How to calibrate RTD temperature transmitters - Beamex

Summary

本视频由Phoenix BMX和ISA的Michael制作，向观众展示了如何校准RTD温度变送器。首先介绍了两种校准方法，一种是将温度元件连接到变送器并放入加热块中，另一种是通过模拟器模拟电阻变化。视频中详细演示了使用校准器和模拟器进行校准的过程，包括连接测试导线、进行纸面校准、使用通讯器进行传感器调整等步骤。最终，通过精确调整，成功将变送器校准至规格内，并强调了测试设备的准确性和可追溯性的重要性。

Takeaways

• 🔧 校准RTD温度变送器并不困难，有两种主要方法。
• 🌡️ 使用温度元件连接到变送器是常见的校准方法之一。
• 🛁 当无法将探头实际放入温度浴中时，可以通过模拟电阻来校准。
• 📈 通过校准器连接并测量电流，可以观察到4-20mA输出的变化。
• 🔌 四线RTD的连接方式是关键，需要正确连接测试线。
• 📊 使用校准器进行模拟时，可以设置温度范围和校准点。
• 🛠️ 校准过程中可能出现误差，需要通过调整传感器来修正。
• 🔄 进行多点校准时，应确保测试设备准确且可追溯。
• 🔧 使用通讯器进行传感器的精细调整，包括零点和满度调整。
• 📝 校准完成后，应记录校准结果和相关信息。
• 🔄 校准成功后，应断开所有连接并将变送器重新放回系统中。

Q & A

什么是RTD以及它的主要用途是什么？

RTD是电阻温度检测器（Resistance Temperature Detector）的缩写，主要用于测量温度。它通过检测材料的电阻变化来确定温度，常用于精确温度测量的场合。

在视频中提到的四线RTD是什么意思？

四线RTD指的是使用四根导线连接的温度传感器，它可以消除导线电阻对测量结果的影响，从而提供更精确的温度读数。

如何将RTD传感器连接到温度变送器？

将RTD传感器的四根导线分别连接到温度变送器的相应端子上，通常是将两个导线连接到变送器的电源端子，另外两个导线连接到变送器的信号输出端子。

如果不能将RTD传感器实际放入温度校准浴中，有什么替代方案？

如果不能将RTD传感器放入温度校准浴中，可以使用模拟器来模拟传感器的电阻变化，从而进行校准。

在校准RTD传感器时，为什么不能直接读取0到100摄氏度的范围内的4到20mA输出？

因为RTD传感器的电阻变化与温度之间的关系是非线性的，所以不能直接将4到20mA输出与0到100摄氏度的温度范围相对应，需要通过校准来建立这种关系。

在校准过程中，如果发现校准失败，应该怎么办？

如果校准失败，应该检查RTD传感器和温度变送器的连接是否正确，确认使用的校准设备是否准确，并且可能需要重新进行传感器的调整和校准。

如何使用通讯器对RTD传感器进行调整？

使用通讯器连接到RTD传感器，进入诊断和服务菜单，选择传感器调整选项，按照指示进行两点调整（包括低端和高端），并进行模拟校准信号的输入，以调整传感器的输出。

为什么测试设备需要比被测试单位更精确？

测试设备需要比被测试单位更精确，以确保测量结果的准确性。通常测试设备的精确度需要是被测试单位的四倍，这样才能检测出被测试单位的误差。

测试设备需要具备哪些特性？

测试设备需要具备两个关键特性：一是比被测试单位更高的精确度，二是可追溯性，即测试设备需要定期进行校准，以确保其测量结果能够追溯到国家标准。

在校准RTD传感器后，需要做什么来保存校准结果？

在校准完成后，需要在测试设备上保存校准结果，这通常包括校准的日期、执行校准的人员、校准的参数以及任何相关的校准备注。

完成RTD传感器校准后，下一步应该做什么？

完成RTD传感器的校准后，应该断开所有连接线，并将传感器重新安装回过程中，确保传感器可以正常工作并提供准确的温度读数。

Outlines

00:00

🔧 介绍与RTD校准基础

本段落介绍了Michael从Phoenix BMX和ISA，他制作了一个视频来展示如何校准RTD（电阻温度检测器）温度传感器。他解释了校准RTD传感器的基本方法，包括两种选项：一种是将温度元件连接到传感器并将其放入加热块中进行实际校准；另一种是通过模拟器对传感器进行电阻模拟，从而观察4-20mA输出的变化。Michael还展示了如何使用校准器连接传感器，并测量毫安输出，以及如何将4-20mA输出与0-100摄氏度进行比例转换。

05:00

📊 校准过程与故障分析

在这一段中，Michael继续讲解了校准过程，包括使用文档校准器进行无纸化校准。他展示了如何设置校准器，模拟传感器的电阻变化，并进行五个校准点的测试。通过观察校准结果，Michael指出当前的校准失败了，因为误差超过了规定的0.5%的容差范围。他解释了校准失败的原因，并展示了如何使用内置的通讯器对传感器进行调整，以恢复到规格要求。

10:02

🔄 完成校准与测试设备的重要性

最后一段中，Michael完成了对RTD传感器的校准，并强调了测试设备的重要性。他提到测试设备需要比被测试单位更精确，并且需要可追溯到国家标准。通过再次校准，他展示了如何确保传感器的输出在容差范围内，并解释了校准过程中的关键点。最后，他总结了如何使用校准器完成RTD温度传感器的校准，并提醒观众在完成校准后断开所有连接，并将传感器重新放回过程中。

Keywords

💡RTD

RTD是'Resistance Temperature Detector'的缩写，即电阻温度检测器。它是一种温度传感器，通过测量其电阻值的变化来确定温度。在视频中，RTD与温度变送器配合使用，用于精确测量和传输温度数据。

💡温度变送器

温度变送器是一种将温度信号转换为可远距离传输的标准输出信号的设备，如4-20mA电流信号。它通常与RTD或热电偶等温度传感器配合使用。视频中，温度变送器用于接收RTD的温度信号并输出相应的电流信号。

💡校准

校准是指将测量设备或传感器与已知标准进行比较，并调整以确保其测量结果的准确性的过程。在视频中，校准RTD温度变送器是为了确保其输出的温度读数与实际温度相符。

💡4-20mA

4-20mA是一种常用的工业过程控制信号，代表电流范围从4毫安到20毫安。这种信号可以用来传输模拟量，如温度、压力等。在视频中，温度变送器输出4-20mA电流信号，以表示测量到的温度值。

💡模拟

在测量和校准过程中，模拟是指使用特定的设备或方法来复制或重现传感器或变送器的输出，而不需要实际改变被测量的物理量。在视频中，模拟RTD的电阻是为了在校准过程中不需要实际改变温度。

💡电阻

电阻是物质对电流流动的阻碍作用的度量。在RTD中，电阻随温度变化而变化，因此通过测量电阻可以确定温度。视频中学到，通过模拟RTD的电阻变化，可以模拟不同的温度条件。

💡校准器

校准器是一种专门用于校准测量设备的仪器，它可以提供精确的模拟信号，以检查和调整被校准设备的性能。在视频中，使用校准器来模拟RTD的电阻和测量温度变送器的4-20mA输出。

💡故障标准

故障标准是指在测量或校准过程中设定的性能标准，如果测量结果超出这些标准，则认为设备出现故障。在视频中，提到了设定故障标准为跨度的0.5%，用于评估校准结果是否合格。

💡传感器调整

传感器调整是指对传感器进行微调以确保其测量结果的准确性。在视频中，通过使用通讯器对温度变送器进行传感器调整，包括两点调整和模拟调整，以确保温度读数的准确性。

💡测试设备

测试设备是指用于测量、校准或其他测试任务的仪器或工具。在视频中，测试设备包括校准器和通讯器，它们用于校准和调整RTD温度变送器，确保其测量结果的准确性和可靠性。

💡过程控制

过程控制是指对工业生产过程中的各种参数进行监测和调整，以确保生产过程的稳定性和产品质量。温度控制是过程控制中的一个重要方面，RTD温度变送器在校准后可以用于精确控制过程中的温度。

Highlights

介绍了如何校准RTD温度变送器

使用四线RTD和变送器进行校准的基本方法

通过将探头放入加热块中来观察4-20mA输出变化

当无法移除探头时，可以模拟电阻给变送器

演示了如何使用校准器连接并测量变送器

展示了如何将4-20mA输出与0-100摄氏度进行比例换算

解释了如何通过断开探头并连接校准器进行模拟校准

详细说明了四线RTD温度元件的连接方式

介绍了如何使用校准器进行无纸化校准过程

讨论了校准失败的情况和如何通过调整来回到规范

展示了如何使用通讯器进行传感器的两点微调

强调了测试设备需要比被测试单位更精确，并且需要可追溯性

通过校准器模拟RTD并读取4-20mA输出的过程

说明了校准成功后的步骤和如何保存校准结果

提供了如何将校准结果与之前的结果结合的建议

总结了如何完成RTD温度变送器的校准并将其重新放回流程中

感谢观看并鼓励订阅YouTube频道以获取更多类似视频

Transcripts

hi it's Michael from Phoenix BMX and ISA

decided to put together this video to

show you how to calibrate this RTD

temperature transmitter calibrating RTD

transmitted is not that difficult

there are basically two options one is

it looks like this you've got a

temperature element connected to the

transmitter this is not a deep probe

it's a four wire RTD and we've we've got

it connected all we need to do right now

obviously connect our and you know 420

measurement power loop this transmitter

to get it working you would normally put

that probe into the bath into the block

and heat it up and then you will see the

full 220 output changing but sometimes

that's not possible to actually remove

the probe and put it in the bath what

can you do instead well you could

actually simulate the resistance to the

transmitter and therefore you can you

can see the four 220 out changing we're

going to do that later in this video so

I'm going to show you how to do that but

Before we jump there let me just connect

my calibrator to my transmitter so you

can actually see what the full 220

output is so let's go to the calibrator

let's connect and measure milliamps so

I'm going to be supplying 24 volts into

the transmitter and measuring for 220 as

well so let me just do that now okay so

one lead and secondly there right so it

looks as if we've got some live reading

we've got seven point six three seven

point six two milliamps output from that

transmitter so right now if we were to

you know to touch and change you know

the temperature of you put it in D and

you know a bath ice bucket of eyes

anything like that obviously that

temperature would change and milliamps

would change we could actually also see

if we scale that 4 to 20 milliamps

output to zero to 100 Celsius degrees we

can actually have the Celsius degrees as

a scaled value as well so you can see

you can you can do that and if you pod

that again in the in a baffle and if in

like that that would change

so what I'm going to do now is

disconnect this probe from the

transmitter we're going to disconnect

everything we're just going to connect

the leads back to the to the calibrator

and you will see how we can actually do

the calibration using the document and

calibrator and simulating the RTD the

probe is now going to be disconnected

from the transmitter and we are going to

connect our sets of leads and then

subsequently connect this transmitter to

a to a calibrator so this point this is

a four wire and RTD temperature element

so we're going to disconnect that and by

the way whistling here is optional you

don't have to whistle but you can if you

want right

so the MC element is off right now

quickly explained in what can we see

here and this is a normal sort of fall

to 20 RTD and temperature transmitter

you can see right now that the resistor

is is here between 1 & 2 & 3 & 4 so

that's how we're going to connect our

test leads you can see 4 to 20 so this

is where the power lead is going to go

into and this is where we're going to

read the full 20 so let's connect our

test leads

so the red ones going to go to one side

of the register and the black ones going

to go to the other okay all we have to

do right now is obviously we connected

the four wire and for test leads we're

going to connect them into the document

to calibrate it but we also want to

connect right now the power lead so

we're going to do that now so this is

going to provide a loop power to the

transmitter and also going to measure

four to twenty in the same time okay so

we're ready to connect and our test

leads to our calibrator so what we're

going to do is go to our 2d simulation

and we're going to connect the test lead

as shown on this picture

okay so let's see if we simulate zero

what's the 420 output

it seems as if the the output is working

okay so at this stage we could just you

know carry on with the calibration using

our test equipment and what what we're

going to do is go to a document in

calibrator and we want to carry on with

the paperless calibration and we

actually set up one just here and now

which is 0 to 100 4 to 20 on the airport

we've got everything connected or we

have to press right now is start and the

calibrator is going to simulate and the

resistance to the transmitter so it I

can actually you know give us a 420

output and there'll be five calibration

points going up and down you can see the

blue holograms lines these are the

passive failed criteria we set it to

point five of a percent of span and so

it looks as if and all of our points is

going to be outside of that so that's

going to mean a failed calibration but

we'd have to do something about it if we

want to bring it back to spec you can

also see the the red dots this is just

an indication that those points are

outside of our tolerance and you can see

also here that there are the calibration

points and that the calibrate is going

to simulate and four to twenty outputs

going to it's going to be measured okay

so this is our failed calibration it

looks as if we have done 0.75 percent of

span error so this is obviously greater

error than we had dissipated it's 150

percent significant error which means

that we are obviously outside of our

tolerance this value is very important

and because it shows us where we are in

terms of our tolerance and we could put

any information about it wine failed if

we know why it has happened but you can

see the graph you can see the numbers

behind the graph and now we would have

to save this this is our s found

calibration and we could also right now

finish and go and leave it as it is but

we we don't want to leave a failed

calibration so we're going to save it as

found and we're going to right now try

to bring it back

to spec and and to do another

calibration is left

this is a hard transmitter so what we're

going to do is we're going to use our

communicator that it's built in here to

actually communicate and trim the the

sensor and what you could do

alternatively if that's not too hard and

there would be usually a zero and span

screws and you would have to just go

about and try to find and adjust to get

the correct settings but here we're just

going to use our heart communicator so

let me show you how to do that and we

just start the communication so right

now the hard building modem here because

it's going to communicate it to our

transmitter it's going to give us some

options here the tags and and the ranges

but we're not interested in that we

would like to trim that transmitter so

you're going to go to diagnostic and

service we're going to go to sensor

Trinh and we're going to go to two-point

trim we recommend doing two-point trim

and because you want to do a lower and

the upper trim and we also going to do

the analog trim in there is going to be

graphic shown here somewhere so you can

just have a look at why we doing both

but they are in Syria so we have to do

both okay we just following the

instructions as they are displayed here

on the screen you just click OK and

click - another instruction you can see

right now they're at the moment at zero

it's it's built just below zero so we've

got to copy this value into this cell by

just clicking that number one there and

you click OK and it's asking us to apply

the hi and the value right now we know

the high value was hundred so we're

going to do that and again synod's

stable you click OK if you follow the

instruction you click OK again and again

you copy information from box number one

into into the sensor and you can see

right now how milliamps quickly trimmed

so it looks as if we are onto something

good here so let's just come up and

let's just do the animal trim as well

again we follow the instructions set by

our and my Oh didi files entered it in

that it's inside the transmitter okay

set the transmitter to 4 milliamps we

again copy the value we agreeing that

we've seen four milliamps and we

following the instructions as we were

before you copy the value from box

number two into it it click OK and yes I

can see 20 milliamps it looks as if we

trimmed and both digital and analog

let's go back to our test and we're

ready to do the s left calibration now

let me just check at 100 we seem around

20 milliamps it's okay what happens if I

go to the lower end you can see we had

zero reading out 4 milliamps we happy

with that so let's hit start so you can

see right now the transmitter is going

to simulate the RTD into and into it and

it's going to read the 420 out you can

see steps is going to go five step up

five step down you can see the step size

here and this actually is a very good

time to talk about calibrators itself

the test equipment what does it make

what does make test equipment test

equipment it two things one it needs to

be more accurate probably four times

more accurate than the unit on the test

that's one thing second thing it needs

to be traceable it needs to be in date

so it needs to be traceable to national

standard so we need to send it to

calibrations lab for traceability and

those two things are out of critical and

most important when we actually talking

about test equipment we need to always

bear that in mind you can see our

calibration is on the way

it slowly goes through those five point

up and five point down you can see next

point is 50 it waits eight second

actually to get this stable reading and

then it and sort of capture that value

there and then

okay so it looks as if we are well in

tolerance as opposed to previously when

we were 150% significant error out we

only 20% significant error right now so

we reduced up massively you can see it's

a passed calibration we we obviously

trimmed it that's why we we got there

you can see we can put information about

who did the calibration and any

calibration notes you can see the graph

so you can you can pretty much share say

here that we are well within tolerance

so that's all good we can save this

calibration we can actually do save this

calibration there's left we can also

combine this with the previous results

if that was the case and we can just

save it and there you have it that's how

to calibrate RTD transmitter using the

calibrator document in calibrator we've

just completed calibrating this RTD

temperature transmitter all we have to

do right now is disconnect all the

cables and put it back into the process

so I have to connect back to pro thank

you so much for watching and for more

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channel