Pololu ACS37041 3.3V – сензор за ток, -30A to +30A

Модул за двупосочно измерване на постоянен и променлив ток в диапазон от -30 A до +30 A, базиран на сензор с Hall ефект Allegro ACS37041KLHBLT-030B3. Токовият път е електрически изолиран от захранването и аналоговия изход на модула, а ниското му съпротивление ограничава загубите и нагряването при протичане на по-висок ток. Сензорът работи със захранващо напрежение 3V – 3,6V и има аналогов изход. При 0А ток изходното напрежение е около 1,65V (при захранване 3,3V), като при протичане на ток в посока IP+ към IP- напрежението се повишава, а при протичане на ток в обратна посока се понижава. Чувствителността е 44 mV/A и измереният ток може да се изчисли със следната примерна формула IP = (VOUT – 1.65V) / 0.044. Комплектът съдържа: Сензор за ток Pololu ACS37041 3,3V – 1 бр. Важно: Модулът е предназначен основно за измерване във вериги с напрежение под 30V. Въпреки че използваният сензор има номинално изолационно напрежение 100 V RMS, платката не е сертифицирана по конкретен стандарт за електрическа безопасност. Работа при напрежение над 24V може да бъде опасна и трябва да се извършва само от квалифицирани лица, с подходящо оборудване и защитни мерки! При продължителен ток над 20A е препоръчително да се следи температурата на модула и при необходимост да се осигури допълнително охлаждане. Дебели запоени проводници или добре затегнати кабелни обувки подпомагат отвеждането на топлината и намаляват нагряването. Характеристики: Сензор: Allegro ACS37041KLHBLT-030B3 Метод на измерване: Hall ефект Измерван ток: постоянен или променлив Диапазон на измерване: маскимум от -30A до +30A (при продължителен ток над 20A е препоръчително да се следи температурата на модула и при необходимост да се осигури допълнително охлаждане!) Захранващо напрежение: 3V – 3,6V Изход: аналогов, около 1,65 V при 0A (при захранване 3,3V); повишава се при ток от IP+ към IP- и се понижава при ток в обратната посока Чувствителност: 44 mV/A Изчисляване на тока: I = (VOUT – 1.65V) / 0.0667 Честотна лента: 150 kHz Време за реакция: под 5 µs Електрическа изолация на токовия път Съпротивление на токовия път: около 1,6 mΩ Препоръчително напрежение на измерваната верига: под 30V Номинално изолационно напрежение на сензора: 100V RMS Работна температура: от -40°C до +125°C Размери платка: 17,8 х 20,3 mm Допълнителна информация: Pololu ACS37041KLHBLT-030B3 Current Sensor Compact Carrier -30A to +30A, 3.3V. Подробно описание, ръководство ACS37041/2 datasheet (pdf) Схема (pdf) Размери (page 2) (pdf) Overview EN: Hall effect-based sensor with electrically isolated current path allows the sensor to be inserted anywhere along the current path and to be used in applications that require galvanic isolation. Low primary current path resistance of 1.6 mΩ in the sensor IC, so very little power is lost in the module. Differential Hall sensing rejects common-mode fields, so the orientation of the sensor relative to uniform external magnetic fields (e.g. the Earth’s magnetic field) has less effect on the measurement. 150 kHz bandwidth analog output voltage proportional to AC or DC currents. Less than 5 µs response time. Output is not ratiometric (i.e. the zero point and sensitivity are independent of the actual supply voltage), which provides immunity from noisy supplies. Integrated temperature compensation circuitry allows improved accuracy over the full operating temperature range. Automotive-grade operating temperature range of -40°C to 125°C. Carrier boards, available in micro (0.3″×0.4″) and our standard compact (0.7″×0.8″) sizes, offer a variety of ways to insert it into the current path along with 0.1″-pitch (breadboard-compatible) power, ground, and output pins. Using the sensor This sensor has five required connections: the input current (IP+ and IP-), logic power (VDD and GND), and the sensor output (VOUT). The sensor requires a supply voltage of 3 V to 3.6 V to be connected across the VDD and GND pads, which are labeled on the bottom silkscreen. The sensor outputs an analog voltage on VOUT that is centered at 1.65 V and changes by 44mV per amp of input current, with positive current increasing the output voltage and negative current decreasing the output voltage: The output is not ratiometric, so the zero point and sensitivity are independent of the actual supply voltage. Making connections to the board You can insert the board into your current path in a variety of ways. For typical high-current applications, you can solder wires directly to the through-holes that best match your wires, or you can use solderless ring terminal connectors. The largest through-holes are big enough for 10 AWG wires or #6 or M3.5 screws, and the second-largest through-holes (and mounting holes) are sized for 14 AWG wires or #2 or M2 screws. Holes with 0.1″, 3.5 mm, and 5 mm spacing are also available as shown in the diagram above for connecting male header pins or terminal blocks, but please note that these connection options will generally not be suitable for the kinds of high currents intended for this sensor. The pictures below show examples of various connection options with the ACS37220 compact carrier, which has the same physical dimensions as the ACS37041/ACS37042 compact carrier. The VOUT, VDD, and GND pins work with 0.1″-pitch header pins and are compatible with standard solderless breadboards Isolation rating and board creepage considerations The ACS37041 and ACS37042 differ in their manufacturer-rated isolation voltages of 100 VRMS and 285 VRMS, respectively. Both IC packages have a creepage of 1.6 mm, and our ACS37042 carrier PCB has a routed slot under the IC to provide a PCB creepage of 3.0 mm. (The PCB creepage on the ACS37041 carrier is the same 1.6 mm as the IC package itself.) A rough rule of thumb is that uncontaminated FR4 PCBs should have roughly 1 mm of creepage per 100 VRMS of isolation. Please note that these carrier boards are not certified to any particular safety standard. Warning: This product is generally intended for use below 30 V, and many of the application example pictures (e.g. use on a breadboard) are appropriate for such lower-voltage applications. These boards can be used at higher voltages, but working with higher voltages can be extremely dangerous and should only be attempted by qualified individuals with appropriate equipment and experience. Schematic ACS3704x Current Sensor Carrier schematic diagram. Real-world power dissipation considerations In our tests, we found that the micro carrier boards (cs08a and cs08c) could conduct about 25 A continuously, and compact carrier boards (cs08b and cs08d) could conduct about 30 A continuously, without reaching the thermal limit for the IC. Our tests were conducted at approximately 25°C ambient temperature with no forced air flow. The actual current you can pass through the sensor will depend on how well you can keep it cool. The carrier’s printed circuit board is designed to help with this by drawing heat out of the sensor chip. Solid connections to the current path pins (such as with thick soldered wires or large, tightly-secured lugs) can also help reduce heat build-up in the sensor and carrier board. Warning: Exceeding temperature or current limits can cause permanent damage to the sensor. If you are measuring an average continuous current greater than 20 A, we strongly recommend that you monitor the sensor’s temperature and look into additional cooling if necessary. This product can get hot enough to burn you long before the chip overheats. Take care when handling this product and other components connected to it.