configurations with position sensor.
+Tachometer is a small DC generator that outputs DC voltage proportional to rotation speed. It can be used as velocity feedback device but not as position sensor. Tachometers are often seen in dual-loop configurations combined with position sensor.
 ===Hall sensors===
-Hall sensors are found in AC & BLDC motors only. Halls provide commutation information (drive current phase angle) for drive. Modern drives such as all GD drives don't require Hall sensors but can utilize them to make faster power-up possible. Hall sensors are too low resolution for position or high performance velocity control.
+Hall sensors are typically found in AC & BLDC motors only. Halls provide commutation information (drive current phase angle) for drive. Modern drives such as all GD drives don't require Hall sensors but can utilize them to make faster power-up possible. Hall sensors are too low resolution for position or high performance velocity control and that's why Hall sensors are typically combined with encoder.
 ==Comparison==
 {| class="wikitable"

@@ Line 54: / Line 54: @@
 | Digital outputs
 | Yes (single turn)
-| Low
+| Very low
-| Low
+| Very low
 |}

@@ Line 37: / Line 37: @@
 |-
 | Resolver
-| High
+| Very high
 | Analog, 6 wires
 | Yes (single turn)
@@ Line 44: / Line 44: @@
 |-
 | Tachometer
-| Medium
+| Medium to high
 | Analog
 | Yes (for velocity FB)
@@ Line 51: / Line 51: @@
 |-
 | Hall
-| Medium
+| Medium to high
 | Digital outputs
 | Yes (single turn)

← Older revision		Revision as of 12:29, 18 April 2012
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		+	[[File:Servomotor and feedback.png\|thumb\|Typical servo motor with encoder feedback]]
	Feedback devices are mandatory part in [[closed loop]] systems and typically found in servo motor applications. In motion control FB devices are used to get position or velocity information from motor or machine.		Feedback devices are mandatory part in [[closed loop]] systems and typically found in servo motor applications. In motion control FB devices are used to get position or velocity information from motor or machine.
	==Shapes==		==Shapes==

@@ Line 1: / Line 1: @@
-Feedback devices are mandatory part in [[closed loop]] systems thus typically found in servo motor applications. In motion control FB devices are used to get position or velocity information from motor or machine.
+Feedback devices are mandatory part in [[closed loop]] systems and typically found in servo motor applications. In motion control FB devices are used to get position or velocity information from motor or machine.
 ==Shapes==
 Feedback devices come mainly in two shapes: