振动限位开关 LVL-A7
来源：未知 日期：2017/03/21 浏览量：次
限位检测开关在介质达到设定高度、超过设定值或者低于设定值的时候进行切换信号。 设定值(VDI/VDE Directive 3519)基于安装高度。
音叉液/料位测量仪的工作模式：两片音叉在使用中由压电器件振动。在空气中音叉有一个固定振动频率。当遇到液体时，音叉频率和振幅发生改变。电路检测到这些变化并产生开关信号。
在用有振动式限位开关测量限位时，将棒或音叉置于振动中。如果振动探头与介质发生接触，则振动会发生改变，振动式限位开关发出一个开关指令。将振动式限位开关作为溢流保护装置或空载报告器用于液体中以及颗粒状的或粉末状的固料中。
产品特点：● Limit switch for liquids
● External function test with test magnet
● Onsite function check possible thanks to LED indication
● Large selection of process connections for hassle-free installation in existing systems
● Easy to install even at points difficult to access due to compact design
● Rugged stainless steel housing
● Suitable for process temperatures up to 150 °C (302 °F)
● Cost-saving plug connections
● Approval as overfill protection and leak detection system acc. to WHG
| 一般规格： | ||
|---|---|---|
| Measuring method | The tuning fork is brought to its resonance frequency by means of a piezoelectric drive. If the tuning fork is covered by liquid, this frequency changes. The electronics monitor the resonance frequency and indicate whether the tuning fork is freely vibrating or is covered by liquid. | |
| Construction type |
compact device device with short tube |
|
| Operating mode |
MAX = maximum safety: The device keeps the electronic switch closed as long as the liquid level is below the fork. example application: overspill protection MIN = minimum safety: The device keeps the electronic switch closed as long as the fork is immersed in liquid. example application: dry running protection of pumps The electronic switch opens if the limit is reached, if a fault occurs or in the event of a power fails (quiescent current principle) |
|
| Supply： | ||
| Rated voltage |
- DC-PNP: 10 ... 35 V DC, 3-wire - AC/DC: 20 ... 253 V AC/DC, 2-wire |
|
| Current consumption |
- DC-PNP: < 15 mA - AC/DC: < 3.8 mA |
|
| 输入： | ||
| Measured variable | density | |
| Measurement range | min. 0.7 g/cm3, optional> 0.5 g/cm3 | |
| 输出： | ||
| Output type | switch output | |
| Switching current | max. 250 mA | |
| 指令符合： | ||
| Electromagnetic compatibility | ||
| Directive 2014/30/EU | EN 61326-1:2006 , EN 61326-2-3:2006 | |
| Low voltage | ||
| Directive 2014/35/EU | EN 61010-1:2010 | |
| 符合： | ||
| Electromagnetic compatibility | NE 21 | |
| Degree of protection | IEC 60529 | |
| Shock resistance | EN 60068-2-27 | |
| Vibration resistance | EN 60068-2-64 | |
| Climate class | DIN EN 60068-2-38/IEC 68-2-38 | |
| 测量精度： | ||
| Reference operating conditions |
- ambient temperature: 25 °C (+77 °F) - process pressure: 1 bar (14.5 psi) - fluid: water (density: approx. 1 g/cm3, viscosity: 1 mm2/s) - medium temperature: 25 °C (+77 °F) - density setting: > 0.7 g/cm3 - switching time delay: standard (0,5 s, 1 s) |
|
| Measured value resolution | < 0.5 mm | |
| Measuring frequency | approx. 1100 Hz in air | |
| Switching point | 13 mm ± 1 mm | |
| Non-repeatability | ± 1 mm acc. to DIN 61298-2 | |
| Hysteresis | max. 3 mm | |
| Influence of ambient temperature | negligible | |
| Influence of medium temperature | -25 µm/°C | |
| Influence of medium pressure | -20 µm/bar | |
| Switching time |
- 0.5 s when tuning fork is covered - 1.0 s when tuning fork is uncovered - other switching times on request |
|
| 操作条件： | ||
| Installation conditions | ||
| Installation position | see section mounting position | |
| Ambient conditions | ||
| Ambient temperature | -40 ... 70 °C (-40 ... 158 °F) | |
| Storage temperature | -40 ... 85 °C (-40 ... 185 °F) | |
| Shock resistance | a = 300 m/s2 = 30 g, 3 planes x 2 directions x 3 shocks x 18 ms, as per test Ea | |
| Vibration resistance | a(RMS) = 50 m/s2, ASD = 1.25 (m/s2)2/Hz, f = 5 to 2000 Hz, t = 3 x 2 h | |
| Process conditions | ||
| Medium temperature |
-40 ... +100 °C (-40 ... +212 °F) -40 ... +150 °C (-40 ... +302 °F) |
|
| Process pressure (static pressure) | -1 ... +40 bar (-14.5 ... +580 psi) | |
| State of aggregation | liquid | |
| Density | min. 0.7 g/cm3, optional> 0.5 g/cm3 | |
| Viscosity | 1 ... 10000 mPa/s, dynamic viscosity | |
| Solid contents | < ∅5 mm | |
| 机械规格： | ||
| Degree of protection |
- IP65/67, NEMA 4X enclosure (plug M12) - IP65, NEMA 4X enclosure (valve plug) - IP65/68, NEMA 4X/6P enclosure (cable) |
|
| Connection |
- cable 5 m - valve plug NPT1/2 - valve plug QUICKON - valve plug M16 - plug M12 |
|
| Material | see technical information (TI) | |
| Surface quality | Ra < 3.2 µm | |
| Mass | see technical information (TI) | |
| Dimensions | see technical information (TI) | |
| Process connection |
- thread ISO 228 G1/2, G3/4, G1 - thread EN 10226 R1/2, R3/4, R1 - thread ASME MNPT1/2, MNPT3/4, MNPT1 |
|
| 证书和批准： | ||
| Overspill protection |
Z-65.11-554 (overspill protection acc. to WHG) Z-65.40-555 (leak detection system acc. to WHG) If you need the approvals also in paper form, select the option WH in the type code. |
|
| 配件： | ||
| Designation | see technical information (TI) | |
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