Overall performance:
1. Use 2.6 inches 320X240 resolution display. The surface glass has no touch function.
2. The voltage is divided by 27K to 2.7K 1:11, so the voltage range is 3.3*11=36.3V, and the 12-bit AD of the single-chip microcomputer is used, so the sampling resolution is 36.3V/4096=0.00886V, because the accuracy of AD is +- 3LSB, although over-sampling and other means are used to ensure accuracy, the jitter within +-0.027V is a normal accuracy; (this range refers to the measurement of the battery, in fact, the ripple of many power supplies of 27mV cannot be guaranteed);
3. The current uses a sampling resistor of 25 milliohms, and the amplifier resistor divider ratio of the op amp is: 1.5K: 27K, which is 19 times magnification. Therefore, the calculated current is about 6.9A. In order to ensure a certain margin, we define the header The full mass production is 5A; the same current resolution is about 1.7mA, +-3LSB is +-5.4mA;
4. Dual-channel common ground design, the meter head uses +5V power supply, which can be connected to the serial port, but the power ground must be connected to MainGND, otherwise the measurement will be inaccurate;
5. The position of the A004 module is still reserved on the board, so that the power supply range of the meter head can be extended to 28V (data data, the actual recommendation is not to exceed 24V), so that you can "steal power" from the measured voltage;
6. Onboard dual MOS, you can set the upper and lower limits of voltage and current through GPU statements, and can control MOS tubes, which is convenient for making temperature control instruments;
7. With dual-channel measurement of AH and WH, with MOS tube, it is actually very easy to make a procedure similar to lithium battery discharge capacity test;
DIY shunt can be up to 60V 50A
8. Because this product cross-mode electricity and digital electricity requires cross-industry knowledge, direct customer service is not provided by Wangwang. If you have any questions, please go to the Yile Electronics Forum to discuss
Notice:
1. The thick line represents the power line, and the large current is used. If the circuit is 5A, ensure that the line and pad of the thick line can withstand the current of 5A for a long time;
2. The two circuits share the same ground; the power supply can also be changed to 1 circuit, which can carry 2 circuits of loads;
3. Since the 5V power supply is connected to 1117 to 3.3V, and 5V is directly connected to OP07, these two devices can work normally under 10V, so 5V can be connected to a slightly higher point, such as (6V), but be sure Stable, otherwise the offset of OP07 under different voltages will be different, causing the need to recalibrate.