If the external acquisition voltage is not connected, the output current will only have 3 to 4 MA fluctuations, which is acceptable. Moreover, when the load is connected, the measured current value is also very accurate. But in the no-load state, the current value increases as the external sampling input voltage increases.
Sampling resistor is 2mR alloy resistor, 2512 package
Previously, using a 100mR sampling resistor, the current was calculated directly by reading the voltage across the resistor. Later, the acquisition resistor was replaced by 2mR because of the overcurrent problem.
Below are two actual measured graphs, the first input is 18V and the second input is 24V.