Laser tacho probe and Panel Tachometers
Laser tacho probe 与面板式转速表选型：接近式与霍尔适合长期固定安装，光电与激光适合便携与特殊场景；反光贴纸作靶标简单但易脏易脱落，面板表可本地显示并输出模拟量。
核心要点
A tachometer is only as good as the pulse it receives. Whether you choose proximity, Hall effect, optical or laser sensing, the goal is the same: one clean pulse per revolution, every revolution, for years. 这篇文章把四种传感器的取舍讲清楚，也说明面板式转速表在其中扮演的角色。
Laser Tacho Probe, Tachometer Sensors, Optical Sensors
Tachometers and Speed Transmitters require permanently mounted speed sensors that observe a target on the machine's rotating shaft. Several types of sensors are available including Proximity, Hall Effect (magnetic), Optical and Laser. Permanently mounted systems usually use a Proximity or Hall Effect type sensor. Laser and Optical Sensors are more suited for portable equipment and special applications. Optical Sensors work well with "Reflective Tape" as a target on the shaft but are not recommended for permanent installation as the sensor may become dirty over time or the tape may come loose.
To create the "speed pulse" required by the Tachometer to calculate RPM, either a Proximity or Hall Effect Sensor is mounted to observe a Keyway or Speed Gear Wheel mounted on the machine's rotating shaft. While Keyways generally create a once-per-turn pulse, speed gears may produce 10, 30, 60 or 100 pulses (teeth) per revolution. For highly accurate and low speed readings, a Speed Gear with multiple pulses per revolution is preferred. For balancing, a "once per turn" pulse is preferred.
Panel Tachometers LUYOR-908 and LUYOR-910
Panel Mount Tachometers are used to measure RPM, measuring conveyor speed, motor speed and many other applications. They can be custom programmed to fit your application. Rugged and reliable, our 1/8 DIN panel mount tachometers are designed for both the OEM and retrofit markets and are suitable for a broad range of applications. From the economical LUYOR-908 to the sophisticated yet affordable LUYOR-910 with optional output modules, panel tachometers are engineered to meet the strictest tolerances.
Laser Tacho Probe, Tachometer Sensors
四种传感器怎么取舍
接近式（Proximity）：靠金属靶标引起涡流变化，无源、耐污、抗干扰，是长期固定安装的常规选择。需要在轴上加工键相槽或安装金属凸台。
霍尔式（Hall Effect）：靠磁场变化，需要安装磁钢。结构简单、成本低，适合中低速与有安装空间的场合。
光电式（Optical）：靠反射光强弱，配反光贴纸作靶标。安装最方便，但长期固定安装不推荐——传感器窗口会积灰，贴纸也可能脱落，导致信号丢失。
激光式（Laser）：光斑小、方向性强、可远距离测量，适合便携设备与特殊应用：被测件不能改装、距离远、空间受限、或需要临时测试。配反光贴纸或反差标记即可工作。
规律很清楚：永久安装优先接近式或霍尔；临时测试、改造受限、远距离测量优先激光或光电。
"速度脉冲"是怎么产生的
无论哪种传感方式，最终都要在轴上形成周期性的"标记—非标记"变化：金属凸台与缺口、磁钢与齿、反光贴与背景、亮标记与暗标记。传感器每次经过标记输出一个脉冲，脉冲频率乘以 60 即得 rpm。
细节决定信号质量：标记宽度不宜超过轴周长的十分之一，太宽会让脉宽比例失真；反光贴要与背景形成足够反差，亮金属面可先涂黑；多标记均布时要在仪表里填写每转脉冲数，否则读数成倍偏差。
面板式转速表的价值
传感器只给脉冲，要变成"看得见的数字"或"能进系统的信号"，还需要显示与转换环节。面板式转速表（Panel Tachometer）承担两件事：
- 本地显示：操作者在设备旁直接读数，不必依赖上位机；
- 信号转换：把脉冲转成 4~20 mA 或 0~5 V 模拟量，送进 PLC、数采或监控系统。
量程可自定义是关键功能。例如测量范围 0~5000 转，可设 0 转输出 0 V、5000 转输出 5 V，这样模拟量与实际转速线性对应，上位机换算简单、分辨率也不浪费。设定一般通过面板按键加密码进入参数菜单完成。
典型接线：传感器棕线接信号端子、黑线接地、蓝线接电源；模拟输出端分正负两极接采集通道。具体端子号按仪表说明书执行，接错可能损坏传感器。
常见问题
长期安装在户外，选哪种？
优先接近式或霍尔，耐污耐候。若必须用光学方式，需加防尘罩并定期清洁窗口。
反光贴纸能长期用吗？
不建议。灰尘、油污会让反射率下降，高温高湿下胶层也会失效。长期监测应改用金属靶标或键相槽。
面板表能替代数采吗？
不能。它提供显示与模拟输出，适合单点监控；需要同步采集、频谱分析时仍要用数采的转速通道。
一台表能接几个传感器？
通常一路输入配一只传感器。多测点需多台仪表，或改用多通道采集系统。
相关产品与延伸阅读
上海路阳仪器有限公司. 《Laser tacho probe and Panel Tachometers》[EB/OL]. 上海路阳仪器有限公司, 2024-10-01. https://www.luyor.net/jishuwenzhang/Laser-tacho-probe.html.
