FAQ/SAFETY NOTES
Technical Support
FAQ
  • Q How to install NPN/PNP transducer on PLC?
    A
    1.General PLC (Programmable Logic Computer) could select input type NPN or PNP, by connects S/S to 24V or 0V respectively.
    ■ NPN input:
    S/S connects to 24V.
    ■ PNP input:
    S/S connects to 0V.




    2.Considering PLC power supply ability, please apply external power to sensors rather than internal power of PLC.



    Attention:Please notice that GND of external power shall be connected to GND of PLC.
  • Q MODBUS wiring?
    A

    Modbus is one kind of protocols that machine can transfer data through this method. Generally speaking, MODBUS is to machines what language is to human beings.

    Communication protocol is software level protocol, and different devices exchange data through the same protocol.

    Then machine needs physical port to transfer data, such as EIA 485(RS485)、EIA422(RS422)、EIA232(RS232) or RJ45 Ethernet.

    Attention:Device with RS485 port does not mean it must support Modbus Protocol. Please contact Device provider for more information.





    1.
    RS485 sign

    RS485 2 wires
    Receive D
    RS485 
    RX
    TX
    RDA
    SDA
    RDA
    SDA
    A
    Transmit D+
    RS485+
    RX+
    TX+
    RDB
    SDB
    RDB+
    SDB+
    B


    2.Connection diagram

            


    3.Examples:KP75口-02/04 Circuit wiring diagrams
    MODBUS接線方式為B+連接設備端上D+(RS485+),A-連接設備端上的D-(RS485-)。


    4.Make sure the principle of connection is correctly when do wiring, and do not use T type wiring method, star type wiring method or any other wiring method for convenience.



    5.Keep away from high noise source when wiring. Do not use the same groove as the power wire uses in the distribution box. Externally, keep as far away as possible from devices which have electric magnetic radiation.
    The transfer wire need to use shielded twisted par wire. Normal twisted pair wire can be used when conducting short distance communication in low noise environment to reduce cost. But in high noise environment, long distance communication or in case of high communication quality is required, the dedicated transfer wire for RS-485 is recommended. It may make higher budget, but the communication quality will be improved magnificently.




    6.Terminal resistances must be parallel connected to the two terminal points of the whole communication circuit. For the twisted pair wire used by RS-485 interface, the terminal resistances should choose 120 Q 1/2 W ones.

  • Q Final check before transmitting data
    A

    1. Check whether the communication software is working properly, including whether the communication parameters (such as ID, baud rate, check bit, delay, time-out setting) are correctly.
    2. Reduce environmental interferences.
    3. Re-wire the transfer wire, and avoid noise source.
    • ID:ID can only be identical.
    • Baud、Parity Check Bit:Ever part of system setting should be same.
    • Delay Time:Short delay time interval may cause data lose.
    • Time out:1000~500ms are recommended, depending on devices.

    If everything on the system is done correctly and communications still do not work, please contact PLC provider for more PLC communication setting details.

  • Q LED on magnetic switch does not work
    A

    Check power supply type (AC or DC) of product

    ■  AC-powered product
        Switch works:LED is out of order. Please send back for examination.
        Switch doesn't work:Please refer《The Malfunction of Magnetic Switch》

    ■  DC-powered product
         Switch works:Check the polarity of wiring.
          — Wrong:Please correct it. Please refer to the figure below
          — Correct:Please send back for examination.
         Switch doesn't work:Please refer《The Malfunction of Magnetic Switch》

      
  • Q The malfunction of magnetic switch
    A

    Check wiring

    ■  Correct:Remove magnetic switch from cylinder, and use a magnet to test the switch.
    1. Switch works:the magnetic field of the magnet inside the cylinder is not enough or the sensitivity of magnetic switch is too weak. Please contact our RD  department.
    2. Switch doesn't work:Please send back for examination.

    ■  Wrong:Please correct it.

      
  • Q Contact point is unbreakable
    A

    Check whether the magnetic switch is overloaded.

    ■  No:Check the wire distance between the magnetic switch and the load is more than 10M or not.
    1. Over 10M:Add an inductor (About 1000uH) to eliminate to capacitor impulse caused by long wiring.
    2. Below 10MPlease send back for examination.

    ■  Yes:
    1. Exchange magnetic switch with larger rated operating voltage, current, and contact rating.
    2. Use relay or PLC to drive the load indirectly.
  • Q The LED flashes and turns off
    A

    Check whether the loading current is too high.

    ■  Yes:
    1. Exchange magnetic switch with larger rated operating voltage, current, and contact rating. 《Please refer to the figure below》
    2. Use relay or PLC to drive the load indirectly.
    ■  No:Please send back for examination.

  • Q Magnetic switch operates twice continuously
    A
    Since the magnetic field of magnet is too strong or the sensitivity of magnetic switch is too high.
    Please contact to our RD department.