Carlo 的WM2:
WM2-96 is a general-purpose analyzer to measure all the electrical parameters of an electrical line or load. Its user friendless allows it to be mounted in the switch and control gears as local indicator instead of the classical single function instruments. The same instrument can also be used as a remote unit to transmit the measured energy to a PLC by means of the pulse output or all the available measurements to a Personal Computer by means of the RS485 output.

该表采用modbus RTU 协议 rs485,我用s7-200的freeport 方式，
采用rcv指令接收，但总通讯不上，如果将plc程序不变，同计算机通讯则无任何问题。发送的指令也无任何问题采用其手册上的例子，接线plc的3 和8分别接该表上的
RX+/TX+,RX-/TX-.因此也看不出任何问题。希望各位提些建议。谢谢！！！