自营KJ3243X1-BA1日常维护事项范围优势

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KJ3243X1-BA1日常维护事项范围优势一：触摸屏的参数。查看一下触摸屏的参数设置这里面有几个参数需要特别注意的：
1：通信口的设置－－－一定要确认清楚PLC连接触摸屏的COM1口还是COM2口
2：设备类型－－－这个是0重要的，如果协议没选对的话，其他就不用说了
3：连接方式－－－PLC跟触摸屏的连线，确认好事RS485，还是RS232C
4：接口参数跟PLC站号－－－一定要跟PLC里面的设置一致。

二：如果参数确认设置好了，接下来就排查线路的问题确认RS485,RS232C的做线是否正确，触摸屏与各种PLC接线的做法不一样。这个可以参照维控(plc触摸屏通信线接法帮助文档）查看，这个是正常排查通信问题的基本方法。
接下来教大家如何绕开触摸屏的问题－－－在线模拟。在通讯不上的时候，有的客户会猜测可能是触摸屏的问题，或者接口的问题。在线模拟就是绕开触摸屏，直接用PLC跟电脑进行连接。



具体的做法：

1：PLC跟电脑要通过RS232进行连接。有的PLC有RS232的接口，有的没有，没有的可以通过转接头接到电脑上。

2：新建一个简单的工程。放两个元器件，一个数值显示，一个数值输入。地址设置PLC里面的地址。

3：工程参数设置一定要跟PLC里面的设置一样。

4：点击在线模拟功能

这样子做就可以很明显查看PLC能不能跟PC通信上。如果可以通信上就可以排除PLC方面的问题，跟参数设置的问题。

在短短数十年间，计算机科学与技术取得了突破性的进展，并且广泛应用于多个行业之中，同时，在行业发展过程中，也将计算机科学与技术的应用效果与质量作为一项重要衡量指标。在教育领域中，计算机科学与技术作为一种有效的教学资源，有助于提高教学质量以及教学管理效率。在课堂教学中应用计算机科学与技术，有助于提高学生的学习积极性，为培养“互联网+”时代下的新型人才打好基础。在社会的发展过程中，计算机科学技术的发展具有十分显著的影响力，科学技术是社会发展的0一生产力，对提升人们的生活水平具有十分显著的应用价值。处于信息技术高速发展的时代中，各行各业都对计算机科学与技术进行了合理运用，尤其是教育领域计算机科学与技术的应用具有十分显著的效果，但就现阶段的初中教学工作而言，教师未能合理利用计算机科学与技术展开教学工作。

一、初中计算机科学与技术现代化应用中存在的问题

（一）缺乏计算机科学与技术的现代化应用意识在信息化技术快速发展的背景下，人们的生活与计算机科学与技术之间存在密不可分的联系，将计算机技术应用在初中教学工作中是未来发展的必然趋势。但就目前的初中教学实际情况而言，学校对计算机科学技术的现代化运用缺乏重视，计算机一周只设置一节课程，而计算机是具有较强应用性的学科，学校的课程设置无法满足学生进行实践操作的学习需求，导致学生对计算机科学与技术的学习依然局限于理论知识。其次，大部分家长更重视学生的学习成绩，忽视了学生学习计算机科学与技术的重要性[1]。

（二）计算机科学与技术在教学与管理中缺乏普遍性

在初中教学过程中，现代化教学与管理必须以计算机为依托，但在实际教学中，大部分初中教师依然使用传统教学模式，无法在教学过程中合理应用计算机资源与教学手段，导致课堂教学内容枯燥、乏味，学生不能积极主动地投入课堂学习中，并且在教学管理中也未能妥善应用计算机科学与技术。

二、初中计算机科学与技术的现代化应用策略

（一）建立现代化教学管理体系

通过利用计算机科学与技术建立教学管理体系，从而提高学校对学生的管理效率。例如，学校可以利用计算机技术建立学生档案，包括学生的个人基本信息、兴趣爱好等，这对教师在教学工作中实施针对性教学具有重要意义，同时有助于提升学生管理工作的质量。其次，还可以通过利用计算机技术建立课程评价体系，学生在学习结束后可以利用网络对教师的课堂教学工作做出点评，从而有助于学校更合理地设置课程。0后，提高管理教师队伍质量[2]。教师在实际教学过程中可以通过利用计算机科学与技术开会，减少了不必要的时间浪费，有助于提高教师绩效考核的准确度。

（二）提升现代化教学模式质量

首先，通过在初中教学工作中应用计算机科学与技术，能够转变传统教学模式，提高现代化教学的质量。初中教学过程中，在传统的教学模式下，有限的教学时间无法确保学生对知识难点、重点进行更好的把握，而通过计算机科学技术展开教学，学生在学习新知识之前可以做好课前预习工作，同时，教师也可以明确学生的知识预习掌握情况，有助于在课堂教学中为学生实施针对性教学，从而提高学生成绩。其次，教师教学过程中利用计算机科学与技术，将各个学科枯燥乏味的理论知识转变为生动的情境，使知识能够在学生脑海中形成画面，提高学生对知识的学习兴趣。0后，在教学中利用计算机科学与技术，能够提高学生的自主学习能力，有助于学生形成独立思考的思维模式[3]。

三、结语

在初中教学中，应用计算机科学与技术是时代发展的必然需求。在课堂教学中，通过计算机科学与技术的现代化应用，促使学生积极分享生活中的学科知识，为学生提供交流讨论的平台，对培养学生的创新思维以及自主学习能力有一定的积极意义，有助于提高教学效率。GE 发电机管理继电器的部件号 489-P5-HI-A20-E 中的 E 代表什么？ 部件号 489-P5-HI-A20-E GE 发电机管理继电器中的 E 代表增强型显示器，其 LCD 比基本显示器更大。
如何更改值的范围？ 按下帮助按钮，它将显示有关设定点的敏感内容。值的范围以及如何更改设定值在帮助消息中。
489-P5-HI-A20-E GE发电机管理继电器如何显示发电量？ 在部件号为 489-P5-HI-A20-E 的发电机管理继电器上，产生的功率为正瓦特。按照惯例，感应发电机通常需要无功功率，形成励磁系统。
489 发电机管理继电器有什么作用？ 489 GE 发电机管理继电器管理发电机的同步和感应，它是一种基于微处理器的继电器，旨在保护和管理发电机。
基于微处理器或固态继电器通常用于提供多种设置和曲线选项。
介电耐压是参考标准 EN60255-5。
耐冲击电压是参考标准 EN60255-5。
绝缘电阻为参考标准 EN60255-5。
阻尼振荡是参考标准 IEC61000-4-18/IEC60255-22-1。
静电放电是参考标准 EN61000-4-2/IEC60255-22-2。
RF 抗扰度是参考标准 EN61000-4-3/IEC60255-22-3。
快速瞬态干扰是参考标准 EN61000-4-4/IEC60255-22-4。
浪涌抗扰度是参考标准 EN61000-4-5/IEC60255-22-5。
传导射频抗扰度是参考标准 EN61000-4-6/IEC60255-22-6。
辐射和传导发射是参考标准 CISPR11/CISPR22/IEC60255-25。
正弦振动是参考标准 IEC60255-21-1。
电源磁抗扰度为参考标准 IEC61000-4-8。
电压骤降​​和中断是参考标准 IEC61000-4-11。
入口保护是参考标准 IEC60529。
环保（冷）是参考标准IEC60068-2-1。
环保（干热）参考标准IEC60068-2-2。
相对湿度循环是参考标准 IEC60068-2-30。
EFT 是参考标准 IEEE/ANSI C37.90.1。
阻尼振荡是参考标准 IEEE/ANSI C37.90.1。
ESD 是参考标准 IEEE/ANSIC37.90.3。
安全性是参考标准 UL508、UL C22.2-14 和 UL1053。
相对湿度循环是参考标准 IEC60068-2-30。
EFT 是参考标准 IEEE/ANSI C37.90.1。
阻尼振荡是参考标准 IEEE/ANSI C37.90.1。
ESD 是参考标准 IEEE/ANSIC37.90.3。
安全性是参考标准 UL508、UL C22.2-14 和 UL1053。
相对湿度循环是参考标准 IEC60068-2-30。
EFT 是参考标准 IEEE/ANSI C37.90.1。
阻尼振荡是参考标准 IEEE/ANSI C37.90.1。
ESD 是参考标准 IEEE/ANSIC37.90.3。
安全性是参考标准 UL508、UL C22.2-14 和 UL1053。一、事例
有一个客服工单体系，会从邮件服务器中获取客服邮箱收到的邮件，而且将这些邮件主动生成工单并主动分配给相应的客服组，每次客服人员从工单列表中选取一个工单进行处理，每处理一次就会发生一个工单处理记载，直到工单被客服封闭间断。
该体系现已运行了一年，在这一年中一共发生了一千万个工单和五千万条工单处理记载。因为全部工单和处理记载都存储在一个数据库中，因而每次客服查看工单列表时会很慢，可是客服还能忍耐。直到某天，公司选择将其他几种类型的客服邮件也都参加到客服工单体系中，就呈现了很大的问题，工单数量急剧增加，导致工单列表翻开速度越来越慢，乃至构成客服工单体系溃散。
开发人员收到反应后，剖析如下：

工单数量每天的增加量是本来的3倍；
工单总量现已超越3000万；
工单处理记载现已过亿。
依据上面的剖析，不难看出是因为数据量过大构成的，所以开发人员进行了0常见的操作：优化库结构、优化体系代码、加索引等操作。虽然体系不再呈现溃散的状况，可是工单列表的查询依然很慢。经过开发组内部评论，拟定了如下两个计划：

数据库分区
数据冷热别离
下面咱们就来具体看一下这两种计划的思路和优缺点。

二、数据库分区
2.1 什么是分区
分区，并不是呈现新的数据表，而是在不创立新表的状况下，将表中的数据依照必定规矩分配存储到不同的位置（硬盘、体系乃至是服务器中）。

Tip：因为本专题阐明的是架构常识，因而在大部分状况下不会涉及到某项技能、某种言语的阐明。

数据库分区有如下四个利益：

分区能够存储更多的数据，因为表中数据都被存储在的不同的硬盘、体系或服务器中；
跟着数据的增加，能够随时增加新的分区来存储数据；
在整理数据的时分，能够直接删去分区；
优化了查询速度，每次查询数据时咱们不需求查询全部数据，只需求查询特定分区即可，例如数据表依照日期分区，每个年月是一个分区，那么当咱们查询某年某月的数据时，只需求一个分区的数据即可（当然，这儿说的查询或许不谨慎，这儿仅仅举例子算了，不用介怀，关于查询的处理我将在后边的文章中介绍）。
那么该怎样分区呢？下面咱们就以客服工单体系为例来阐明一下。

2.2 针对客服工单体系的处理计划
在客服工单体系中，咱们有一个工单表，首要的表结构由：工单编号、工单创立日期、工单状况（进行中、无人处理、已封闭）、客服究竟操作时刻、究竟处理人以及究竟处理人地点组组成。针对工单表的查询操作如下：

客服查询无人处理的工单；
客服查询自己接手的工单；
客服组长查询本组的工单；
客服查询某个客户的工单；
客服主管/组长查询0近一个月完毕的工单。
为了结束在查询时只查询特定的分区，咱们需求在查询条件中包含分区字段，可是就现在而言这四个查询操作并没有共有的字段。那么，咱们就来创立这个分区字段，首要咱们来剖析一下哪些字段适合作为分区字段。

体系在邮件服务中获取到客服邮件后会创立工单；
客服需求查询无人处理的工单；
客服查询自己正在处理的工单；
客服主管/组长查询0近一个月工单完毕的状况；
工单处理完毕后，客服封闭工单。
剖析的这五个方面，呈现了三个适合做分区的字段：工单创立时刻、工单状况、客服究竟操作时刻。那么哪个或哪几个更适合做分区字段呢？依据上面的剖析可知咱们能够将工单状况和客服究竟操作时刻作为分区的字段，进行中、无人处理以及0近一个月内封闭的工单放在一个A分区中，超越一个月的已封闭的工单放在一个B分区中。经过这样的处理，工单列表的查询速度就有了质的前进，每次查询 SQL 语句只用去扫描A分区就能够了。
可是，假定要这样做的话要考虑如下几个点：

开发组是否具有数据库分库经历；
因为要在出产环境中分区，因而要考虑分区给出产环境带来的影响。
三、数据冷热别离
在学习数据冷热别离前咱们先来看一下底子概念

3.1 底子概念
冷热数据：
所谓的冷数据指的是不常用的，状况底子不变的数据，热数据指的是常常运用，而且会对其进行操作的数据。
冷热库：
存放冷数据的数据库被称为冷库，存放热数据的数据库被称为热库。
冷热别离：
在处理数据时，将数据依照冷热分为冷库和热库，在咱们的事例中工单表是热库。
3.2 冷热别离计划
冷热别离计划有两种，一种是冷热数据都运用同一种类型的数据库，另一种是将冷数据存储在NoSQL数据库中。下面们我来别离阐明一下。

3.2.1 计划一：同类型数库存储
一般来说这个计划能够处理大部分数据存储问题，而且冷热库运用的是相同的库结构，数据从热库搬迁到冷库时不用进行数据转化，而且代码部分改动较小。和数据库分区相同，咱们在实施这个计划前，需求考虑这几个问题：

怎样判别数据冷热；
冷热数据别离怎样触发；
冷热数据别离怎样结束；
冷热数据怎样运用。
下面就针对这4个方面进行阐明

3.2.1.1 怎样判别数据冷热
常见的判别办法是，依据主表中的一个或几个字段来判别。比方在工单体系中，能够运用工单状况、客服究竟操作时刻来作为冷热数据的判别条件，将现已封闭的而且超越一个月的工单视为冷数据，其他的工单视为热数据。
在判别冷热数据中，咱们应遵循以下原则：

数据一旦被搬迁到冷库中，就代表事务代码只能对它进行查询操作；
冷热数据不能一起读取。
3.2.1.2 冷热数据别离怎样触发
触发冷热数据别离的办法有三种：在批改操作的代码后边加上触发冷热别离的代码、监听数据库改动日志、守时扫描数据库。针对这三种办法来一一阐明。

在批改操作的代码后边加上触发冷热别离的代码
在每次批改了数据后，都会触发实施冷热别离的代码。这种办法比较简单，每次只需求判别以下是否变成了冷数据即可，虽然能确保数据实时性，可是无法依照日期时刻来差异冷热数据，而且全部与数据批改相关的代码都要加上冷热别离代码。因而这种办法运用的较少，一般用在小型体系上。
监听数据库改动日志
这种办法需求创立一个新服务来监听数据库改动日志，一旦发现相关的表发生了变动就触发冷热别离逻辑。这种办法又分为两种子办法，一个是直接触发冷热别离逻辑，另一个是将表更的数据发送到部队里（能够是自定义的公共 List，也能够是MQ），订阅放从部队中获取到数据后实施冷热别离逻辑。这种办法的利益是与事务代码完全解耦，低推延，可是缺点和办法一相同无法依照日期来差异冷热数据，而且会呈现事务代码和冷热别离逻辑代码一起操作同一条数据的问题，也就是并发问题。
守时扫描数据库
这种办法也是新建一个服务，守时扫描数据库。一般咱们会运用使命调度渠道来结束，或许经过0三方开源的库/组件来结束，当然，假定你乐意也能够经过编写操作体系守时使命来结束。这种办法的利益是与事务代码别离，而且能够依据日期时刻差异冷热数据，缺点是无法做到实时性。
依据上面三种办法的描绘来看，工单体系适合运用守时扫描数据库的办法来结束冷热别离。

3.2.1.3 冷热数据别离怎样结束
现已有了冷热数据别离的处理计划了，那么在这一末节里咱们来看看怎样结束冷热别离。
结束冷热别离的底子进程如下：

判别数据冷热；
将冷数据刺进冷库；
将冷数据从热库中删去。
要结束这三个底子进程，咱们需求考虑以下内容：
在前面三个进程中，咱们无法百分百确实保不会出问题，因而咱们有必要经过代码来确保数据的究竟一致性。要结束究竟一致性，咱们能够在工单表中新加一个列 是否冷数据（是、否，默许：否）。首要冷热数据别离服务将找到的冷数据全都标记为是冷数据，接着服务将冷数据搬迁到冷库中，搬迁结束后就从热库中将对应的数据删掉。假定在搬迁或许删去数据的时分呈现了反常，那么咱们就需求在搬迁和删去数据的事务代码中参加重试机制（这儿一般会用干流的重试库，比方.NET中的Polly，Java中的guava-retry等）。假定屡次重试后依然不成功，那么代码能够间断冷热数据别离的实施并发出警告，或许越过不成功的数据，继续实施后续数据的搬迁。在删去不成功而且越过的状况下，很有或许会呈现在下次实施冷热数据别离的时分在冷库中刺进重复数据的状况，那么咱们就需求在刺进前判别冷库中是否存在该条数据，也能够运用数据库的幂等操作来结束刺进操作（比方MySQL数据库的 Insert …On Duplicate Key Update 语句）。
到这儿，咱们考虑一个问题，工单体系数据量巨大，假定一次性将全部冷数据刺进到冷库中的话是很慢的，有或许需求几十分钟乃至几个小时，那么处理这个问题的绑法有两种：一种是批处理，一种是多线程处理。

Tip：何为幂等？完全相同的恳求/操作，屡次实施的成果和实施一次的成果相同。

咱们先来说说批处理的办法。例如咱们的工单体系中的标明的冷数据有1000万条，那么咱们能够依照如下的进程进行处理冷热别离：

取出前1万条冷数据；
将这1万条冷数据存储到冷库中；
从热库中删去这1万条冷数据；
循环1到3，直至说有冷数据搬迁结束。
咱们再来说说对线程处理的办法。多线程处理的办法分两种，一种是设置多个不同的守时器，每个守时器会在估计的距离时刻里发起一个线程来处理数据。另一种是运用线程池，先计算出需求搬迁的冷数据总数，再依据每个线程0大搬迁数据量计算出需求多少个线程，假定所需线程数量超越线程池中线程的数量的话，那么就将线程池中的全部线程全部发起（并不是线程越多功率越高）。这两种办法的底子原理都相同，同样需求留心的问题也是相同的。
数据搬迁时应该怎样避免多个线程搬迁同一条冷数据呢？咱们能够运用锁。在工单表上增加一个 加锁线程ID 字段，用来标识当时数据正在被线程处理。线程每次在获取数据后，就需求对自己所获得的数据的加锁线程ID字段写入自己的线程ID。写入线程ID后并不能直接开始搬迁数据了，而是在搬迁数据前再查询一次自己承认的数据，这是避免向加锁线程ID字段加写入数据前被其他线程提早写入了数据，然后导致多个线程处理同一条数据的问题。再次查询后咱们就能够进行数据搬迁了，可是要留心数据搬迁所用的数据是再次查询后获得数据，而不是线程刚开始获得的数据。
到这儿，又有一个问题，假定某个线程挂掉了，锁就有很大或许没有释放（位于工单表中的冷数据没被删去），该怎样处理？其实很简单，在工单表中增加锁守时刻列来记载被承认的时刻，并设置当锁守时刻超越N分钟后（例如5分钟，N的值需求在查验环境中进行屡次查验后取平均值）就能够被其他线程从头承认。
当然这又呈现另一个问题，假定某个线程没有挂，可是处理数据的时刻也确实超时了，其他线程只知道数据承认超时了，该怎样办？咱们能够运用上一末节所说的数据库的幂等操作来结束刺进操作。

3.2.1.4 冷热数据怎样运用
这个问题处理起来也很简单，咱们能够将冷数据查询和热数据查询分红两种操作，默许只能查询热数据，当需求查询冷数据时向服务端传递一个标识来奉告需求查询冷数据。

TIP：必定不要进行冷热数据的一起查询： Touch screen parameters. Check the parameter settings of the touch screen



There are several parameters that need special attention:



1: The setting of communication port -- be sure to confirm whether the COM1 port or com2 port connecting the PLC to the touch screen



2: Device type - - this is the most important. If the protocol is not selected correctly, it goes without saying anything else



3: Connection mode - the connection between PLC and touch screen, confirm whether it is RS485 or RS232C



4: Interface parameters and PLC station number must be consistent with the settings in PLC.





2： If the parameters are confirmed and set, then check the line



Confirm whether the wiring of RS485 and RS232C is correct, and the wiring method of touch screen is different from that of various PLC. This can be checked by referring to the maintenance control (help document of communication line connection between PLC and touch screen). This is the basic method for normal troubleshooting of communication problems.





Next, I will teach you how to bypass the problem of touch screen - online simulation. When communication is not available, some customers will guess that it may be the problem of the touch screen or the interface. Online simulation is to bypass the touch screen and connect directly with the computer with PLC.





Specific measures:



1: PLC and computer shall be connected through RS232. Some PLCs have RS232 interfaces, some do not, and others can be connected to the computer through the adapter.



2: Create a new simple project. Put two components, one value display and one value input. Address set the address in PLC.



3: The engineering parameter setting must be the same as that in PLC.



4: Click online simulation function



In this way, it is obvious to check whether PLC can communicate with PC. If you can communicate, you can eliminate the problems of PLC and parameter setting.



In just a few decades, computer science and technology have made breakthroughs, and are widely used in many industries. At the same time, in the process of industry development, the application effect and quality of computer science and technology are also regarded as an important measurement index. In the field of education, computer science and technology, as an effective teaching resource, help to improve the quality of teaching and the efficiency of teaching management. The application of computer science and technology in classroom teaching helps to improve students' learning enthusiasm and lay a good foundation for cultivating new talents in the era of "Internet +". In the process of social development, the development of computer science and technology has a very significant influence. Science and technology is the primary productive force of social development, and has a very significant application value to improve people's living standards. In the era of rapid development of information technology, all walks of life have made rational use of computer science and technology, especially in the field of education. The application of computer science and technology has a very significant effect. However, as far as junior middle school teaching is concerned at this stage, teachers have failed to make reasonable use of computer science and technology to carry out teaching work.



1、 Problems in the application of computer science and technology modernization in junior middle school



（1） Lack of modern application awareness of computer science and technology in the context of the rapid development of information technology, there is an inseparable link between people's life and computer science and technology. The application of computer technology in junior high school teaching is an inevitable trend of future development. However, in terms of the actual situation of junior middle school teaching at present, the school lacks attention to the modern application of computer science and technology. Computers are only set up one course a week, and computers are a subject with strong applicability. The curriculum setting of the school cannot meet the learning needs of students for practical operation, resulting in students' learning of computer science and technology is still limited to theoretical knowledge. Secondly, most parents pay more attention to students' academic performance, ignoring the importance of students' learning computer science and technology [1].



（2） Computer science and technology lack universality in teaching and management



In the process of junior middle school teaching, modern teaching and management must rely on computers, but in actual teaching, most junior middle school teachers still use the traditional teaching mode, unable to reasonably apply computer resources and teaching methods in the teaching process, resulting in dry and boring classroom teaching content, students can not actively participate in classroom learning, and computer science and technology can not be properly applied in teaching management.



2、 Modern application strategy of computer science and technology in junior middle school



（1） Establish a modern teaching management system



Through the use of computer science and technology to establish a teaching management system, so as to improve the efficiency of school management of students. For example, schools can use computer technology to establish student files, including students' basic personal information, interests and hobbies, which is of great significance for teachers to implement targeted teaching in teaching work, and help to improve the quality of student management. Secondly, by using computer technology to establish a curriculum evaluation system, students can use the network to comment on Teachers' classroom teaching work after learning, which helps schools set up courses more reasonably. Finally, improve the quality of management teachers [2]. In the actual teaching process, teachers can use computer science and technology to hold meetings, which reduces unnecessary waste of time and helps to improve the accuracy of teacher performance appraisal.



（2） Improve the quality of modern teaching mode



First of all, through the application of computer science and technology in junior high school teaching, we can change the traditional teaching mode and improve the quality of modern teaching. In the teaching process of junior middle school, under the traditional teaching mode, the limited teaching time can not ensure that students have a better grasp of the difficulties and key points of knowledge. Through the teaching of computer science and technology, students can do a good job of pre class preview before learning new knowledge. At the same time, teachers can also clarify the students' knowledge preview and grasp, which is conducive to the implementation of targeted teaching for students in classroom teaching, So as to improve students' grades. Secondly, teachers use computer science and technology in the teaching process to turn the boring theoretical knowledge of various disciplines into vivid situations, so that knowledge can form a picture in students' minds and improve students' interest in learning knowledge. Finally, the use of computer science and technology in teaching can improve students' autonomous learning ability and help students form a thinking mode of independent thinking [3].



3、 Conclusion



In junior middle school teaching, the application of computer science and technology is the inevitable demand of the development of the times. In classroom teaching, through the modern application of computer science and technology, students are encouraged to actively share subject knowledge in life and provide a platform for students to exchange and discuss, which is of certain positive significance to cultivate students' innovative thinking and autonomous learning ability, and is conducive to improving teaching efficiency. What does e stand for in part number 489-p5-hi-a20-e of Ge generator management relay? Part number 489-p5-hi-a20-e e e in Ge generator management relay stands for enhanced display, whose LCD is larger than the basic display.

How to change the range of values? Press the help button, which will display sensitive content about the setpoint. The range of values and how to change the set value are in the help message.

489-p5-hi-a20-e how does the Ge generator management relay display power generation? On the generator management relay with part number 489-p5-hi-a20-e, the power generated is positive watts. By convention, induction generators usually require reactive power to form an excitation system.

489 what is the function of generator management relay? 489 Ge generator management relay manages the synchronization and induction of generators. It is a microprocessor-based relay designed to protect and manage generators.

Microprocessor based or solid state relays are often used to provide a variety of settings and curve options.

Dielectric withstand voltage refers to en60255-5.

Impulse voltage resistance refers to en60255-5.

The insulation resistance is the reference standard en60255-5.

Damping oscillation refers to iec61000-4-18 / iec60255-22-1.

Electrostatic discharge refers to the standard en61000-4-2/iec60255-22-2.

RF immunity refers to the standard en61000-4-3/iec60255-22-3.

Fast transient interference refers to the standard en61000-4-4 / iec60255-22-4.

Surge immunity refers to the standard en61000-4-5/iec60255-22-5.

Conducted RF immunity refers to the standard en61000-4-6 / iec60255-22-6.

Radiation and conducted emissions refer to the standard cispr11/cispr22/iec60255-25.

Sinusoidal vibration refers to iec60255-21-1.

The magnetic immunity of power supply is the reference standard iec61000-4-8.

Voltage dips and interruptions refer to iec61000-4-11.

Entrance protection refers to IEC60529.

Environmental protection (cold) is the reference standard iec60068-2-1.

Environmental protection (dry heat) refers to iec60068-2-2.

The relative humidity cycle is the reference standard iec60068-2-30.

EFT is the reference standard ieee/ansi c37.90.1.

Damped oscillation is the reference standard ieee/ansi c37.90.1.

ESD is the reference standard ieee/ansic37.90.3.

Safety refers to standards ul508, UL c22.2-14 and ul1053.

The relative humidity cycle is the reference standard iec60068-2-30.

EFT is the reference standard ieee/ansi c37.90.1.

Damped oscillation is the reference standard ieee/ansi c37.90.1.

ESD is the reference standard ieee/ansic37.90.3.

Safety refers to standards ul508, UL c22.2-14 and ul1053.

The relative humidity cycle is the reference standard iec60068-2-30.

EFT is the reference standard ieee/ansi c37.90.1.

Damped oscillation is the reference standard ieee/ansi c37.90.1.

ESD is the reference standard ieee/ansic37.90.3.

Safety refers to standards ul508, UL c22.2-14 and ul1053. 1、 Examples

There is a customer service work order system, which will obtain the emails received from the customer service mailbox from the mail server, and actively generate work orders from these emails and actively allocate them to the corresponding customer service group. Each time the customer service staff selects a work order from the work order list for processing, a work order processing record will occur each time, until the work order is closed and interrupted by customer service.

The system has been running for one year, during which a total of 10 million work orders and 50 million work order processing records have occurred. Because all work orders and processing records are stored in one database, customer service will be slow every time when viewing the work order list, but customer service can tolerate it. Until one day, the company chose to include other types of customer service emails in the customer service work order system, which presented a big problem. The number of work orders increased sharply, resulting in the slower and slower opening of the work order list, and even the collapse of the customer service work order system.

After receiving the response, the developer analyzed it as follows:



The daily increase in the number of work orders is 3 times that of the original;

The total number of work orders has exceeded 30million;

The record of work order processing has exceeded 100 million.

According to the above analysis, it is not difficult to see that it is caused by the excessive amount of data, so developers have carried out the most common operations: optimizing the library structure, optimizing the system code, adding indexes and so on. Although the system is no longer collapsing, the query of work order list is still very slow. After internal comments of the development team, the following two plans are drawn up:



Database partition

Hot and cold data separation

Now let's take a look at the ideas, advantages and disadvantages of these two plans.



2、 Database partition

2.1 what is zoning

Partitioning is not to present a new data table, but to allocate and store the data in the table to different locations (hard disk, system and even server) according to certain rules without creating a new table.



Tip: because this topic clarifies the common sense of architecture, it will not involve the clarification of a certain skill or a certain language in most cases.



Database partitioning has the following four benefits:



Partitions can store more data, because the data in the table are stored in different hard disks, systems or servers;

With the increase of data, new partitions can be added at any time to store data;

When sorting data, the partition can be deleted directly;

The query speed is optimized. Each time we query data, we don't need to query all the data, but only need to query specific partitions. For example, the data table is partitioned according to the date, and each year and month is a partition. Then when we query the data of a certain year and month, You only need the data of one partition (of course, the query here may not be cautious. Here is just an example. Don't worry, I will introduce the query processing in the following article).

So how to partition? Let's take the customer service work order system as an example to illustrate.



2.2 processing plan for customer service work order system

In the customer service work order system, we have a work order table. The primary table structure is composed of: work order number, work order creation date, work order status (in progress, unattended, closed), the actual operation time of customer service, the actual handler, and the actual handler location group. The query operations for the work order table are as follows:



Customer service inquires about the work orders that are not handled;

Customer service inquires about the work order they took over;

The customer service team leader queries the work order of the team;

Customer service queries the work order of a customer;

The customer service supervisor / team leader inquires about the work orders completed in the latest month.

In order to end the query of only a specific partition, we need to include the partition field in the query criteria, but for now, these four query operations do not have a common field. Then, let's create this partition field. First, let's analyze which fields are suitable for partition fields.



The system will create a work order after obtaining the customer service email in the email service;

Customer service needs to query work orders that are not handled;

Customer service queries the work order they are processing;

The customer service supervisor / team leader inquires about the completion of work orders in the latest month;

After the work order is processed, the customer service closes the work order.

The five aspects analyzed present three fields suitable for zoning: the time when the work order was created, the status of the work order, and the actual operation time of customer service. So which or which ones are more suitable for partition fields? According to the above analysis, we can take the work order status and the actual operation time of customer service as the fields of the partition. The work orders that are in progress, unattended and closed within the last month are placed in a partition a, and the closed work orders that have exceeded a month are placed in a partition B. After such processing, the query speed of the work order list has made a qualitative progress. Each time you query the SQL statement, you only need to scan partition a.

However, if you want to do so, you should consider the following points:



Whether the development team has database sub database experience;

Because it needs to be partitioned in the production environment, the impact of zoning on the production environment should be considered.

3、 Hot and cold data separation

Learning numbers

3.2.2 计划二：NoSQL存储
前面讲了同类型数据库冷热存储，运用NoSQL存储的原理是相同的，只不过是把冷库从联络型数据库改为了 NoSQL，进程和留心事项也是相同的。可是运用 NoSQL 存储冷库的利益是数据量不论多大，只要在 NoSQL的接受范围内，查询速度都要比联络型数据库作为冷库要快，因为咱们的冷库数据仍是许多的。现在市面上的大部分盛行 NoSQL 都适合做冷库运用，在实践项目中需求依据开发组技能水平、项目需求和运维本钱等方面来选择运用哪个 NoSQL 作为冷库。