Rotary Encoder board datasheet EB

Transcription

1 Rotary Encoder board datasheet EB CONTENTS 1. About this document General Information Board layout Testing this product Circuit description.. 4 Appendix 1 Circuit diagram. Copyright 2011 Matrix Multimedia Limited 1

2 1. About This Document This document concerns the Matrix Multimedia Rotary Encoder board, order code EB Trademarks and copyright PIC and PICmicro are registered trademarks of Arizona Microchip Inc. E-blocks is a trademark of Matrix Multimedia Limited. EB073 and associated software and documentation are Copyright 2011 Matrix Multimedia Limited. 2. Other Sources of Information There are various other documents and sources that you may find useful: Getting Started with E-Blocks.pdf This describes the E-block system and how it can be used to develop complete systems for learning electronics and for PICmicro programming. PPP Help File This describes the PPP software and its functionality. PPP software is used for transferring hex code to a PICmicro microcontroller. C and Assembly Strategies For strategy information for creating C and Assembly code for the Quad relay board see members area. This can be found at 3. Disclaimer The information provided within this document was correct at the time of going to press. Matrix Multimedia reserves the right to change specifications from time to time. 4. Technical Support If you have any problems operating this product then please refer to the troubleshooting section of this document first. You will find the latest software updates, FAQs and other information on our web site: Copyright 2011 Matrix Multimedia Limited 2

3 1. General information The board features two rotary encoders, a standard digital switch and an output LED. The rotary encoders each have two digital outputs in a quadrature format that can be read by the upstream microcontroller. The quadrature format means that the microcontroller can detect which way the encoder is turning, how fast and how many rotations have been made simply by monitoring the two signals from the encoder. 1. Features 2 x Rotary encoders with full quadrature outputs Digital Switch and LED onboard 3.3V and 5V compatible E-blocks compatible 2. Connections The patch system on the board is used to allow the onboard signals to be connected through to any of the 8 digital channels or through to another board or port. The connections for the patch jumper system are as shown below. Signal DEFAULT Port Pin PATCH Pin J5 Encoder 1A Pin4 A1 Encoder 1B Pin5 B1 Encoder 2A Pin6 A2 Encoder 2B Pin7 B2 Switch Pin0 SW LED Pin1 LED Copyright 2011 Matrix Multimedia Limited 3

4 E-blocks TM Rotary Encoder board Rotary Encoder board layout Downstream 9-way D type connector. Patch system Screw Terminals Signal Bias resistors Low pass filter 1 Rotary encoder 1 LED Switch Low pass filter 2 Rotary encoder 2 Copyright 2011 Matrix Multimedia Limited 4

5 4. Testing This Product The following instructions describe the test procedure for the EB Rotary Encoder board. 1. System Setup Multi-programmer board (EB-006) with: EB006 Options Power supply PICmicro device SW1 (Fast/Slow) SW2 (RC/Xtal) Xtal frequency Port B Port D Test program Setting External, 14V 16F877A Don t care Xtal MHz Rotary Encoder Board EB073 LCD Board EB005 Encoder.HEX 2. Test procedure Connect EB073 (Rotary Encoder board) to PORTB of the Multiprogrammer. Connect EB005 (LCD board) to PORTD of the Multiprogrammer. Ensure EB073 jumper settings are in the default position. Connect a wire from the +V screw terminal of the Multi-programmer to +V terminal of Encoder board. Connect a wire from the +V screw terminal of the Multi-programmer to +V terminal of LCD board. Connect USB cable to computer and EB006. Ensure 13.5V power supply is working correctly and connect to EB006. Open PPP. In PPP open file Encoder.HEX. In PPP click on Send To PICmicro icon. A pop up window will inform you of status. If status is ok a Program Sent And Verified window will be observed on the screen The LEDs will display count values for encoder channels 1 and 2. Turn the rotary encoders one at a time and ensure that the appropriate count value changes in relation to the rotation on the encoder. Press the switch on the board and ensure that the LED switches off while the switch is pressed. If the counters are changing correctly and the switch and LED are working then the board has passed the test routine. Copyright 2011 Matrix Multimedia Limited 5

6 5. Circuit Description The EB073 Rotary Encoder circuit can be observed in Appendix1. 1. Quadrature Encoders Quadrature encoders have two digital outputs (A and B), which indicate the current phase of the rotational shaft. As the encoder shaft is turned the phase increments or decrements depending on the direction of rotation. By monitoring the encoder output phase it is possible to detect which direction the shaft is rotating and by counting how many complete phases have occurred it is possible to detect how many rotations have occurred in a single direction. Absolute position is not available when using a quadrature encoder unless you have some means of defining an absolute position such as an input from an end stop switch. Diagram showing the four unique phases of a quadrature encoder output. 2. Interrupt On Change (PORT) Using a port change interrupt it is possible to reliably count encoder phase changes on a microcontroller without having to sit in a tight loop repeatedly sampling the encoder output pins V Operation The board is fully compatible for use with 5V and 3.3V systems. Copyright 2011 Matrix Multimedia Limited 6

7 E-blocks TM Rotary Encoder board Appendix 1 Circuit diagram Copyright 2011 Matrix Multimedia Limited 7