PLC Communication and Network Cables

 PLC communication

In This chapter we discuss about Siemens (PLC communication, Serial communication , Industrial network and Network Cables ) devices overview.

Chapter -16





  • Communication is central to what a PLC does.
  • Therefore understanding communication concepts is critical to understanding PLC'S.

  • PLC'S communicate with many other devices and systems in various ways.
  • In some situations a PLC connects directly to another device.
  • Often however various components of an automation system including PLC'S are interconnected using Network Technologies.

Serial Communication

  • Serial communication is the most basic form of data communication used by PLC'S because it involves transmitting data one bit at a time on a signal line and receiving data in the same fashion on another signal line or in some cases the same line.
  • A PLC uses serial communication with a variety of devices such as personal computers, printers, RFID readers, and barcode scanners.
serial communication
  • Serial communication uses interface standards such as RS-232, RS-422, and RS- 485 that identify the signal lines available for communication.
RS-422
  • All three types of interfaces can be used for a point-to-point communication.
  • RS-422 and RS-485 can also be used for a multi-drop configuration with multiple devices connected on the same set of signal lines.
RS 232

  • Connecting a PLC to another device via an RS 232, RS 422, or RS 485 interface often requires a communication module. 
RS 485
  • For example the accompanying graphic shows S7-1200 communication modules used for serial communication.
S7-1200 communication modules



Industrial Networks


  • In most factories the need for rapid information flow is critical.
  • This often requires intelligent devices such as ( PLC'S, drives, computers, HMI'S and some actuators and sensors to be interconnected by one or more local area networks.
  • A LAN is a communication system designed for private use in a limited area.
  • LAN'S are used in office areas as well as in manufacturing environments however LAN'S used in industrial applications must be able to operate reliably in conditions that are unsuitable for office equipment.
  • Issues such as data rate, the number of devices to be connected, the reliability and noise immunity required compatibility with other network    and cost are examples of important industrial network considerations.
  • Another important characteristic that defines networks is the network topology.
  • The topology of a network is the pattern formed by network devices.
  • Examples of network Topologies include

Star, Tree, Linear, Ring, and Combined Topologies.


  • Some networks allow all of these topologies and other networks are more limited in the types of topologies available.
  • No single topology is best for all applications so careful consideration should be given when choosing the specific topology for a network or portion of a network.


Network Cables

  • A variety of cable types are used for industrial network communication.
  • Two types of cables used for Industrial Ethernet including PROFINET are shielded twisted pair cable and fiber optic cable.

  • Shielded twisted pair cable consists of twisted pairs of copper wires with a layer of braided wire between the outer plastic jacket and the inner conducting wires to provide protection from external sources of electrical noise.
  • Fiber-optic cable is recommended for use in applications with high levels of electrical noise where grounding problems exist or where electrical isolation is needed.
  • These cables are also used in open-air systems or where no electromagnetic radiation is permitted.

  • PROFIBUS networks also use various types of shielded twisted pair cables.
  •  AS-Interface networks  however use a two-wire cable that caries both data and power.

Wireless Communication
  • Wireless network devices send and Receive signals through the air.
  • Wireless networks are used where devices must be mobile or where it is too expensive or difficult to run cables.
  • For example the accompanying graphic shows a mobile panel that allows an operator or maintenance person to monitor a system without being tied to a control room.


  • Wireless networks are also used where the controlled equipment must be mobile such as with automated guided vehicle systems, overhead monorails, and cranes.
  • One of the most popular types of factory wireless networks is IWLAN, which stands for Industrial Wireless Local Area Network.
  • IWLAN uses devices with antennas to transmit and receive radio wave signals.
  • There are a variety of antenna types used with IWLAN.

 
  • This includes BQ9M radiating cables, one of which is shown in the foreground in the accompanying graphic.
  • RCoax cables are used as antennas from IWLAN access points.
  • Openings in the outer conductor of the cable provide a defined Signal strength along the entire length of the cable enabling reliable radio links in areas where conventional antenna technology is impractical.
  • For example this unique antenna design allows RCoax cable to be laid in the rails of an overhead monorail track where standard antenna technology is very costly to install and maintain.


Chapter 17 we will discuss about ( Profibus DP , Actuator Sensor Communication , Industrial Ethernet , Profinet , Profinet Device , Profinet Profiles ) Topics.

SIEMENS PLC Class for Beginners

Please Share this article, with your friends and colleagues

Comments

Post a Comment

Popular posts from this blog

Danfoss VLT micro drive FC 51 Name Plate

Image
In this Article, we are going to discuss about what specifications are mentioned on the Danfoss VLT micro drive FC 51 name plate sticker. Welcome to controls and systems blog page, The nameplate sticker is located on the top of each VFD drives and shows the ratings, serial number, warnings catalog number, and other relevant data for each unit. This nameplate sticker is mostly the same in the VLT model VFD drives, with only a few changes in the some VLT model VFD drives. 1 st ROW: ( TYPE CODE ) Position 1 - 3 [FC]-  is Product group, Possible choice is: Frequency converters, Position 4 - 6 [051]  is Series and product type, Possible choice is: Micro Drive, Position 7 - 10  [P]  is Power size, Possible choice is: 0.18 to 22 kilo watt. Position 11 - 12  [S2]  is Mains voltage, Possible choice is: S2 that means Single phase 200 to 240 Volt AC, T2 that means 3-phase, 200 to 240 Volt AC, T4 that means 3-phase, 380 to 480 Volt AC, Position 13 - 15  [E20]  i
Read More »

QElectro Tech Software Overview

Image
  In This Article we are going to see QElectro Tech Software Overview... QElectro Tech QElectroTech QElectroTech is a free software to create electric diagrams. QElectroTech or QET in short is currently available in version 0.80. This Software is Very Effective and Very Useful for Electronic, Electrical, and Instrumentation Department Engineers. Compare to other Diagram Software’s ‘exe’ Setup file of QElectro Tech Software Size is Too Low. There are Lot of Electrical, Electronic and Instrumentation Symbols and elements are in this QElectro Tech software. The Software of Table of Contents is following of ( Basics , Interface , Preferences , Project , Folio , Element , Conductor , Schema , Drawing , Reports , Export and print , Annex etc..) QElectro Tech Documentation 1 QElectro Tech Documentation 2 The QElectro Tech Software contains many collections (Electrical , Logic , Hydraulic , Pneumatic and Energy symbols and Elements) also user can create they own symbols. Anyone can Access
Read More »

SIEMENS V20 VFD DRIVE MAIN PARAMETERS LIST

Image
   SIEMENS V20 VFD DRIVE MAIN PARAMETERS LIST This Parameter Setting is Suitable for (  Manual ON/OFF Mode , Auto Frequency Mode , Pot meter Varying Mode ) its Deepened on (0-10)v Dc signal. SIEMENS V20 VFD DRIVE MAIN PARAMETERS LIST   Parameter Setting Description P0003 1 Standard: Allows access into most frequently used parameters P0010 30 Factory setting P0970 1 Resets all parameters P0010 1 Quick commissioning P0100 0 Europe [kW], motor base frequency is 50 Hz P0301 22 Rated motor KW [KW] P0304 415 Rated motor voltage [V] P0305 35 Rated motor current [A] P0307 22 Rated motor power P0308 0.82 Rated motor cosĪ† P0310
Read More »

SIEMENS V20 VFD DRIVE FAULTS CODE LIST PART-1

Image
In this article  we are going to discuss about siemens v20 vfd drive fault Cause and Remedy for this  fault codes ( F1, F2 , F3 , F4 , F5 , F6 , F11 , F12 , F20 , F35 )   SIEMENS V20 DRIVE F1  -  FAULT:    Overcurrent CAUSE : Motor power (P0307) does not correspond to the inverter power (r0206). Motor lead short circuit Earth faults r0949 = 0: Hardware reported r0949 = 1: Software reported r0949 = 22: Hardware reported REMEDY : Check the following: Motor power (P0307) must correspond to inverter power (r0206). Cable length limits must not be exceeded. Motor cable and motor must have no short-circuits or earth faults. Motor parameters must match the motor in use. Value of stator resistance (P0350) must be  correct. Motor must not be obstructed or overloaded. Increase ramp-up time (P1120) Reduce starting boost level (P1312) F2  -  FAULT:  Overvoltage CAUSE : Main supply voltage too high Motor is in regenerative mode r0949 = 0: Hardware reported r0949 = 1 or 2: Software reported REMEDY
Read More »

SIEMENS VFD FAULTS CODE LIST PART-2

Image
In this article  we are going to discuss about siemens v20 vfd drive fault Cause and Remedy for this fault codes ( F41, F51 , F52 , F60 , F61 , F62 , F63 , F64 , F71 , F72 ) Fault Vfd Drive F41   -  FAULT: Motor data identification  failure Motor CAUSE : Motor data identification failed. r0949 = 0: No load applied r0949 = 1: Current limit level reached during identification. r0949 = 2: Identified stator resistance less than 0.1% or greater than 100%. r0949 = 30: Current controller at voltage limit r0949 = 40: Inconsistency of identified dataset, at least one identification failed Percentage values based on the impedance Zb = Vmot,nom / sqrt(3) /  Imot,nom REMEDY : Check the following: r0949 = 0: is the motor connected to the inverter? r0949 = 1 - 49: are the motor data in P0304 - P0311 correct? Check what type of motor wiring is required (star, delta). F51 -  FAULT:   Parameter EEPROM fault EEPROM CAUSE : Read or write failure while access to  EEPROM.  The EEPROM being f
Read More »