共查询到15条相似文献,搜索用时 62 毫秒
1.
2.
3.
4.
5.
6.
讨论了HART(Highway Addressable Remote Transducer)通信协议。选用智能现场设备,设计了HART调制解调器。利用HART通信协议设计了低价格、高精度的管道煤气压力测量方案。 相似文献
7.
8.
9.
10.
11.
传统粉尘仪的维护管理与故障排除效率较低,给生产带来了一定的影响。为改善这一现状,文中提出了采用HART协议作为粉尘仪与上位机的通讯协议,通过对现有的粉尘浓度变送器加以改进,实现HART协议通讯功能。实验证明,改进后的粉尘仪在维护管理和故障诊断方面的效率均有所提高。 相似文献
12.
现场总线已经成为过程控制领域的热点.代表着智能仪表发展的方向。本文着重介绍了纂于HART协议的USB转换器的原理及设计,介绍了硬件电路的原理与实现,同时从软件上实现了与PC的通信.很好地实现了在PC平台下对下位机的控制。 相似文献
13.
在火力发电厂中,使用化学分析仪表检测多通道给水中钠离子、硅酸根和磷酸根的浓度,对减少热力设备的结垢和腐蚀具有重要意义。装置在高性能STM32F103处理器的环境下,采用AD5700调制解调器和AD5421数模转换器的HART通信单元,设计了一套基于HART协议的智能多路给水自动切换装置并进行软硬件开发,有效地解决了在单通道仪表上自动监测6通道给水的问题,具有状态显示、历史曲线、HART数据通讯等功能。 相似文献
14.
首先介绍了HART通信协议及他的优点,然后介绍了HART通信协议在汽油机测速方面的软件实现。该软件主要采用目前流行的VB编程语言。可设计出界面友好、功能强大的测量和监控软件。 相似文献
15.
《Organic Electronics》2014,15(1):1-8
Successful organic photovoltaic (OPV) device fabrication is contingent on selecting an effective encapsulation barrier layer to preserve device functionality by inhibiting atmosphere-induced degradation. In this work, ultra-thin AlOx layers are deposited by atomic layer deposition (ALD) to encapsulate pre-fabricated OPV devices. A summary of ALD recipe effects (temperature, cycling time, and number of cycles) on AlOx film growth and device longevity is presented. First, AlOx film growth on the hydrophobic OPV surface is shown to occur by a 3D island growth mechanism with distinct nucleation and cluster growth regions before coalescence of a complete encapsulation layer with a thickness ⩾7 nm by 500 cycles. Encapsulated device performance testing further demonstrates that reducing ALD processing temperature to 100 °C minimizes OPV phase segregation and surface oxidation loss mechanisms as evidenced by improved short circuit current and fill factor retention when compared with the conventional 140–150 °C range. Ultra-thin AlOx encapsulation by ALD provides significant device lifetime enhancement (∼30% device efficiency after 2000 h of air exposure), which is well beyond other ALD-based encapsulation works reported in the literature. Furthermore, the interfacial bonding strength at the OPV–AlOx interface is shown to play a crucial role in determining film failure mode and therefore, directly impacts ultimate device lifetime. 相似文献