Design and implementation of small PLC analog quantity output module of domestic processor

In order to solve the problems that an existing small PLC analog quantity output module is not rich enough in application scene, single in signal type, poor in autonomous controllability and the like, the small PLC analog quantity output module based on the ARM architecture domestic processor is provided, and the system comprises a microprocessor, an optical coupling isolator, a FLASH, an SPI, a DAC conversion chip and a current/voltage switch. Firstly, an analog quantity output module obtains calibration coefficients a and b through a calibration process, then calibration data are stored in a flash specific address, an instruction value output by an upper computer passes through a code value conversion module, the calibration coefficients a and b are substituted into a code value conversion formula to be converted into an original code value capable of being recognized by a DAC chip, and the original code value is stored in a flash specific address. And the original code value is written into a DAC chip thro