How to deal with the fault of capacitive pressure transmitter?Xi'an Huaheng Instrument Manufacturing Co.,Ltd.Introduction:Transmitter measurement part inspection:Transmitter measurement part of the failure,will cause no output or output abnormal transducer,so we should first check the transducer measurement sensitive components.

 

　　1．拆下法蘭，檢查敏感部件隔離膜片有無變形，破損和漏油現(xiàn)象發(fā)生。

　　2．拆下補(bǔ)償板，不取出敏感部件，檢查插針對殼體的絕緣電阻，在電壓不超過100V的情況下，絕緣電阻不應(yīng)小于100MΩ。

　　3．接通電路和氣路，當(dāng)壓力信號為量程上限值時，關(guān)閉氣源，輸出電壓和讀數(shù)值應(yīng)穩(wěn)定不動。如果輸出電壓下降，則說明變送器有泄漏，可用肥皂水檢查出泄漏部位。

 

　　1.Remove the flange and check whether the diaphragm of the sensitive parts is deformed,damaged and oil leakage.

　　2.Remove the compensating plate,do not take out the sensitive parts,check the insulation resistance inserted into the shell,in the case of voltage not exceeding 100V,the insulation resistance should not be less than 100M.

　　3.Turn on the circuit and gas circuit.When the pressure signal is the upper limit of the range,turn off the gas source,and the output voltage and reading value should be stable.If the output voltage drops,it means that the transmitter has leakage,and the leak can be detected with soapy water.

 

　　變送器電路部分的檢查：

 

　　Check the circuit part of the transmitter:

 

　　1．接通電源，檢查變送器輸出端電壓信號的狀態(tài)。若無輸出電壓，應(yīng)首先檢查電源電壓是否正常；是否符合供電要求；電源與變送器及負(fù)載設(shè)備之間有無接線錯誤。如果變送器接線端子上無電壓或極性接反均可造成變送器無電壓信號輸出。排除上述原因，則應(yīng)進(jìn)一步檢查放大器板線路中元件有無損壞問題；線路板接插件有無接觸不良現(xiàn)象，可采取對照正常儀表的測量電壓與故障儀表對應(yīng)的測量電壓相比較的方法，確定故障點(diǎn)，必要的情況下可更換有故障的放大器板。在對流量型變送器檢查時，對J型放大器板應(yīng)特別要注意采取防靜電措施。

 

　　1.Turn on the power supply and check the state of the output voltage signal of the transmitter.If there is no output voltage,it should first check whether the power supply voltage is normal;whether it meets the requirements of power supply;whether there are wiring errors between power supply and transmitter and load equipment.If there is no voltage or polar connection on the terminal of the transmitter,no voltage signal output of the transmitter can be produced.In order to eliminate the above reasons,it is necessary to further check whether the components in the circuit of amplifier board are damaged or not;if the circuit board connectors are not in good contact,the method of comparing the measured voltage of normal instrument with the corresponding measured voltage of fault instrument can be adopted to determine the fault point,and if necessary,the faulty amplifier board can be replaced.When checking the flow transducer,special attention should be paid to the anti-static measures for the J-type amplifier board.

 

　　2．接通電源，在給定輸入壓力信號后，若變送器輸出過高（大于10VDC），或輸出過低（小于2.0VDC），且改變輸入壓力信號和調(diào)整零點(diǎn)、量程螺釘時輸出均無反應(yīng)。對于這類故障，除檢查變送器測量部分敏感部件有無異常外，應(yīng)檢查變送器放大器板上“振蕩控制電路部分”工作正常與否。高頻變壓器T1-12之間正常峰值電壓應(yīng)為25~35VP-P；頻率約為32kHz。其次檢查放大器板上各運(yùn)算放大器的工作狀況；各部分的元器件有無損壞問題等。此類故障需要更換放大器板。

 

　　2.Turn on the power supply,if the output of the transmitter is too high(greater than 10VDC)or too low(less than 2.0VDC)after the given input pressure signal,the output will not respond when the input pressure signal is changed and the zero and range screw is adjusted.For such faults,besides checking whether the sensitive parts of the transducer measurement part are abnormal,the"oscillation control circuit"on the transducer amplifier board should be checked whether it works properly or not.The normal peak voltage between T1-12 of high frequency transformer should be 25-35 VP-P,and the frequency should be about 32 kHz.Secondly,check the working condition of the operational amplifiers on the amplifier board;the components of each part have no damage problems,etc.This kind of fault requires replacing the amplifier board.

 

　　3．變送器在線路設(shè)計和工藝裝配質(zhì)量上要求都十分嚴(yán)格，在實(shí)際使用中對出現(xiàn)的線路故障，經(jīng)檢查確認(rèn)后最好與生產(chǎn)廠家聯(lián)系更換其故障線路板，以確保儀表長期工作的穩(wěn)定性和可靠性。

 

　　3.Transmitter has strict requirements in line design and process assembly quality.In the actual use of line faults,it is better to contact the manufacturer to replace the faulty circuit board after checking and confirming,so as to ensure the stability and reliability of the instrument in long-term operation.

 

　　現(xiàn)場故障檢查：

　　施工現(xiàn)場出現(xiàn)的故障，絕大多數(shù)是由于使用和安裝方法不當(dāng)引起的，歸納起來有幾個方面。

 

　　On-site fault check:

　　Most of the faults on the construction site are caused by improper use and installation methods,which can be summed up in several aspects.

 

　　1．一次元件（孔板、遠(yuǎn)傳測量接頭等）堵塞或安裝形式不對，取壓點(diǎn)不合理。

　　2．引壓管泄漏或堵塞，充液管里有殘存氣體或充氣管里有殘存液體，變送器過程法蘭中存有沉積物，形成測量死區(qū)。

　　3．變送器接線不正確，電源電壓過高或過低，指示表頭與儀表接線端子連接處接觸不良。

　　4．沒有嚴(yán)格按照技術(shù)要求安裝，安裝方式和現(xiàn)場環(huán)境不符合技術(shù)要求。

 

　　1.The blockage or installation of primary components(orifice plate,remote transmission measuring joint,etc.)is not correct,and the pressure point is unreasonable.

　　2.Leakage or blockage of pressure pipes,residual gas in liquid filling pipes or residual liquid in gas filling pipes,and sediment in flange of transducer process form dead zone of measurement.

　　3.The transmitter connection is incorrect,the power supply voltage is too high or too low,indicating that the contact between the meter head and the instrument terminal is not good.

　　4.Installation is not strictly in accordance with the technical requirements.Installation methods and site environment do not meet the technical requirements.

 

　　以上出現(xiàn)的故障都會引起變送器輸出不正?；驕y量不準(zhǔn)確，但經(jīng)過細(xì)心檢查，嚴(yán)格按照技術(shù)要求使用和安裝，及時采取有效措施，問題都可以排除，對不能處理的故障，應(yīng)將變送器送到實(shí)驗室或生產(chǎn)廠家做進(jìn)一步檢查。

 

　　Above faults will cause abnormal output or inaccurate measurement of the transmitter,but after careful inspection,strict use and installation in accordance with technical requirements,timely and effective measures can be taken to eliminate the problems.For failures that cannot be handled,the transmitter should be sent to the laboratory or manufacturer for further inspection.