Abstract: There are many mini-PLCs of various brands applied on the field equipments for SMEs,but the communication of different brand PLCs has no interoperability.Considering the monitoring requirement of production data in SMEs,a communication system is designed among PC and different brand mini-PLCs to monitor the production process by using CAN-bus and programming port protocol owned by each PLC,and it is realized with MC68HC908GZ60 micro controller as kernel chips.Without changing the current situation of the equipments,the goal of low-cost information reform for field management is achieved,which provide a low-cost plan for SMEs to realize information reform for field management.

Key words: field management informatization, SMEs CAN, Programmable Logic Controller(PLC), MC68HC908GZ60 microcontroller unit