Allen-Bradley Data Highway II PLC-2 User Manual Download Page 99

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Programming the Local Host

Chapter 5

542

Therefore, when using the write bit command, address only bits within a
byte which are set aside exclusively for control by these commands.

Note that this byte restriction for write bit commands does not apply to
any but the PLC-2 family processors.

After you have generated a program at each host to communicate with the
other nodes, you can begin to start up and operate the Data Highway II
network.

Chapter Summary

Summary of Contents for Data Highway II PLC-2

Page 1: ...User Manual Data Highway II PLC 2 Family Interface Cat No 1779 KP2 KP2R Allen Bradley...

Page 2: ...nterfaces 2 5 Data Highway II Network 2 5 Media Access Method 2 9 Bridges to Other Data Highway II Links 2 10 Command Reply 2 10 Message Priority 2 14 Redundant Cabling 2 17 A Second Link 2 18 Chapter...

Page 3: ...bution 4 17 Chapter Summary 4 18 Programming the Local Host 5 1 Chapter Objectives 5 1 Communication Zone 5 1 Status Words 5 16 Initiating and Monitoring Commands 5 23 Memory Access Limitations 5 40 C...

Page 4: ...e appropriate manual for the controller you are using Consult our Publication Index Publication 499 for a list of our publications The redundant PLC 2 DHII interface has all of the functions of the PL...

Page 5: ...Link Cabling Hardware Installing taps droplines and trunklines for Data Highway II link 4 Installing PLC 2 DHII Interface Installing PLC 2 DHII interface and connecting it to a PLC 2 family processor...

Page 6: ...o 1779 JP2 One Media Access Controller Board Cat No 1779 JMA A redundant PLC 2 DHII interface has a redundant media access controller board Cat No 1779 JMAR instead of a Media Access Controller board...

Page 7: ...Introducing the PLC 2 DHII Interface Chapter 2 2 2 Figure 2 1 PLC 2 DHII Interface with Removable Frame Separated from Stationary Frame Stationary Frame Removable Frame...

Page 8: ...a PLC 2 family processor host processor and other nodes of a Data Highway II link Figure 2 3 The power supply board converts AC power to DC power that the PLC 2 host board and MAC board use The power...

Page 9: ...h connectors on its front surface Figure 2 4 The PROCESSOR connector provides cable connection to the PLC 2 family processor At the PLC 2 family processor the cable mates with the connector provided f...

Page 10: ...evice DHII Interface Cat No 1779 KFMR PLC 2 DHII Interface Cat No 1779 KP2 Redundant PLC 2 DHII Interface Cat No 1779 KP2R PLC 3 DHII Interface Cat No 1779 KP3 Redundant PLC 3 DHII Interface Cat No 17...

Page 11: ...ess to the Data Highway II link Two nodes for such stations are shown in Figure 2 5 One node comprises a 1779 KFM interface to a computer through an RS 422 449 link limited to 4 000 cable feet Another...

Page 12: ...L interface in later chapters Figure 2 5 A Data Highway II Network with Two Data Highway II Links PLC 3 Processor PLC 2 15 Processor PLC 2 30 Processor 1779 KP3 Interface 1779 KP2 Interface 1779 KP2 I...

Page 13: ...79 KFL interface A dumb terminal is shown communicating with other nodes through an RS 232 C link and a 1779 KFL interface Each 1779 KFL interface has two channels for connection to two host devices a...

Page 14: ...p to 4 100 cable feet Refer to Chapter 3 for detailed information on planning cable lengths The Data Highway II link provides carrier band signaling through frequency shift keying The carrier frequenc...

Page 15: ...n token which it passes around to its nodes For example in Figure 2 5 the computer could send a message to the PLC 3 processor at the same time that the PLC 2 30 processor is sending a message to the...

Page 16: ...ves a command from another node to read an immediate access block it reads the specified block of data from its buffer and immediately transmits the reply message without waiting to receive the token...

Page 17: ...mmand to write with reply When the remote node interface receives the token it transmits a reply message to indicate whether it was able to successfully write into the host s memory When the local nod...

Page 18: ...ster encoding and CRC 16 error checking to help ensure data integrity before the interface writes data into its host s memory A write verified command may provide added security in applications where...

Page 19: ...side for supervisory messages so that they get to their destination regardless of the number of time critical messages to be transmitted You can send time critical messages to other nodes of the same...

Page 20: ...mands Read Immediate Access Block Update Immediate Access Block Accepted Commands The PLC 2 DHII interface can accept commands from remote nodes The interface will interpret the command check switches...

Page 21: ...monitor user programs from other Data Highway II nodes Remote Command Control Third Party The PLC 2 DHII interface has a special facility to allow other nodes to program them just as if a command had...

Page 22: ...sly monitors the quality of the signal it receives from each cabling system As a node interface receives a message it always accepts the message from the cabling system providing the better signal qua...

Page 23: ...10 Data Highway Link and a Data Highway II Link for a PLC 2 Family Processor 1771 KA2 Module 1779 KP2 Interface PLC 2 30 Processor 1771 KA Module Processor PLC 2 05 PLC 2 20 Processor Interface 1779...

Page 24: ...Highway II link you need the following cabling hardware items Part A B Catalog Number Manufacturer Information RG 11 Type Coaxial Cable None Times Wire Cable AA 5066 Astro Wire Cable 20 111A Alpha 51...

Page 25: ...sulation Insulating Jacket Local Tap Each node of a Data Highway II link requires a local tap Each local tap has two trunkline jacks a dropline jack and a cap for covering the dropline jack when you d...

Page 26: ...ocal Tap Trunkline Jack Dropline Jack Cap Tap Sleeve Pin Body Cable Plugs 2 Straight Plug Right Angle Plug Dropline Cable Assembly Crimping Tool You will need the crimping tool for fastening the cable...

Page 27: ...f the link You require a tap for each node of the link Also if you plan to add nodes later provide a tap for each future node during initial installation This will avoid the disruption of adding taps...

Page 28: ...Configuration of a Data Highway II Link Trunkline Terminator Dropline Node Interface Tap Terminator Figure 3 6 Relationship between Trunkline Length and Number of Nodes with Local Taps Length of 2K 2...

Page 29: ...ability of the link Plan your trunkline cable routing so that the cable will have no sharper bend than a minimum 6 inch bend radius Figure 3 7 Figure 3 7 Trunkline Cable Showing Minimum Bend Radius 6...

Page 30: ...not violate the 6 inch minimum bend radius Figure 3 9 Tap Mounting Dimensions Use No 5 mounting bolts 2 Places 1 0 in 25 mm 1 5 in 38 mm 2 1 in 54 mm 3 1 in 79 mm 3 5 in 89 mm 0 2 in 6 mm Clearance De...

Page 31: ...rthermore you can only mount the tap on the side of the chassis if the PLC 3 interface module is at the end of the chassis Figure 3 10 shows an example of a tap mounted below a node interface The trun...

Page 32: ...cable routing recommendations for protecting the coaxial cable from electrical interference If the cable must cross power feed lines it should do so only at right angles Keep the cable at least 1 foot...

Page 33: ...the conduit by attaching it to the steel structure of the building Do not let the conduit touch the tap or the plug on the cable Third conduit should only contain serial communication cables Cables wi...

Page 34: ...tween the taps of two neighboring nodes on the trunkline Figure 3 5 Three major tasks are required in constructing the trunkline Cutting the cable into segments of appropriate length Attaching the plu...

Page 35: ...2 inches of insulation from the end of the cable segment exposing the inner conductor 5 Push the plug pin as far as possible onto the center conductor of the cable 6 Use the crimping tool to crimp the...

Page 36: ...I Link Cabling Hardware Chapter 3 3 13 Figure 3 13 Attaching the Cable Plugs Coaxial Cable 0 7 in 0 3 in 0 2 in Plug Sleeve Plug Pin Braid Plug Body Crimped Sleeve Steps 1 through 4 Steps 5 and 6 Step...

Page 37: ...3 14 Figure 3 14 Terminator and Trunkline Segment Connected to a Tap at One End of the Link Terminator Trunkline Segment Tap Dropline At each tap other than at the end of the link plug the two trunkli...

Page 38: ...e interface out to the switch setting position before connecting the tap to the node interface This is the only way to be sure that the dropline will have enough slack in the switch setting position R...

Page 39: ...3 16 Connecting the Dropline from the Node Interface to the Tap Cap and Chain must not touch a conductive surface Tap Node Interface Dropline Once you have installed the Data Highway II link cabling...

Page 40: ...mmediately below any chassis PLC 2 DHII Interface processor chassis I O chassis power supply The failure rate of the semiconductor devices may increase significantly if the temperature is raised above...

Page 41: ...inches minimum vertical separation between chassis and to top and bottom of the enclosure with no chassis mounted above the 60oC air temperature level Figure 4 1 Provide minimum horizontal separation...

Page 42: ...mum Spacing for Necessary Air Flow for Cooling 4 4 4 4 6 6 1 6 4 6 6 6 1 1 The temperature of the air must not excceed 60 0 C 140 F at any point immediately below any chassis This may limit how high c...

Page 43: ...anel start the mounting bolt into the bottom hole You can then hold the interface in place resting it on the bottom bolt while you start the top mounting bolts Figure 4 2 Mounting Dimensions 6 5 in 16...

Page 44: ...rs Select a number from 010 through 077 or 110 through 376 Give each node of the link a unique link address The token will pass from node to node by order of link address Figure 4 3 Link Address MSD L...

Page 45: ...O N F F S4 4 3 2 1 1 2 3 4 O O N F F 1 2 O N F F 1 2 3 4 O O N F F 1 2 Reserved Reserved Reserved Reserved COMMUNICATION PARAMETERS O The switches are in four switch assemblies In this publication we...

Page 46: ...change network parameters stored on the interface for this node ON The interface accepts commands to change network parameters stored on the interface for this node Accept Third Party Requests The acc...

Page 47: ...the Ground Post on the Removable Frame 115V AC 230V AC L1 L2 N GND INTERNALLY SWITCH SELECTABLE Green Grounding Conductor 2 While holding the removable frame at the top and bottom lift in up an inch...

Page 48: ...or to a mini processor module PROGRAM INTERFACE connector to a second interface or communication module 1771 CO 3 4 feet 1 m PROCESSOR connector to a mini processor module PROGRAM INTERFACE connector...

Page 49: ...771 CN or 1771 CO cable for connection to a Mini PLC 2 Mini PLC 2 05 or Mini PLC 2 15 processor Use a 1771 CR cable for connection to a PLC 2 20 or PLC 2 30 processor Figure 4 7 Connection to the PLC...

Page 50: ...nector on the Industrial Terminal Figure 4 8 With this connection you cannot use tape cassette functions through the Industrial Terminal If you use two interfaces with the same processor Figure 4 10 y...

Page 51: ...RG with the processor connect a 1771 CN CO or CR cable from the PROGRAM INTERFACE connector on the interface to the PROCESSOR connector on the 1770 RG module Figure 4 9 Figure 4 9 Connection to a 1770...

Page 52: ...ion to a Second PLC 2 DHII Interface PLC Processor Tap Tap Interconnect Cable cat no 1771 CN 1 5 ft cat no 1771 CO 3 5 ft cat no 1771 CR 10 ft 1771 T3 Series B Rev F Industrial Terminal First Interfac...

Page 53: ...nnector on the second To Tap Pull the removable frame out to the switch setting position before connecting to the tap This is the only way to be sure that the dropline will have enough slack in the sw...

Page 54: ...V of the AC power source 3 Push the removable frame back to the operating position 4 Tighten the four thumbscrews on the front of the interface The thumbscrews must be tight to ensure that AC power is...

Page 55: ...al to the low side of the transformer supplying the AC power Figure 4 13 8 Connect the L1 terminal to the high side of the transformer supplying the AC power Figure 4 13 9 Install the supplied termina...

Page 56: ...nal of the power supply The power consumed by the PLC 2 DHII interface is 50W Multiply the power requirements of the Allen Bradley power supplies by 3 and add all other power requirements input circui...

Page 57: ...trical noise generators an isolation transformer can provide further suppression of electromagnetic interference from other equipment In applications where the AC power source is especially soft and s...

Page 58: ...can be transmitted to another PLC processor or to a computer and used by the other node to control its own part of an operation The communication zone is a set of rungs with a well defined beginning...

Page 59: ...22 G 024 G 027 07 032 11 017 XX 120 00 120 01 120 02 120 03 120 04 120 05 120 06 120 07 120 10 120 11 135 11 U 027 07 Read Write Block Header Rung Memory Access Rung Write Bit Delimiter Rung START Pro...

Page 60: ...he GET instructions Header Delimiter Rungs A minimum communication zone consists of a header rung and a delimiter rung The delimiter rung defines the end of the communication zone This rung must be ex...

Page 61: ...sion preceding Figure 5 12 The timeout preset code gives a programmed timeout interval for command completion Based on the three digit value entered for the address in these GET instructions the PLC 2...

Page 62: ...ed of one or more memory access branches as shown in Figure 5 3 In the memory access branch format a branch start precedes a group of elements The EXAMINE ON and GET elements in the memory access bran...

Page 63: ...he remote nodes which have access to write into specific blocks of data table as follows Node 020 can access Words 070 076 Node 017 can access Words 063 065 and Word 022 Node 010 can access Words 060...

Page 64: ...nd rung must be an EXAMINE ON instruction addressing a start bit Also you must end each command rung with an Energize Output 02707 element Figure 5 5 shows the format of a general command rung The sec...

Page 65: ...with this quality is received it is checked against the memory access rungs Unprotected means that a command with this quality overrides any memory access rungs put in to stop it As in Data Highway th...

Page 66: ...essage This is because two additional bytes are used per addresses over 177 for sending time critical messages However the size of a supervisory message is unlimited In the write block operation a blo...

Page 67: ...Write Bit with Reply Unprotected Write Bit with Reply Protected Write Bit Verified This format uses examine elements which address bits in the remote node These elements control remote node data tabl...

Page 68: ...In the preceding figures Figure 5 1 and Figure 5 3 through Figure 5 7 to specify the remote station we showed you EXAMINE ON elements where the word address designated the node However in some cases...

Page 69: ...en convert to octal and enter it When you are sending to the KFL User Designation 1 or 2 selects Channel 1 or 2 For example if you want to write to the second channel of a KFL you d put a 012 Very oft...

Page 70: ...nate user on time critical general command rungs However you cannot designate link on time critical command rungs because time critical commands can only be sent to nodes on the local link Commands to...

Page 71: ...iate access block must not exceed 21 words The word address in the EXAMINE OFF element must specify the local node which must match the link address thumbwheel setting The bit pointer in the EXAMINE O...

Page 72: ...ediate access blocks to be read from the remote node Use the addresses in the GET elements to define the start and end of a block of data table words to which the immediate access block is sent in the...

Page 73: ...rn on the start bit whenever and as often as your application requires Control the start bit through your ladder diagram program Turn it on when you want to send the command message to the remote node...

Page 74: ...ocal Station Data Table CAT NO 1779 KP2 PLC 2 DHII INTERFACE L1 L2 N GND NOTE Start Done and Remote Local Fault words must be adjacent Use one pair for each group of up to 8 commands Any accessible da...

Page 75: ...ways has a 1 in the next to last digit the done bit always has a 0 Figure 5 11 Adjacent Status Words 02707 03210 G G G A B Selection of Start Bit Word 033 Word 032 Automatically Desig Start Bits Done...

Page 76: ...11 shows that selection of the start bit in the program not only causes the PLC 2 DHII interface to control a corresponding done bit in that same word but also causes the PLC 2 DHII interface to cont...

Page 77: ...e Fault at Remote Node Processor Power Off at Remote Node Processor Error Detected in Communication Zone of Program at Remote Node Processor Local Fault Possible Sources Power Off at Remote Node Inter...

Page 78: ...When the PLC 2 DHII interface cannot carry out a command due to a programming error or a discrepancy in data it writes an error code into the error word you select in the header rung of the communicat...

Page 79: ...ves supplemental error or fault information depending on the type of error code displayed This value may have one of two meanings Reference Number Counter For Error Codes D2 through E7 the upper byte...

Page 80: ...at an operator s station can be a useful troubleshooting aid for quickly locating fault conditions Some hexadecimal codes will not display correctly on 7 segment BCD displays In this discussion you wi...

Page 81: ...ation When the local PLC 2 DHII interface receives the reply it turns on the done bit at the host processor The done bit in turn is examined in the ladder diagram program to turn off the start bit Aft...

Page 82: ...e interface has received the command message but is unable to execute the command at the host processor of the remote node For a summary of the distinction between these fault types refer to Figure 5...

Page 83: ...nterface Scan Command Response Time Remote ON OFF A B C D or Local Fault Bit Done Bit ON OFF Controlling the Start Bit Your program controls the start bit setting it on to initiate command execution t...

Page 84: ...in the event of a fault Only the done bit terminates attempts at command execution A local or remote fault bit response causes the program to re initiate command execution Do not confuse this type of...

Page 85: ...is arrangement the command message is sent only once Input 11111 must be turned off then on again to execute this command a second time In normal operation the start bit after successful command compl...

Page 86: ...Input 11111 is detected unlatched only when the done bit is set ON A compare bit 01111 in this example is used to manipulate the transition bit In Rung 2 the compare bit is controlled to match the ON...

Page 87: ...terval Figure 5 19 shows example rungs for this type of command initiation In this example Timed Bit 04615 is used to initiate the command at every preset interval 10 seconds This bit is examined to t...

Page 88: ...sfer attempts that result in local faults can take many times as much time as the normal message transfer time This could adversely affect the performance of other nodes You can reduce the impact of a...

Page 89: ...on 032 12 020 00 035 15 Timeout Transi tion Start Rung 3 PR 050 AC 000 032 02 Done Monitoring Remote Local Fault Bit When it cannot execute a command the PLC 2 DHII interface sets a remote or local fa...

Page 90: ...When used in this manner however a fault bit will be rapidly cycled ON and OFF if a fault is detected Because the fault bit can be constantly changing state at a rapid rate the program must use some...

Page 91: ...s to time when all the fault bits go OFF after one or more has been ON Bit 03015 the timed bit of the timer controls the output indicator As soon as a fault bit goes ON this bit goes ON thereby turnin...

Page 92: ...bit turns on Because of the asynchronous relationship you may not be able to do these types of functions accurately by examining fault bits directly Instead of examining the fault bits directly use a...

Page 93: ...he lower byte of the error word defined by the header rung Figure 5 23 Timeout Preset Significance Start Bit ON OFF Header Rung Representation Time Local Fault Bit Set if Timeout Occurs ON OFF Remote...

Page 94: ...lue For most applications a 5 second preset is acceptable The code for this timeout preset is 022 This code is used in all header rungs shown in this publication However there may be instances where a...

Page 95: ...ace is a backup function This automatic monitoring routine continuously checks PLC 2 DHII interface interaction with other nodes timing the execution of commands This automatic timeout does not check...

Page 96: ...rogram The preset value of this programmed TON instruction is not critical For this type of backup monitoring the programmed preset must exceed the timeout preset interval entered as a code in the hea...

Page 97: ...processor or the manual for its node interface Further general memory access limitations are discussed in the following sections Memory Access Rungs A remote node may have memory access rungs giving m...

Page 98: ...ning that storage bit in the program the desired effect is achieved Figure 5 25 Storage Bit Control Use Example 121 04 Storage Bit 010 01 111 13 Input Output 010 01 111 13 Input Output A Original Rung...

Page 99: ...set aside exclusively for control by these commands Note that this byte restriction for write bit commands does not apply to any but the PLC 2 family processors After you have generated a program at e...

Page 100: ...the source of the problem when a problem occurs within the local node Procedures for replacing a faulty board in the 1779 KP2 interface The 1779 KP2 interface has 21 LED indicators on its front panel...

Page 101: ...POWER ON AC POWER ON DATA HWY II PORT 2 ON AC POWER OFF FUSE SLOW BLOW 2A 250V DH II AUX ACCESS EXTENDED TAP CONFIG DATA HWY II PORT DATA HWY II PORT 2 PROGRAM INTERFACE PROCESSOR CAT NO 1779 KP2 DHI...

Page 102: ...tion or 3 a duplicate address exists MAC TEST On Yellow The MAC board is performing a self diagnostic test EXIT COMPLETE On Yellow This node has left the logical ring of the Data Highway II link IN RI...

Page 103: ...is reset the other nodes will not attempt to pass on the token to this node Press the EXIT REQUEST switch before turning off interface power or switching out of the RUN position If you don t press thi...

Page 104: ...the TEST position the interface will continuously execute the test cycle Leave the switch in the TEST position at least 15 seconds When you switch to the RUN position the interface will continue thro...

Page 105: ...ors or pins Avoid electrostatic damage by observing the following precautions 1 Press the EXIT REQUEST switch 2 When the EXIT COMPLETE indicator goes on turn off the AC POWER switch 3 Disconnect the A...

Page 106: ...ELECTABLE Green Grounding Conductor 6 Disconnect the cables from the front of the interface 7 Loosen the four thumbscrews on the front of interface 8 While holding the removable frame at the top and b...

Page 107: ...e 6 3 Rear View of the Removable Frame Assembly Shield Power Supply Board MAC Board Host Board 12617A Ribbon Cables 3M NO 3394 3M NO 3394 10 On the top two ribbon cable connectors locate the levers fo...

Page 108: ...e cable from the connector on the board 12 Remove all three ribbon cables CAUTION Electrostatic discharge can damage circuit board components To help prevent damage to circuit board components always...

Page 109: ...his caution could cause damage to the boards 20 Slide the removable frame back onto the stationary frame 21 Tighten the four thumbscrews on the front of the interface The thumbscrews must be tight to...

Page 110: ...steps Figure 6 6 1 Check the AC POWER ON indicator OFF If off check the AC POWER switch setting fuse AC source voltage and interlock switch If you still haven t found the source of the problem try re...

Page 111: ...Check the HOST FAULT indicator ON If on replace the host board OFF If off proceed to Step 4 4 Check the MAC FAULT indicator ON If on replace the MAC board OFF If off proceed to Step 5 5 Check the DUP...

Page 112: ...FF OFF OFF Green OFF ON ON ON Yellow Check AC POWER Switch Fuse Set the AC power switch to OFF wait 20 seconds then set the AC power switch to Replace host board Replace MAC board Press EXIT REQUEST S...

Page 113: ...des in Appendix B of this manual In this chapter we gave you information about individual indicators and switches as well as procedures for using them to operate the interface We also provided procedu...

Page 114: ...Cat No 1771 CR Communication Rate 1 megabit per second over Data Highway II Cabling RG 11 Type Coaxial Cable for Data Highway II See Publication 1779 6 3 1 Option for Data Highway II Cabling Redundanc...

Page 115: ...second token 1F Destination node specified is not on the link 22 Address for destination node is illegal 26 Data path between MAC and host boards temporarily blocked at local interface 2E Message buff...

Page 116: ...Local Errors Code Meaning 32 Cannot guarantee delivery of message Link layer time out or received 33 Duplicate token holder detected by link layer 34 Local port is disconnected 35 Attempt to send inva...

Page 117: ...le region DB Start bit not Bits 10 17 DC Unrecognized instruction after start bit DD GET for remote address expected DE GET for start address expected DF GET for end address expected E0 Start address...

Page 118: ...Croatia Cyprus Czech Republic Denmark Ecuador Egypt El Salvador Finland France Germany Greece Guatemala Honduras Hong Kong Hungary Iceland India Indonesia Ireland Israel Italy Jamaica Japan Jordan Ko...

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