| 蒋 晶， 蒋东方， 高 航 |
（西北工业大学 自动化学院，陕西 西安 710072） |
 摘要：针对目前增量式光电编码器辨向计数电路脉冲或抖动干扰抑制能力差的问题，提出了一种基于有限状态机的编码器接口电路设计方案，并给出了硬件实现。首先将光电编码器输出的A、B两路信号在每个脉冲周期内的电平变化细分为4个子段，总结出正、反向旋转时A、B信号电平的正常变化规律，并引入有限状态机方法进行描述；再利用状态机机制，检测出光电编码器输出的信号的各种有效、错误和无效状态，同时正确输出转速计数脉冲、旋转方向、出错报警3路信号，以满足高准确度和高容错性计数的要求，增强角位置测量系统的可靠性；最后介绍了采用EPROM完成状态机时序电路实现的具体方法。 |
| 关键词：角位置/速率测量系统；增量式光电编码器；辨向计数电路；有限状态机；抖动抑制 |
| 中图分类号：TP212 文献标识码：A 文章编号：1000-8829(2009)02-0001-04 |
| A High Accuracy Interface Circuit Design for Incremental Photoelectric Encoder |
| JIANG Jing, JIANG Dong-fang, GAO Hang |
| (College of Automation,Northwestern Polytechnical University, Xian 710072, China) |
| Abstract：To overcome the shortcomings such as low tolerance in pulse disturbance and shaking rotating error rejection existed in current interface circuit for incremental photo-electric encoder,a finite-state machine based encoder interface circuit design and its implementation is proposed.The encoder outputted A,B signals within every pulse cycle are divided into four sub-segment,their translating laws in positive and negative rotating direction are extracted and described with finitestate machine at first.Latter,with help of state-machine,normal encoder pulse,rotate direction,error state/invalid state are detected from the encoder signals.Three output signals are generated respectively for satisfying high accuracy and high error tolerance pulse counting,angle position measurement requirement.The EEPROM based implementation of the state-machine is introduced at last. |
| Key words：angle position/velocity measurement system；incremental photoelectric encoder；direction recognition and pulse counting circuit；finite state machine；shaking rejection |
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