A low cost and easy to implement 24-channel program controlled resistance output solution based on STM32F103RCT6 chip is proposed in order to continuously output multichannel resistors with different resistance values in the automatic test system of power components in an aerospace project.With the advantage of 74HC595 shift buffer
the on-off of relay resistance network is controlled to realize multi-channel resistance output under the condition of limited I/O port resources.Through MAX232 chip and Modbus protocol communication
24 expected resistance values can be quickly and accurately output.The test results show that the developed program-controlled resistance device can provide resistance output within 1666.65 kΩ
with a resolution of 10 Ω and an accuracy of less than 0.1%.It is small in size