The quality of the transmitter

After the marketization of production materials for sea salt transmitters, it intensified fierce competition, and it was difficult to discriminate between true and false quality. Because transmitters were marginal disciplines, many engineering designers were relatively unfamiliar with this, and some manufacturers’ product industrial grades and civil commercial-grade indicators Confusion (Industrial-grade prices are 2-3 times that of civilian commercial grades).

Haiyan Transmitter uses the commonly used 0.5-level current and voltage transmitter as an example to identify the true and false advantages and disadvantages from the following methods:

1, the reference must be stable, 4mA is the corresponding input zero reference, reference instability, talk about the accuracy of linearity, cold start 3 minutes 4mA zero drift within 40% less than 0.5%; (ie 3.98- 4.02mA), load voltage 250Ω pressure drop of 0.995-1.005V, foreign IC chip use expensive energy gap reference, temperature drift coefficient per degree change of 10ppm; Haiyan Jinhan Electronics 2, internal circuit total consumption current <4mA, plus setting After the equal to 4.000mA, and active rectifier filter amplifying constant current circuit does not change due to changes in the primary input current consumption will also change, foreign IC chip using constant current power supply; Haiyan Jinhan Electronics 3, when the operating voltage of 24.000V, full scale At 20.000mA, full-scale 20.000mA reading will not change due to load 0-700Ω; variation does not exceed 20.000mA0.5%; Haiyan Jinhan Electronics 4, when full scale 20.000mA, load 250Ω, full scale The reading of 20.000mA will not change due to a change in the operating voltage of 15.000V-30.000V; the change does not exceed 20.000mA within 0.5%; Haiyan Jinhan Electronics 5. When the primary side is overloaded, the output current does not exceed 25.000mA+10% , otherwise PLC/DCS for transmitter 2 The 4V power supply and A/D input clamp circuit are damaged due to excessive power consumption. In addition, the transmitter output is also damaged due to excessive power consumption. The A/D input clamp circuit is even more vulnerable. Jinhan Electronics 6. When the working voltage is 24V reversed, it must not damage the transmitter and must have polarity protection;

7, when the two lines due to induction and induced surge voltage exceeds 24V to clamp, do not damage the transmitter; generally in parallel between the two lines 1-2 TVS transient protection diode 1.5KE can inhibit every 20 The pulse of positive and negative pulse of 20 millisecond pulse width of one time interval of one second, transient withstand impact power 1.5KW-3KW; Haiyan Jinhan Electronics 8, the linearity of 0.5% of product marking is absolute error or relative error, can be according to the following method The identification can be seen at a glance. 9. The current limit must be limited when the primary input is overloaded:

When the primary input overload is greater than 125%, the output overcurrent limit 25mA+10% (25.00-27.50mA) load 250Ω pressure drop is 6.250-6.875V;

10, whether the sensing surge voltage exceeds 24V when there is no clamping recognition: In the two-wire output port and an AC 50V pointer meter, with AC 50V then two lines to instantly touch the two-wire output port, see if there is no clamp Bit, how many volts can be clamped at a glance.

11, with or without polarity protection identification: with an analog multimeter multimeter by 10K positive and negative measurement of the two-wire output port, there is always an infinite resistance Ω, there is polarity protection;

12. Long-time short-circuit protection with infinite output current: when the primary input is 100% or when the overload is greater than 125%-200%, the load is short-circuited to 250Ω and the short-circuit protection limit is measured at 25mA+10%; Haiyan Jinhan Electronics 13, Industrial Level and civil commercial level discrimination: The industrial grade operating temperature range is -25 degrees to +70 degrees, the temperature drift coefficient is 100ppm per degree, ie, the temperature changes by 1 degree per degree, and the accuracy changes to one ten-thousandth; the civil commercial level The operating temperature range is 0 degrees (or -10 degrees) to +70 degrees (or +50 degrees). The temperature drift coefficient is 250 ppm per degree, that is, the temperature changes by 1 degree per degree, and the accuracy changes to 2.5 per cent. The temperature drift coefficient of the current and voltage transmitters can be tested and verified with an incubator or high-low temperature box.

The above method can also be used to distinguish between true and false advantages and disadvantages of other transmitters. Haiyan Jinhan Electronics manufactures FP/GP/EP series transmitters, adopts a full set of high-quality components such as ASIC chip (special transmitter thick film circuit), super-linear voltage, and current transformer, together with a full set of high-precision production equipment and computer detection. Calibration system, according to the international quality assurance system ISO 9001:2000 assembly production, specifications, high taste. There are voltage, current, active power, reactive power (spanning or sinusoidal reactive power), active power, reactive power, frequency, power factor, DC voltage, DC current, power total adder, etc. Sender. This series of transmitters has a high degree of integration, works more reliably, has excellent temperature characteristics and long-term stability, good resistance to electrical shock and overload capacity, a high level of accuracy and linearity, is a type that does not require regular school Tested and maintained, fully reliable and ideal third-generation power transmitter. FP series transmitters meet the requirements of IEC, ANSI, BEAMA and other related standards and reach the advanced level of similar products in the world.