How to solve the inverter air conditioner E6 communication fault with a multimeter
What is communication fault? Power on within 15S, the inside unit can not receive the data sent by the outside unit; or during operation, the indoor unit does not receive the correct data sent by the outdoor unit for 3 consecutive minutes, then a communication fault E6 is generated.The company's inverter air conditioner adopts a communication circuit in the form of a current loop, which can be simplified and modelled to understand according to the following diagram, so that if U1 is normally open, then the switch of U4 can be synchronised with that of U3, so that if U3 is normally open, the switch of U1 can be synchronised with that of U2. U2 synchronisation. Control the switching time sequence of each optocoupler, the digital signal communication can be achieved indoors and outdoors.
How to check with a multimeter? Share a few experiences:
Step 1: After powering up and switching on the unit, use the AC file of the multimeter to test whether the external unit is electrified , and whether the L-N voltage is normal? --------- If it is not electrified, check the inner machine or inner and outer machine connecting wires;
Step 2: Voltage normal for the following test
Step 3: multimeter DC file test N-COM voltage, the voltage is 0, communication power supply circuit is bad or the external controller power terminals are not plugged in, check the external electrical box of the power supply terminal connections, confirm the replacement;
Step 4: multimeter DC file test N-COM voltage, the voltage is about 3.7V fixed value, the main chip of the external machine has no output, check the connection of each power supply wiring and load terminal of the external machine electrical box, confirm the replacement;
Step 5: Multimeter DC file test N-COM voltage, voltage jumps between 30V-56V, no signal feedback from the inner machine, check the connection of each terminal of the main board of the inner machine, confirm the replacement;
Step 6: the above conditions are normal, change a separate COM cable, see if the internal and external machine can communicate normally, to rule out the influence of the line.
Note 1: Some faulty motherboards may have 470K resistor vulcanisation or silver migration problems, after the resistor vulcanisation, the voltage value above may produce changes.
Note 2: Under normal circumstances, the multimeter DC file to test the voltage between N-COM, the voltage will be between 5V-30V-56V regular jumps.
