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SLC 500 COMMUNICATIONS. Requirements for Industrial Networks. An industrial communication link Capable of supporting real-time control High data integrity High noise immunity High reliability in harsh environments Suitable for large installations. Local Area Network - Applications.
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SLC 500 COMMUNICATIONS
Requirements for Industrial Networks • An industrial communication link • Capable of supporting real-time control • High data integrity • High noise immunity • High reliability in harsh environments • Suitable for large installations
Local Area Network - Applications • Centralized Data Monitering and Acquisition • Manufacturing • SCADA • MMI • Distributed Control • Communication between programmable controllers • Upload to a programmer or host computer from any PLC • Download from a programmer or host computer to any PLC • Read/write I/O values, registers of any PLC • Monitoring of PLC status and control of PLC operation
SLC SLC SLC SLC Network Topologies • Daisy-Chain • Each device has two sections of cable tied together • Each end has termination (resistor/capacitor) Examples DH+ DH-485 Remote I/O Beldon #9463 cable
PLC PLC PLC Network Topologies • Star • All devices physically connected at one point Example Ethernet PLC
Trunk Line Drop Line Drop Line Drop Line Drop Line SLC SLC SLC SLC Network Topologies • Trunk-Line / Drop-Line • Trunk line very long - run through plant • Drop lines very short • Drops connected to trunk with Y-adapters Examples Data Highway (DH) Devicenet DH+ can be
TOKEN SLC SLC SLC SLC Network Access Methods • Token Passing: • Each node can talk on the network when it has the token • After done talking, the node will “Pass the token” to the next node • Multi-master network • Eliminates data collisions # 1 # 3 # 4 # 2
Network Controller (Master) Network Access Methods • Master / Slave: • Master talks to one slave at a time • The slave can only talk if the master asks it for some information • Polling network • Eliminates data collision • Single master network Request ? Reply ! # 1 # 4 # 2 # 3 SLC (Slave) SLC (Slave) SLC (Slave) SLC (Slave)
Networks - How to Decide on One? • Maximum number of devices • How many nodes are required for the application? • How many nodes should be reserved for future expansion? • Maximum network length • Usually specified as the physical cable distance from the first node to the last node on the network • Drop length is the length of cable from the main cable to the node • Device supported • Programmable controllers • Programming devices • Operator Interfaces • Other Computers - PCs, Workstations, Minis, Mainframes... • Response time • Application interface
A-B Communication Network Terms What the hell do all these mean? RS-232 RS-422 RS-485 DH-485 REMOTE I/O DF1 DH+
A-B Communication Network Terms } RS-232 Electrical Connections RS-422 RS-485 } DH-485 REMOTE I/O Protocols (languages) DF1 DH+ Must have matching electrical connections and protocols for two computers to communicate.
Communications - Like a Phone Call... Electrical Connection is made when person answers phone
COMMS Communications - Like a Phone Call... Electrical Connection is made when person answers phone ENGLISH FRENCH
COMMS Communications - Like a Phone Call... Electrical Connection is made when person answers phone Communication when connection make AND both people speak the same language ENGLISH FRENCH COMMS ENGLISH ENGLISH
Networks: DH-485 and DH+ • Network Communications • Program support and monitering • Supervisory control for distributed hierarchy • Operator interface for monitoring and control
DH-485 Characteristics • DH-485 Multi-drop link • Daisy chain configuration • Token passing system • 9.6 or 19.2 Kbaud data rate • Connect up to 32 devices on network • Up to 4000 cable feet (1200 meters) of network lenght
Send/Recv messages from other SLC 500s Multi-master token-passing ring; 32 nodes 5/02, 5/03 + 5/04 can initiate communications to other processors 5/03 can using Channel 0, Channel 1, or both 5/04 can using Channel 0 only Fixed and 5/01 respond only Initiate comms. with MESSAGE instruction in ladder logic NO ladder programming necessary to respond to a message from another processor DH485 Peer-to-peer Comms.
ALLEN-BRADLEY DTAM Plus RUN ALARM PIC AIC+ SLC 5/04 Link Coupler Link Coupler Link Coupler Link Coupler SLC 500 Fixed SLC 5/03 SLC 5/02 SLC 5/01 Typical DH-485 Network
Peer-to-Peer Communication Utilizes Tolken Passing 64 nodes maximum Remote Programming of SLC 500’S, PLC-2, PLC-3, and PLC-5 Direct Connections to 5/04,PLC-5, Panelview, and Industrial Terminals 57.6, 115.2, OR 230Kbaud data rate Pub # 1770-6.5.16 DH/DH-485/DH+ Ref Manual Robust Industrial Network DH+ Characteristics
DH+ Communications RSLogix 500 Software AI 500 Software 6200/AI Software 57.6Kbaud: 10,000 feet 115.2Kbaud: 5,000 feet 230.4Kbaud: 2,500 feet DH+ Other Processors PLC-2, PLC-3 PLC-5/250 PLC-5 SLC-5/04
SLC 5/04 RSLogix 500 Software PLC-5 PLC-5 DH+ DH+ DH-485 Network #2 DH-485 Network #1 Link Coupler Link Coupler Link Coupler Link Coupler SLC 5/01 SLC 5/02 SLC 5/03 SLC 5/03 DH+ to DH-485 Interface • Interface through a 1785-KA5 • Translate DH-485 <-> DH+ • Allows PLC5s and SLCs to communicate
RS-232 Communications • SLC-5/03 and 5/04 Support: • Full-Duplex (Point-to-Point) • Half- Duplex • ASCII • Modem Communication
RS-232: DF1 Full-Duplex • AKA: DF1 Point-to-Point • Simultaneous transmission between two devices in both directions • - Programming Port • - Peer Messaging
RS-232: DF1 Half-Duplex • Mulit-Drop, Single Master, Multiple Slave • Slaves are Polled for Response from the Master • Supports up to 255 Slave Devices • Slaves: Any SLC Processor • Master: PLC-5, SLC-5/03, 5/04, CV
Point-to-point communications RS-232 Using Channel 0 w/ DF1 Full-Duplex 5/03 + 5/04 Serial Port RSLogix 500 Programming Software Modem Modem SLC 5/03 or 5/04
Master/Slave communications Polled Network Using Channel 0 w/ DF1 Half-duplex Master or Slave 5/03 + 5/04 Serial Port Master DF1 Master (RSView) Modem Slave(s) Modem Modem Modem SLC 5/03 SLC 5/04 RSLogix 500 Programming Software
5/03 and 5/04 Direct connection to devices such as barcode decoders and printers Eliminates requirement of BASIC module for this task SLC 5/03 CPU RUN FORCE FLT DH485 BATT RS232 RUN REM PROG ASCII Communications
Converts electrical signals RS-485 to RS-232 Translates protocols DH-485 to DF1 Configured thru the backplane (Series B) DH-485 / RS-232 ACT FAULT 485 BA LOW CFG H/D F/D DF1 1747-KE Module RS-232 Config RS-232 DF1 DH-485 RS-485
RS-485/DH-485 to RS-232C/DF1 interface module Acts as a BRIDGE between two different networks or types of communication Called a Bridge module (1) DH-485 port (2) Serial ports (RS-232, 422, 485) Allows remote communications to SLC 500 systems DH-485 / RS-232 ACT FAULT 485 BA LOW CFG H/D F/D DF1 1747-KE Module
• Point-to-Point configuration using full duplex DF1 communications • Remote communications from the programming software to a remote network of SLC 500 processors. • RSLogix 500 acts as if it were directly on the DH-485 network Typical KE Configurations RSLogix 500 Modem Modem SLC 500 DH-485 Isolated Link Coupler 1747-AIC SLC 5/01
SLC 500 with KE Typical KE Configurations Master • Master/Slave communications • Polled Network • Using Channel 0 w/ DF1 Half-duplex Slave DF1 Master (RSView) Modem Slave(s) Modem Modem Modem Modem SLC 5/02 with KE SLC 5/01 with KE RSLogix 500 Programming Software
MSG ( EN ) Read/Write Message Type Peer-To-Peer ( DN ) Read/Write Read ( ER ) Target Device 500CPU Local/Remote Local Control Block ? Control Block Length 14 Setup Screen Peer-to-Peer Communications Read/Write: Read - local processor is receiving data Write - local processor is sending data Target Device: 500CPU if target is another SLC Processor 485CIF if target is a non-SLC device on the network PLC5 if target device accepts PLC-5 commands Local/Remote: Local - the message is to be communicated via a local network Remote - the message is to be communicated to a remote device on another network through a bridge Control Block: Contains - target node address, local file address, target file address, status bits Control Block Length: Fixed at 14 elements Setup Screen: Advanced setup parameters EN: enable bit - set when rung is true DN: done bit - message successfully transmitted ER: error bit - transmission failed