JJG 971-2002 液位计

中华人民共和国国家计量检定规程

JJG971-2002

液位计

LiquidLevelMeasuringDevices

2002一09一13发布2002一12一13实施

国家质量监督检验检疫总局发布

.T.TG971-2002

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本规程经国家质量监督检验检疫总局于2002年09月13日批准，并自

2002年12月13日起施行。

归口单位:全国压力计量技术委员会

主要起草单位:上海市计量测试技术研究院

本规程委托全国压力计量技术委员会负责解释

LIG971-2002

本规程主要起草人:

朱家良(上海市计量测试技术研究院)

屠立猛(上海市计量测试技术研究院)

JJG971-2002

目录

1范围················································································，········……(1)

2引用文献····················································································……(1)

3术语和定义·············································，···································……(1)

3.1设定点误差·············································································……(1)

3.2切换值·······································…·…:····································……(1)

3.3切换差···················································································……(1)

4概述·······················································································……(1)

5计量性能要求········································。···································……(2)

5.1示值误差·(2)

5.2回差·······················································································……(2)

5.3稳定性····················································································……(2)

5.4液位信号输出误差···································································……(2)

5.5设定点误差·············································································……(3)

5.6切换差····················································································……(3)

6通用技术要求············································································……(3)

6.1外观······················································································……(3)

6.2主电源变化影响········································································……(3)

6.3环境温度影响···········································································……(3)

6.4共模干扰影响·····································································，····……(3)

6.5工频磁场抗扰度性能··································································……(3)

6.6静电放电抗扰度性能······························································……(3)

6.7射频电磁场辐射抗扰度性能·························································……(3)

6.8电快速瞬变脉冲群抗扰度性能······················································……(4)

6.9电压暂降、短时中断抗扰度性能···················································……(4)

6.10耐压及密封性········································································……(4)

6.11绝缘电阻·············································································……(4)

6.12绝缘强度·············································································……(4)

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JJC971-2002

6.13运输贮存适应性·················································……·‘……’““’‘““’(4)

6.14防爆性能························、·········，··································一·‘··，……(5)

7计量器具控制···，··················································，·……“·‘……”‘…“““(5)

7.1定型鉴定或样机试验··································，·…·”‘”’‘’‘’‘”‘”’“’“””’“’‘

(5)

7.2首次检定、后续检定和使用中检验········································，·······……(5)

7.3检定结果的处理········，······‘·，··············‘，·····…·…”.‘’‘二‘””““”””’’‘(10)

7.4检定周期·················································································……(10)

附录A定型鉴定或样机试验项目及试验方法········，··············，··】。··-，·……(11)

附录B液位计检定记录格式(14)

附录C检定证书内页格式，··，····，，，·…·’”‘”““”‘’‘“““”’”‘““’’‘“““’”‘’““(17)

JJG971-2002

液位计检定规程

1范围

本规程适用于液位计的定型鉴定、样机试验、首次检定、后续检定和使用中检验。

液位计包括的类型有浮子式、浮球式、浮筒式、压力式、电容式、电导式和反射式

等。用其他原理制造的液位计、物位计也可参照本规程进行检定。

2弓!用文献

本规程引用下列文献:

JJF1001-1998通《用计量术语及定义》

JJF1015-2002计《量器具型式评价和型式批准通用规范》

JJF1016-2002《计量器具型式评价大纲编写导则》

JJG617-1996数《字温度指示调节仪检定规程》

JJG882-1994《压力变送器检定规程》

GB/T17626.2-1998《静电放电抗扰度试验》

GB/T17626.3-1998射《频电磁场辐射抗扰度试验》

GB/T17626.4-1998《电快速瞬变脉冲群抗扰度试验》

GB/T17626.8-1998工《频磁场抗扰度试验》

GB/T17626.11-1999《电压暂降、短时中断和电压变化的抗扰度试验》

JB/T9329-1999《仪器仪表运输、运输贮存基本环境条件及试验方法》

使用本规程时应注意使用上述引用文献的现行有效版本。

术语和定义

3.1设定点误差、etpointerror

输出变量按规定的要求输出时，测得的实际液位与液位设定值之差。

3.2切换值switchingvalue

位式控制仪表上行程(或下行程)中，输出从一种状态变换到另一种状态时所测得

的输入(液位)值。

3.3切换差differentialgap

同一设定点上、下行程切换值之差。

概述

液位计是工业过程测量和控制系统中用以指示和控制液位的仪表。

液位计按功能可分为基地式(现场指示)和远传式(远传显示、控制)两大类。远

传式液位计，通常将现场的液位状况转换成电信号传递到需要监控的场所，或用液位变

1

.IJG971-2002

送器配以显示仪表达到远传显示的目的;液位的控制通常用位式控制方式来实现。

液位计通常由传感器、转换器和指示器三部分组成。具有控制作用的液位计，还有

设定机构。

液位计的工作原理按检测方式不同可以归纳为以下几类:

a)浮力液位测量原理。在液位测量范围内通过检测施加在恒定截面垂直位移元件

上的浮力来测量液位(如浮筒式、浮球式);

b)浮子液位测量原理。通过检测浮子的位置来测量液位，浮子的位置可以用机械、

磁性、光学、超声、辐射等方法检测(如磁翻柱浮球式);

c)浮标和缆索式液位测量原理。根据浮标的位置直接测量液位，浮标的位置由缆

索和滑轮或齿轮凸轮组以机械的方式传送到指示仪和(或)变送器(如浮子式);

d)压力液位测量原理。通过检测液面上、下两点之间的压力差来测量液体的液位

(如压力式);