Optical Shaft Encoder
R2026bRepresent connected Optical Shaft Encoder and read relative position of motor shaft in ticks
Optical Shaft Encoder block
To add a block to a model, double-click the canvas and start typing the block name. Then, select the block from the list.
Libraries:
Simulink Coder Support Package for VEX EDR V5 Robot Brain /
Sensors
Description
Add-On Required: This feature requires the Simulink Coder Support Package for VEX EDR V5 Robot Brain add-on.
The Optical Shaft Encoder block represents an Optical Shaft Encoder that is connected to the 3-wire ports of VEX EDR V5 Robot Brain, and reads the relative position of the motor shaft in ticks. The value increments for anti-clockwise rotation and decrements for clockwise rotation of the motor shaft.
The tick count also depends on the Reset mode that you selected.
Ports
Input
Output
Parameters
If you are using a 3-Wire Expander, specify the smart port on VEX® EDR V5 Robot Brain to which the expander is connected.
Select the 3-wire port of VEX V5 Robot Brain to which the top port of Optical Shaft Encoder is connected. To know the top port, click the What is Top and Bottom Port? button.
After you select the Top port in the block, the consecutive
3-wire port is assumed to be connected to the bottom port of the encoder. For example,
if you select A as the Top port, it is
assumed that B is connected to the bottom port of the
encoder.
Select the reset mode for reading values from the Optical Shaft Encoder.
When you select Reset by external signal, an additional
input – Rst – is added to the block, which can be connected to a
reset signal.
The different reset modes this block supports are as follows:
No reset– The measurement value is not reset and the block outputs the total ticks of rotation.For example, in the table below at T = 1, the encoder moves a tick count of 20 in anti-clockwise direction and therefore the output is 20. Between T = 1 and T = 2, the encoder moves a tick count of 10.
Therefore, the tick count is 30 at T = 2 ( 20 from T = 1 and 10 from T = 2). In this reset mode, the output at any time instant is a cumulative sum of the previous count and the current count.
Reset at each sample time– For each sample period, the block outputs the measurement value and then resets it to 0.For example, in the table below, at T = 1, the encoder moves a tick count of 20 in anti-clockwise direction and therefore the output is 20. Between T = 1 and T = 2, the encoder moves a tick count of 10 and therefore the output is 10. In this reset mode, the output is the tick count at a particular time instant.
Reset by external signal– The measurement value is reset to 0 based on the block input value. When you send a value other than 0 to the block input, the measurement value is reset to 0. For each sample period, the block outputs the measurement value since the last reset.For example in the table below, when the external signal is 0, the output is based on ‘No reset’ mode and when the external signal is non-zero, the output is based on ‘Reset at each sample time’ mode.
Enter the time interval at which the block reads values from the Optical Shaft Encoder.
When you set this parameter to -1, Simulink® determines the best sample time for the block based on the block context
within the model. If you select Reset by external signal
option in Reset mode parameter, the Sample
time parameter is hidden and the value is inherited (Sample time =
-1).
Programmatic Use: Add Block
To add the block programmatically, use the add_block function with one of these library block paths as the source.
"vexv5lib/Sensors/Optical Shaft Encoder"
Example: add_block("vexv5lib/Sensors/Optical Shaft Encoder","myModel/myBlock",MakeNameUnique="on")
Extended Capabilities
Version History
Introduced in R2019b
