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PLC FAULT CHECK MAINTENANCE


Judge the Error through the Indicator at the Front Panel
When error occurred for the DVP PLC, please check:


POWER LED


There is a “POWER” LED at the front of the MPU. When the MPU is powered On, the green LED light will be on. If the indicator is not on when the MPU is powered up and with the input power being normal, it is an indication that the PLC is out of order. Please have this machine replaced or have it repaired at a dealer near you.

RUN LED


Identify the status of the PLC. When the PLC is in operation, this light will be on, and users could thus useHPP or the ladder diagram to edit program and give commands to make the PLC “RUN” or “STOP”.

ERROR LED


1. If illegitimate program is input to the MPU, or that the commands and devices of the program exceed the allowable range, the indicator will thus be blinking. In this case, the user should inquire about the errorcode from the special data register D1004 in the MPU and look it up in the Error Code Table. After the error is found and the program is revised, send the revised version to the MPU.

2. If the PLC is unable to perform function, and the LED is blinking swiftly, it indicates that 24VDC power does not supply sufficient power. Please check whether the power supply of 24VDC is normal or not.

3. When the ERROR LED is on (not blinking), it is an indication that the execution time of the program circuit has exceeded the preset time-out limit (setting of D1000). To check the program circuit or use theWDT command to improve the error status. Once program modification is completed, user can re-download the program of PLC and the ERROR LED will be off. If the ERROR LED is still keep on,please turn off the power and check if there’s any noise or any conductive invader inside the PLC.“Input” LED The On/Off signals of the input point could be displayed through the “Input” LED, or monitor the status of the input point through the device HPP monitoring function. Once the motion of the input point is valid, the LED is on. Therefore, if errors are detected via using HPP, the LED and the input signal circuits then are used to check whether the status is normal. Especially when the electronic switch of great electric leakage is utilized, the input point is usually witnessed with unexpected motions.

Output LED 


The “Output” LED is designed mainly for display the On/Off status of the output signals. When the “Output” LED is On or Off and that the loading is of an opposite motion, the following conditions should be attended to:

1. The output contact might be melted down and blocked up due to overload or load in short-circuit,   defect happened consequently under this situation.

2. If the output contact is function as undesired, be sure to check the output wiring circuit and whether the screw is tightened or not.

PLC Error Code Table

PLC Periodic Inspection

 Since the DVP series PLC does not utilize disposable components, there is thus no need to replace most of the components. However, if the output relay turns on/off frequently, or drive the large load current too often, life of the output contact will thus be decreased. Under a condition like this, periodic inspection is then needed to ensure if the contact is of the “Permanently Open” status or of the short-circuit status. Moreover, the following precautions should be noted:

1. Do not mount the DVP under direct sunlight or near any heat-radiation objects.

2. Do not install the DVP-PLC in places subject to high temperature, high humidity, excessive vibration,corrosive gasses, liquids, airborne dust and metallic particles.

3. Check periodically whether the wiring and terminals are tightened and conducted properly

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