Chapter One: The introduction of electrical system and exclusion methods for impossible troubles-II. The introduction of electrical elements-8


Malfunction 1 , No communicate warning on the touch screen.

Failure 1-1: PLC power supply is disconnected, there is

no input power supply or the PLC run switch is not turned on, leading to the PLC is not working.

Solution 1-1: Check the POWER and RUN indicator is

normally ON or not, check the power supply and PLC operation switch (normal, up allocated for the working state.) to solve the problem.

If under normal working, the indicator of POWER AND RUN should be on,

If the indicator of POWER is not ON, may be the PLC power supply is disconnected or the PLC inside is get damaged.

If the indicator of RUN is not on, maybe the operation switch not in position or the CPU gets damaged.

Failure 1-2: The data line between the touch screen and PLC

is disconnected.

Solution 1-2: Check or replace the data line.

Failure 1-3: PLC gets damaged.

Solution 1-3: If the PLC power supply or the switch is in normal, while the indicator of POWER and RUN is not ON, then it can be sure that the PLC gets damaged. Remove the PLC to repair or replace it.

Malfunction 2, PLC inputs and outputs have problem. (POWER and RUN indicator is normally ON)

Failure 2-1: No input in the PLC, input terminal light is not ON.

Solution 2-1: The input line has voltage, when connect to the input terminal, the indicator does not light. Connect the damaged input terminal to other spared input terminal or replace the PLC.

Failure 2-2: the PLC has input but no output , the input terminal lights bright, the output terminal does not light.

Failure 2-2-1: The parameter setting in the touch screen incorrectly. (For example , the “raking ” is set to ‘ban’; product selection errors or color feeding device selection errors.)

Solution2-2-1: Check the corresponding parameters, do the right setting.

Failure 2-2-2: PLC output terminal get damaged.

Solution 2-2-2: from the program, connect the damaged output terminal to other spared output terminal, or replace it.

Failure 2-3: PLC input terminal is abnormal, without any external input-signal, some input terminals indicator should not light, was still on, causing the PLC with incorrect input signal, resulting in the equipment doesn’t work properly.

Failure 2-3: input terminal relay short circuit, causing the error signal input.

Solution 2-3: Remove the PLC to repair or replace it.

Failure 2-4: PLC output terminals is abnormal .The indicator should not be ON, but always ON when there is input signal or no input signal, some input terminal  indicator  should  not light,  was still on (flashing or is always on.), Resulting in PLC to make false judgments , resulting in the equipment doesn’t work properly.

Failure 2-4: Relay output terminal short circuit, resulting in the error signal output, resulting in mistake.

Solution 2-4: Remove the PLC to repair or replace it.

Malfunction 3, Touch screen display is normal, but all the indicator of proximity switches and photoelectric switch are no working.

Failure 3-1: Air cord loose or the control circuit is disconnected.

Solution 3-1: Check the control circuit with multimeter.

Failure 3-2: The 24V power which connects to proximity switch, photoelectric switch is disconnected or COM line is disconnected.

Solution 3-2: Check the +24 V and COM lines with multimeter.

Malfunciton 4, all proximity switches, photoelectric light switch, solenoid valve indicator does not light, and touch screen is not displayed.

Failure 4-1: 24 V fuse burned.

Solution 4-1: Check 24V fuse.

Failure 4-2: No input in 220V AC power, resulting in 24V DC no voltage output.

Solution 4-2: Check the 220V power circuit

Failure 4-3: No DC 24V voltage outputs in switching power or voltage is not enough.

Solution 4-3: Check, repair or replace the switch.

Failure 4-4: Lightning protection get damaged.

Solution 4-4: inspect and repair or replace the lightning protection.

Failure 4-5: The electrical control box 24V control circuit is disconnected.

Solution 4-5: Check the +24 V and COM lines.