生產(chǎn)資料市場化以后，加劇激烈的競爭，真假優(yōu)劣難辨，又因變送器是邊緣學(xué)科，很多工程設(shè)計人員對此較陌生，有些廠家產(chǎn)品工業(yè)級別和民用商用級別指標(biāo)混淆（工業(yè)級的價格是民用商用級的2-3倍）
After the marketization of the means of production, fierce competition has intensified, and it is difficult to distinguish between the true and the false. Because the transmitter is a marginal discipline, many engineering designers are unfamiliar with it. Some manufacturers confuse the industrial level and commercial level indicators of their products (the price of industrial level is 2-3 times that of commercial level)
以常用的0.5級精度的電流電壓變送器為例，從以下方法著手來辨別真假優(yōu)劣。
Taking the current and voltage transmitter with 0.5 level accuracy as an example, the following methods are used to distinguish the true and the false.
(1)基準(zhǔn)要穩(wěn),4mA是對應(yīng)的輸入零位基準(zhǔn)，基準(zhǔn)不穩(wěn)，談何精度線性度，冷開機(jī)3分鐘內(nèi)4mA的零位漂移變化不超過4.000mA0.5%以內(nèi);(即3.98-4.02mA),負(fù)載250Ω上的壓降為0.995-1.005V，國外IC心片多用昂貴的能隙基準(zhǔn)，溫漂系數(shù)每度變化10ppm；
(1) The benchmark should be stable. 4mA is the corresponding input zero benchmark. The benchmark is not stable. How about the accuracy linearity? The zero drift change of 4mA within 3 minutes after cold start is not more than 4.000ma 0.5%; (i.e. 3.98-4.02ma). The pressure drop on the load 250 Ω is 0.995-1.005v. Foreign IC chips mostly use expensive energy gap benchmark, and the temperature drift coefficient changes 10ppm per degree;
(2)內(nèi)電路總計消耗電流<4mA,加整定后等于4.000mA,而且有源整流濾波放大恒流電路不因原邊輸入變化而消耗電流也隨之變化，國外IC心片采用恒流供電；
(2) The total current consumption of the internal circuit is less than 4mA, which is equal to 4.000ma after setting. Moreover, the current consumption of the active rectifier filter amplification constant current circuit does not change due to the change of the original side input. The foreign IC core adopts constant current power supply;
(3)當(dāng)工作電壓24.000V時,滿量程20.000mA時,滿量程20.000mA的讀數(shù)不會因負(fù)載0-700Ω變化而變化;變化不超過20.000mA0.5%以內(nèi)；
(3) When the working voltage is 24.000v and the full range is 20.000ma, the reading of the full range is 20.000ma, which will not change due to the change of load 0-700 Ω; the change is not more than 20.000ma 0.5%;
(4)當(dāng)滿量程20.000mA時,負(fù)載250Ω時,滿量程20.000mA的讀數(shù)不會因工作電壓15.000V-30.000V變化而變化;變化不超過20.000mA0.5%以內(nèi)；
(4) When the full scale is 20.000ma and the load is 250 Ω, the reading of the full scale is 20.000ma, which will not change due to the change of the working voltage 15.000v-30.000v; the change is not more than 20.000ma 0.5%;
(5)當(dāng)原邊過載時，輸出電流不超過25.000mA+10%以內(nèi)，否則PLC/DCS內(nèi)供變送器用的24V工作電源和A/D輸入箝位電路因功耗過大而損壞，另外變送器內(nèi)的射隨輸出亦因功耗過大而損壞，無A/D輸入箝位電路的更遭殃；
(5) When the primary side is overloaded, the output current shall not exceed 25.000ma + 10%. Otherwise, the 24V working power supply and a / D input clamping circuit for the transmitter in PLC / DCS will be damaged due to excessive power consumption. In addition, the output of the transmitter will also be damaged due to excessive power consumption, and there will be no further damage to the A / D input clamping circuit;
(6)當(dāng)工作電壓24V接反時不得損壞變送器,必須有極性保護(hù);
(6) When the working voltage is connected reversely at 24V, the transmitter shall not be damaged, and polarity protection must be provided;
(7)當(dāng)兩線之間因感應(yīng)雷及感應(yīng)浪涌電壓超過24V時要箝位,不得損壞變送器；一般在兩線之間并聯(lián)1-2只TVS瞬態(tài)保護(hù)二極管1.5KE可抑制每20秒間隔一次的20毫秒脈寬的正反脈沖的沖擊,瞬態(tài)承受沖擊功率1.5KW-3KW;
(7) When the induced lightning and induced surge voltage between two lines exceed 24V, clamp them and do not damage the transmitter; generally, 1-2 TVs transient protection diodes 1.5ke in parallel between two lines can suppress the impact of positive and negative pulse with 20 millisecond pulse width every 20 seconds, and the transient withstand impact power is 1.5kw-3kw;
(8)產(chǎn)品標(biāo)示的線性度0.5％是絕對誤差還是相對誤差,可以按以下方法來辨別方可一目了然:符合下述指針是真的線性度0.5％.
(8) Whether the linearity of 0.5% of the product mark is absolute error or relative error can be identified at a glance by the following methods: the true linearity of 0.5% conforms to the following indicators
原邊輸入為零時輸出4mＡ正負(fù)0.5%(3.98-4.02mA),負(fù)載250Ω上的壓降為0.995-1.005V
When the primary input is zero, the output is 4mA plus or minus 0.5% (3.98-4.02ma), and the pressure drop on the load 250 Ω is 0.995-1.005v
原邊輸入10％時輸出5.6mＡ正負(fù)0.5%(5.572-5.628mA)負(fù)載250奧姆上的壓降為1.393-1.407V
Output 5.6ma plus or minus 0.5% (5.572-5.628ma) with 10% primary input, the pressure drop on the load 250 OM is 1.393-1.407v
原邊輸入25％時輸出8mＡ正負(fù)0.5%(7.96-8.04mA)負(fù)載250Ω上的壓降為1.990-2.010V
When the primary input is 25%, the output 8Ma is plus or minus 0.5% (7.96-8.04ma). The pressure drop on the load 250 Ω is 1.990-2.010v
原邊輸入50％時輸出12mＡ正負(fù)0.5%(11.94-12.06mA)負(fù)載250Ω上的壓降為2.985-3.015V
When the primary input is 50%, the output is 12mA plus or minus 0.5% (11.94-12.06ma). The pressure drop on the load 250 Ω is 2.985-3.015v
原邊輸入75％時輸出16mＡ正負(fù)0.5%(15.92-16.08mA)負(fù)載250Ω上的壓降為3.980-4.020V
When the primary input is 75%, the output 16mA is plus or minus 0.5% (15.92-16.08ma). The pressure drop on the load 250 Ω is 3.980-4.020v
原邊輸100％時輸出20mＡ正負(fù)0.5%(19.90-20.10mA)負(fù)載250Ω上的壓降為4.975-5.025V
When the primary side input is 100%, the output 20mA is plus or minus 0.5% (19.90-20.10ma), and the pressure drop on the load 250 Ω is 4.975-5.025v
(9)原邊輸入過載時必須限流:原邊輸入過載大于125%時輸出過流限制25mＡ+10%(25.00-27.50mA)負(fù)載250Ω上的壓降為6.250-6.875V；
(9) The current must be limited when the primary input overload is greater than 125%. When the primary input overload is greater than 125%, the output overcurrent is limited to 25mA + 10% (25.00-27.50ma). The pressure drop on the load 250 Ω is 6.250-6.875v;
(10)感應(yīng)浪涌電壓超過24V時有無箝位的辨別:在兩線輸出端口并一個交流50V指針式表頭,用交流50V接兩根線去瞬間碰一下兩線輸出端口,看有無箝位,箝位多少伏可一目了然啦;
(10) Identify whether there is clamping when the induced surge voltage is more than 24V: connect two lines of AC 50V output port with an AC 50V pointer meter, and touch the two lines of output port with two lines of AC 50V in an instant to see if there is clamping, and the clamping voltage can be seen at a glance;
(11)有無極性保護(hù)的辨別:用指針式萬用表Ω乘10K檔正反測量兩線輸出端口,總有一次Ω阻值無限大,就有極性保護(hù)；
(11) Identification of whether there is polarity protection or not: measure the two-wire output port by multiplying 10K gear with the pointer multimeter Ω, and once the Ω resistance is infinite, there is polarity protection;
(12)有無極輸出電流長時間短路保護(hù)：原邊輸入100％時或過載大于125%-200%時，將負(fù)載250Ω短路，測量短路保護(hù)限制是否在25mＡ+10%；
(12) Long time short circuit protection with or without pole output current: when the primary side input is 100% or the overload is greater than 125% - 200%, short circuit the load 250 Ω, and measure whether the short circuit protection limit is 25mA + 10%;
(13)工業(yè)級別和民用商用級別的辨別:工業(yè)級別工作溫度范圍是-25度到＋７0度，溫漂系數(shù)是每度變化100ppm,即溫度每度變化1度,精度變化為萬分之一；民用商用級別工作溫度范圍是0度（或-10度）到＋７0度（或+50度）,溫漂系數(shù)是每度變化250ppm,即溫度每度變化1度,精度變化為萬分之二點五；電流電壓變送器的溫漂系數(shù)可以用恒溫箱或高低溫箱來試驗驗證較繁瑣。
(13) Identification of industrial grade and commercial grade: the working temperature range of industrial grade is - 25 ° C to + 70 ° C, and the temperature drift coefficient is 100ppm per degree change, i.e. the temperature changes by 1 ° C, and the accuracy changes by 1 / 10000; the working temperature range of commercial grade is 0 ° C (or - 10 ° C) to + 70 ° C (or + 50 ° C), and the temperature drift coefficient is 250PPM per degree change, i.e. the temperature changes by 1 ° C, The accuracy changes to 2.5% of 10000; the temperature drift coefficient of current and voltage transmitter can be verified by constant temperature box or high and low temperature box test.
華恒儀表制造廠家憑借專業(yè)技術(shù)優(yōu)勢，可靠穩(wěn)定的產(chǎn)品質(zhì)量，堅持大限度的滿足用戶的需求是企業(yè)發(fā)展的動力源泉，以優(yōu)質(zhì)專業(yè)的服務(wù)為我國電力、石油、化工、冶金、水泥、礦業(yè)、市政、造紙等行業(yè)提供了高性能價格比的工業(yè)自動化儀表產(chǎn)品。為我國自動化儀表的發(fā)展做出了重要貢獻(xiàn)。
Relying on the advantages of professional technology, reliable and stable product quality, Huaheng instrument manufacturer insists on meeting the needs of users to a large extent, which is the power source of enterprise development. With high-quality professional services, it provides industrial automation instrument products with high performance price ratio for China's electric power, petroleum, chemical industry, metallurgy, cement, mining, municipal administration, papermaking and other industries. It has made an important contribution to the development of automatic instruments in China.