Difference between revisions of "Setpoint signal"
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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 5.0 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 | + | 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:
- Analog reference signal
- Pulse and direction signals
- PWM signal
- 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 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) |
|
| Reference uses in motion control | Torque, velocity | Position, velocity | Torque, velocity | Position, torque, velocity |
| Pros |
|
|
|
|
| Cons |
|
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|
