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Programmed Maintenance of (Ethernet, DH+, DeviceNet & ControlNet) Networks


  • All maintenance work should be carried out by a qualified Control & Instrumentation personnel familiar with the construction, operation and hazards involved with control equipment.
  • Maintenance should be performed with the control out of operation and disconnected where necessary. If maintenance must be performed while the control is energised, the safety related practices must be followed. Refer to NFPA 70E work practices.
  • Care must be taken when dealing with Mains Powered equipment.
  • All Personnel Safety Equipment required must be used (e.g. safety glasses).


Required to accomplish this task are as follows:

  • Standard Instrument Tool Kit
  • Small Torch
  • Standard Industrial Network test kit and Industrial Toughbook.


Required to accomplish this task are as follows:

  • Cleaning Supplies. (Chux cloth)
  • Length of 1/4” Poly Line.
  • Clean dry PC Air Filter.
  • 3 1/2” Floppy Drive Cleaning Kit.
  • CD-ROM and ZIP Drive Cleaning Kit.


This procedure is generated for a monthly Programmed Maintenance of all NETWORKS components. The procedure covers hardware as well as software checks.


  • Care should be taken when servicing electrostatic sensitive components. Refer to manufacturer recommendations.
  • Grounding & Insulation of the equipment should be checked to assure its integrity.
  • Ventilation passage should be kept open. Certain hazardous materials removed, as part of maintenance or repair procedure must be disposed as per Federal Regulations.
  • Lithium batteries are frequently used for memory back up in control equipment. The Lithium batteries removed must be disposed as per supplier’s instructions.


  • Inform area supervisor before commencing the work. Obtain a SWC before starting.
  • Enclosures should be inspected for deterioration and accumulation of dust and dirt.
  • Accumulation of dust and dirt on all parts should be removed according to the manufacturer’s instructions.
  • Care must be taken to avoid damaging any delicate components and to avoid displacing dust, dirt in a way that permits it to enter or settle into parts of the control equipment.

A. ETHERNET NETWOKS. The network is based on Ethernet IEEE 802.3 & IEEE 803.2 TCP/IP LAN standards at 100MBPS.


  1) Open the rear doors of the control desk where the network connections are.
  2) Do not cause any interruption to AC power supply. Be careful not to touch the power switches or reset them accidentally.
  3) Check the fibre optics cables and physical connections for any damage or deterioration.
  4) Check the Fibre Optics Patch Panel physical connections and clean any dust accumulation.
  5) Check Hubs Power LED is ON.
  6) Check Hubs Activity LED is ON.
  7) Check Hubs Collision LED is OFF.

B. DH+ NETWORKS. The Data Highway Plus (DH+) network is a LAN designed to support remote programming and monitoring of Allen Bradley PLC systems in the plant.


  1) Check the physical DH+ connection between PLC5 and KA5 card for deterioration and loose connection.
  2) Ensure that PLC-5 and KA5 card are indicating normal operation LEDs.
  3) Check if the right type of cabling system is used.
  4) Check that each Node has a unique link Ids.

C. DEVICENET NETWORKS. DeviceNet is a communication link which connects industrial devices (e.g. limit switches, sensors, valves, panel displays…etc.) into a network.


  1) Make sure that the physical cable connections are secured tightly.
  2) Make sure that the Terminating Resistors are properly secured at both ends of the network trunk line. Normally TRs are 121 ohm, 1/4 watt.
  3) Check the system application functions as expected.
  4) Check the Module Status Indicator on the scanner is Solid Green.
  5) Check the Network Status Indicator on the scanner is Solid Green.
  6) Check the Address/Code Indicator on the scanner displays the scanner Node Number.
  7) Check the Network LED on all slave devices on the system is Solid Green.
  8) Check the RS-232 Status Indicator on RS-232 Interface Module (1770-KFD) is Flickering Green.
  9) Check the Module Status indicator on RS-232 Interface Module (1770-KFD) is Solid Green.

D. CONTROLNET NETWORKS. ControlNet is a communication link, which connects all Allen-Bradley PLCs and I/Os into a Network.


  1) Check the physical connections are secured tightly.
  2) Check the Terminating Resistors are properly secured at both network ends. TRs normally 75 ohms.
  3) Check the normal operation of PLC.
  4) Check the system application functions as expected.



Comments (1)Add Comment
written by kim, June 06, 2013
buhi pa diay ni nga site gaw?

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