Answer: when the module is applied, such as direct plug-in welding, it is forbidden to use strong current lines on the PCB 

surface at the bottom of the module, and try to avoid wiring. There is a one-to-one correspondence between the modules 

and their supporting transformers. This relationship binds them together during factory calibration (hardware differences 

are calibrated during calibration). Therefore, there is no saying that the transformers between the two modules can be 

interchanged or the customers can directly purchase the transformers for replacement. Such products cannot guarantee 

accuracy.