Enhanced Programmable Logic Controller Gateway Implementation
Contents
1. 4 1 FACTORS LIMITING PERFORMANCE Although it is a very fast processor of data the EPLCG has finite computational capacity as its upper limit If the processing of input output data is restricted by the EPLCG s inability to perform required computations it is known as compute bound Limiting factors at the other extreme are baud rate and PLC I O delays If computations must wait for data to be received or transmitted the condition is called I O bound As baud rate is increased and or PLC I O delays are decreased performance improvement is linear and usually proportionate The performance improvement degrades however as compute limits are approached Statistics are maintained at various levels that can be used to monitor the performance of the EPLCG See EPLCG Planning Installation and Service manual subsection 4 3 2 for details and section 4 3 for how to display them 4 2 EFFECTS OF DATABASE COMPOSITION The performance of a database chiefly composed of analog inputs analog outputs and or counters numeric points is primarily limited by baud rate and PLC performance This is because numerics are easily processed in less than the 16 bit times reguired to transmit them to the EPLCG The performance of a database which is predominantly digital inputs and digital outputs Boolean points places a greater burden on computational power because only 1 bit time is available for processing 4 3 ADJUSTING AN EPLCG FOR PERFORMANCE2. D A EPLCG PERFORMANCE CONSIDERATIONS Factors Limiting Performance Effects of Database Composition Adjusting a EPLCG for Performance AAA wn INDEX EPLCG Implementation Guidelines i 9 97 EPLCG Implementation Guidelines i 9 97 INTRODUCTION Section 1 This section summarizes the Enhanced Programmable Logic Controller Gateway implementation tasks lists publications that you will refer to in order to implement EPLCGs and describes implementation dependencies 1 1 SUMMARY OF EPLCG IMPLEMENTATION TASKS While most of the the information in this publication relates to Enhanced Programmable Logic Controller Gateway EPLCG functions EPLCG data points and EPLCG operating considerations other implementation activities must also be completed to make the EPLCG functional The Engineering Personality activities listed below may be affected by the implementation of a EPLCG or must be used to implement a EPLCG See subsection 1 2 for references to instructions for each of the activities listed below Activities named in THIS TYPEFACE are activated by targets on the Engineering Personality Main Menu UNIT NAMES The process units defined for each EPLCG data point are established in this activity AREA NAMES The area name and descriptor for any units with EPLCG points that are assigned to an area are established in this activity LCN NODES Identifies and defines the nodes on the Local Control Network In the case
3. Of the factors affecting EPLCG performance the most significant is baud rate As a rule of thumb doubling the baud rate will double performance If you are already running at the maximum baud rate consider dividing the database between the EPLCG s two ports if possible When pinned for redundant communications the EPLCG will automatically divide data requests between the two ports This has the same effect as doubling the baud rate Pinning the EPLCI board to double buffer Data Requests pipelined operation will also improve performance See EPLCG Planning Installation and Service manual subsection 3 2 3 4 for pinning information At the PLC end a dedicated communications module should be used if supported by the PLC These modules usually contain a dedicated processor that utilizes a high speed access mechanism such as DMA to access the PLC data The EPLCG requests data in blocks of up to 64 words Unused data elements in the block will be read and discarded For example two 30 word blocks separated by 4 unused words will be collected as a single 64 word block This is faster than two 30 word requests If a 60 word block is preceded or followed by unused words only the 60 word block will be requested By using consecutive storage elements within the PLC the amount of excess data requested by the EPLCG can be reduced Contiguous addressing of the PLC data elements provides optimum performance because Modbus and Allen Bradley protocol speci
4. and the point will continue to be read from the PLC as long as the PCADDRxy and SPECIFxy or PCBITxy parameters are non zero This is commonly referred to as a ghost point Startup publications references EPLCG Implementation Guidelines 3 6 9 97 3 2 3 PUBLICATION TITLE BINDER TITLE A EPLCG Planning Installation and Service Implementation EPLC Gateway B EPLCG Specification and Technical Data Implementation EPLC Gateway C LCN Site Planning System Site Planning D LCN System Installation LCN Installation E LCN System Checkout LCN Installation PUBLICATION TITLE BINDER TITLE F System Startup Guide Cartridge Drives Implementation Startup and Reconfiguration 1 G System Startup Guide CD ROM Implementation Startup and Reconfiguration 1 H System Startup Guide Zip Disk Implementation Startup and Reconfiguration 1 J EPLC Gateway Implementation Guidelines Implementation EPLC Gateway J Data Entity Builder Manual Implementation Engineering Operations 1 K Engineer s Reference Manual Implementation Startup and Reconfiguration 2 L EPLC Gateway Forms Implementation EPLC Gateway M EPLC Gateway Control Functions Implementation EPLC Gateway N EPLCG Parameter Reference Dictionary Implementation EPLC Gateway NOTE Release 530 and later software updates are distributed only on Zip Disks and CD ROM 3 2 3 Saving of EPLCG and DHP Data After its initial startup you can begin to build the database for your EP
5. EPLCG Implementation Guidelines 3 1 9 97 3 1 1 3 1 1 DHP Point Planning Guidelines Below is a list of items to consider when implementing DHP points in the EPLCG 1 To avoid potential confusion by operators do not configure more PC devices in the DHP box slot entity HYnnBxx than necessary Additional devices can be added later if needed Plan or map the PLC addresses carefully and use contiguous PLC addresses as much as possible for the most efficient data transfers To avoid interaction between DHP points Do not configure more than one DHP point to access the same PLC memory location e Do not use the same slot subslot for more than one DHP point tag Remember that dual input and dual output points require configuration of the first subslot only with the next higher subslot in the same slot automatically assigned to the second input or output All points in a DHP slot should have the same PC device index This will avoid a loss of view to some points accessing data in a good PLC because of a failure in another PLC device A PC device failure will FAIL all points in any DHP slot for which at least one subslot is configured to access the failed PC device Note that the DHP box will enter a temporary RESET condition whenever the DHP box slot entity HYnnBxx is loaded e a DHP point is loaded to that box except for load from checkpoint certain DHP parameters are changed from the point detail display These
6. EPLCG Implementation Guidelines 9 97 Table of Contents 1 INTRODUCTION 1 1 Summary of EPLCG Implementation Tasks 1 2 References 1 2 1 References for Engineering Activities 1 2 2 References for Hardware Implementation 1 3 EPLCG Implementation Dependencies 2 HIWAY AND BOX SLOT CONFIGURATION Purpose of the Hiway and Box Slot Entities Hiway and Box Slot Entities to be Built Hiway Entities Box Slot Entities Order for Hiway and Box Slot Entity Building Hiway Configuration Hiway Number Hiway Traffic Director Functions Sequence of Events Synchronization Box Slot Configuration EPLCG Data Hiway Addresses Emulated DHP Hiway Address Assignments EPLCG and DHP Box Assignment Event Processing Change Detection Ro NO RO D RO D D D D D D I D NO NO anann ER RG NA O1 BB D OO D D o EPLCG OPERATIONAL CONSIDERATIONS The EPLCG Subsystem DHP Point Planning Guidelines Loading Saving and Restoring of EPLCG Data EPLCG Initial Startup or Restart Initial Startup of a EPLCG Saving of EPLCG and DHP Data Restoring EPLCG and DHP Data Recovering from Checkpointing and Loading Errors Recovery from DHP Point Configuration Errors EPLCG Functions Redundant Gateways Redundant Communication Allen Bradley Communication Redundancy Additional Features Nonredundant Communication to Allen Bradley PLC 5 MODBUS Digital Outrput Scan Suppression G9 G9 G9 CD o B B W WW W W V V W w Go Go Go Go w I VV D D D D gt O1 B D O O1 R
7. EPLCG pair as a node or node pair on the LCN 3 Perform a volume configuration to provide checkpoint space on a History Module within your system 4 Complete the EPLCI board pinning in the EPLCG s and the EPLCG relay panel pinning on the back of the EPLCG s EPLCG Implementation Guidelines The connection between the EPLCG s and the PLC s will be discussed in a later step The EPLCG configures as a Hiway Gateway HG and looks exactly like an HG to the operator If the EPLCG is redundant you will need to enter the Redundant Node Number ID the two digit LCN node number You will be asked to enter a two digit Hiway number 01 20 Although having a checkpoint on your LCN network is not absolutely mandatory you could store it on removable media it is highly recommended Do not simply add a directory to an existing volume on an HM EPLCG parity can be either odd or even no parity is not an option If you chose Redundant Allen Bradley for the relay panel pinning the port 1 and port 2 pinning of TS2 on the EPLCI board must be for identical baud rate and parity TS3 jumper settings must match the installed configuration and be the same in both nodes of a redundant pair 3 4 Refer to the publications listed by these letters below for useful information you may need to accomplish each task A B C D E 9 97 3 2 2 STEPS NOTES REFERENCE 5 THROUGH 8 PUBLICATIONS 5 Complete t
8. for data points including EPLCG data points are used and displayed in a given process area The area database is the database loaded into a Universal Station so that the database defines the process area monitored and controlled through the US Control Language CL The EPLCG does not have a CL program feature but CL AM programs can read from and write to EPLCG data points Ladder Logic Programming The make and model of the PLC s connected to the EPLCG can widely differ so the Honeywell IAC publications do not provide information for ladder logic programming Consult the manuals provided by the PLC vendor s 1 2 REFERENCES 1 2 1 References for Engineering Activities UNIT NAMES and AREA NAMES Network Form Instructions in the Implementation Startup and Reconfiguration 1 binder Network Data Entry in the Implementation Startup and Reconfiguration 1 binder VOLUME CONF IGURATION Section 7 of the Engineer s Reference Manual in the Implementation Startup and Reconfiguration 2 binder For the EPLCG checkpoint volume s follow the instructions for HG checkpoint volumes APPLICATION MODULE Application Module Control Functions in the Implementation AM 1 binder Application Module Algorithm Engineering Data in the Implementation AM 1 binder Application Module Parameter Reference Dictionary in the Implementation AM 1 binder Data Entity Builder Manual in the Implementatio
9. functionally unnecessary Therefore always select ThisHG as the value for parameter HWYHTD in the hiway entity 2 4 3 Sequence of Events Synchronization The EPLCG does not support sequence of events synchronization therefore always select Disable as the value for parameter SOES YNCH in the hiway entity 2 5 BOX SLOT CONFIGURATION The type of box on the Data Hiway HG for the EPLCG and DHP for the emulated boxes is defined in this task as is each device s address on the hiway You must configure a box slot entity for each EPLCG in an EPLCG pair and you must configure a box slot entity for each DHP for which you intend to build data points After selecting BOX SLOT CONFIG for the BOXTYPE parameter select HG to configure an EPLCG box slot entity and select DHP to configure a DHP box slot entity 2 5 1 EPLCG Data Hiway Addresses Assign the first EPLCG to hiway address 02 and assign its partner if present to hiway address 03 Confirm that the EPLCI jumper is in the correct position for redundant or nonredundant EPLCG Refer to the EPLCG Planning Installation and Service manual for details of EPLCI jumper options 2 5 2 Emulated DHP Hiway Address Assignments Assign the emulated DHPs to hiway addresses 08 through 15 2 5 3 EPLCG and DHP Box Assignment The EPLCG does not support remote or added gateways as does the HG so always configure ThisHG as the value for the BOXASSN parameter in both the EPLCG box slot entities and the D
10. of EPLCGs this activity defines the node numbers for the EPLCGs and the process network number for the EPLCGs emulated Data Hiways Note that because the EPLCG is supported by the Hiway Gateway software you configure EPLCGs as if they were HGs VOLUME CONFIGURATION The EPLCG HG checkpoint volume s amp 7np is established in this activity Volume amp 7np must have adequate storage space to accommodate the EPLCG checkpoint data including the data for its emulated DHPs boxes APPLICATION MODULE Any AM points that are members of a control strategy that includes EPLCG points are built in this activity Connections to the EPLCG points are defined in tagname parameter form HIWAY GATEWAY The Hiway point which defines the EPLCG s emulated Data Hiway and the Box Slot points that define the functions and content of the emulated DHPs are built in this activity Also the EPLCG data points are built in this activity PICTURE EDITOR FREE FORMAT LOGS BUTTON CONFIGURATION Any of pictures logs and buttons built by these activities can access EPLCG points once the points are built and loaded EPLCG Implementation Guidelines 1 1 9 97 1 2 HM HISTORY GROUPS EPLCG data point values for which continuous history is to be collected are defined in this activity by assigning them to specific HM history groups AREA DATA BASE This activity defines how and where data
11. s LCN NODE HM HISTORY GROU Figure 1 1 EPLC Gateway Implementation Dependencies EPLCG Implementation Guidelines 1 4 9 97 HIWAY AND BOX SLOT CONFIGURATION Section 2 This section provides guidelines for building hiway and box slot configuration entities for each EPLC Gateway 2 1 PURPOSE OF THE HIWAY AND BOX SLOT ENTITIES Each hiway entity point defines for the LCN system the emulated Data Hiway Each box slot entity defines for the LCN system the HG EPLCG box es or one of the emulated Data Hiway Ports DHPs in the EPLCG and each slot in each DHP 2 2 HIWAY AND BOX SLOT ENTITIES TO BE BUILT The EPLCGs in an EPLCG pair always use hiway addresses 02 and 03 on the emulated Data Hiway The emulated DHPs in each EPLCG or EPLCG pair always use hiway addresses 08 through 15 For more information about this addressing scheme refer to subsection 2 5 in EPLC Gateway Control Functions in the LCN Implementation EPLC Gateway binder 2 2 1 Hiway Entities You must build a hiway entity for each EPLC Gateway Each LCN can have up to 20 process networks Each Data Hiway or Universal Control Network is one process network so the sum of EPLCG Hiway Entities Hiway entities for Data Hiways connected to HGs and UCNS cannot exceed 20 Please note the emulated hiway counts as a process network even though is not a physical hiway Hiway entities are reserved entities that is they are e
12. slot subslot and making a new checkpoint file SYMPTOM DHP slot card failures or PC device errors occur after changing DHP slot type or making a slot NotConfigured CAUSE To properly change DHP slot type all the points in the slot must be deleted Be sure to delete the points properly by first setting PCADDRxy SPECIFxy or PCBITxy parameters to zero 0 If the slot appears empty of points but the slot type change is still unsuccessful or causes errors there are probably ghost points in the unused subslots Be sure the subslots are clear by loading a dummy point to every subslot and setting the PCADDRxy SPECIFxy or PCBITxy parameters to zero 0 then deleting the dummy point s EPLCG Implementation Guidelines 3 10 9 97 3 2 6 Worst Case Scenarios When slot or PC device failures elude your best efforts to clean up configuration errors more drastic measures may be required to load a clean database This involves clearing the database in the DHP box or entire EPLCG then restoring from Exception Build EB files or Intermediate Data Files IDF Follow these steps 10 11 12 13 Save the existing database by executing SAVE ALL BOXES to NET and to removable media Do not use these files except in an emergency since the checkpoint is suspected of containing ghost points Also note that failed DHP boxes will not be saved so you may need to retain older checkpoint files made prior to the DHP failure B
13. the A B device physically linked to the PLCG see the box slot configuration example below All stations on the communications link are numbered in octal Each station should have a unique station address Use EPLCG parameter PCn TYPE model type APLC for correct binary value format when interfacing PLC 5 in PLC 2 emulation mode Selection of other model types results in communications of values in BCD format The PCnPORTA parameter value must be the same as the DH address of the target PLC 5 processor see the box slot configuration example below EPLCG Implementation Guidelines 3 17 9 97 3 3 4 3 3 4 2 Box Slot Configuration Example In the figure below we will use an example of an EPLCG interfacing through an Allen Bradley KE or KF module by way of the Allen Bradley Highway Plus DH to a single Allen Bradley PLC 5 Allen Bradley KE or KF Module KE KF station address must equal PLC 5 file number f Refer to Note 2 PCnPORTA must equal PLC 5 station address Refer to Note 1 Allen Bradley PLC 5 Note 1 First the following two items have to match The PCnPORTA in the DHP box point database octal e The station address of the PLC 5 octal Example The PLC s station is 10 octal This is made as an entry of 10 octal as the PC1PORTA entry for DHP device one Note 2 In addition the following two items have to match The station address of the KE or KF module octal e The integer file number
14. BUS Digital Output Scan Suppression Because the jumper TS3 Pin 2 used to select nonscanning Modbus Digital Outputs has been reassigned an alternate method of configuring these points has been provided Scan suppression of Modbus Digital Outputs is now a software configuration option The selection of nonscanned Modbus outputs is made in a manner similar to the selection of Allen Bradley report by exception To create a nonscanning Modbus output analog or digital the programmer must first create a logical Modbus PLC configured on the actual port 2 port 3 or 4 Then configure any nonscanned output points against this logical PLC Any attempt to configure an input point analog digital or counter against a nonscanning logical PLC will result in a configuration error being returned 3 3 5 1 Use of Holding Registers in Modicon PLCs The holding registers in Modicon and Modicon compatible PLCs can be used as sources of EPLCG digital input data thereby increasing throughput by transferring blocks of digital data rather than single bits To do so a Digital Input or Digital Composite point s subslot address in parameter INPTSSLT specifies the bit to input from the holding register as follows Subslot number in INPTSSLT 16 15 14 02 01 Holding register bit number 16 15 14 02 01 EPLCG Implementation Guidelines 3 19 9 97 EPLCG Implementation Guidelines 3 20 9 97 EPLCG PERFORMANCE CONSIDERATIONS Section 4
15. C database is generally divided into blocks and when a change is detected in a block the entire block is sent to the EPLCG The PLC tries to send the RBE message through either route CIM 21A or 21B If the message fails the PLC should retransmit the data on the other route If the message transfer is successful no further effort is required until the next data change is detected Retry handling is determined by the PLC programmer The system becomes more complex for a redundant EPLCG as shown in Figure 3 3 The roles of primary and backup EPLCG are arbitrary Again the addresses of the Allen Bradley CIMs and PLC are for illustration only Primary EPLCG EPLCI EPLCI I O Card I O Card KE Network B EPLCGs access PLC file 25 decimal matches PLC octal address 31 16695 Figure 3 3 Redundant EPLCG with Redundant Allen Bradley Communications When a database change is detected by the PLC the ladder logic must report the change to both EPLCGs primary and backup When the redundant communications option of a redundant gateway EPLCG is enabled Allen Bradley PLC 5 series controllers should be configured using the APLC215 target The use of APLC215 with redundant communications causes the EPLCG firmware to use the Logical ASCII addressing mode to bypass the PLC 5 s default
16. HP box slot entities 2 5 4 Event Processing The emulated DHPs support the generation and reporting of events Process Alarms Process Changes etc The parameter EVENT PRC should be set to ENABLE to allow routing of these events through the EPLCG to the LCN EPLCG Implementation Guidelines 2 3 9 97 2 5 5 2 5 5 Change Detection Because there are no other Masters on the Emulated Hiway in the EPLCG there is no need to signal or detect changes made by other Masters The CHNG FLAG parameter should be set to NOT CONFG EPLCG Implementation Guidelines 2 4 9 97 EPLCG OPERATIONAL CONSIDERATIONS Section 3 This section describes operational characteristics of PLC Gateways EPLCGs that you should consider during EPLCG implementation 3 1 THE EPLCG SUBSYSTEM The EPLCG appears to the remainder of the LCN based system to be a Hiway Gateway HG with a Data Hiway and up to eight Data Hiway Ports It is supported by the HG software with no modifications Therefore all standard displays including status displays Group displays Detail displays and Engineering Personality displays are the same as if the EPLCG was an HG including all HG Data Hiway and DHP terminology DATA HIWAY PORTS 182 Short Haul Modems or Communication Interfaces Q W E lt LL LL oc lt gt lt Z lt a Q Z lt o LL X O m Figure 3 1 Emulated Data Hiway and DHPs in the EPLCG Subsystem
17. Honeywell Enhanced Programmable Logic Controller Gateway Implementation Guidelines EP12 400 Tetal Plant Honeywell Implementation EPLC Gateway Enhanced Programmable Logic Controller Gateway Implementation Guidelines EP12 400 Release 430 9 97 Tetal Plant Copyright Trademarks and Notices Copyright 1992 1997 by Honeywell Inc Revision 02 September 20 1997 While this information is presented in good faith and believed to be accurate Honeywell disclaims the implied warranties of merchantability and fitness for a particular purpose and makes no express warranties except as may be stated in its written agreement with and for its customer In no event is Honeywell liable to anyone for any indirect special or consequential damages The information and specifications in this document are subject to change without notice Honeywell TotalPlant and TDC 3000 are U S registered trademarks of Honeywell Inc Other brand or product names are trademarks of their respective owners About This Publication This publication summarizes the Enhanced Programmable Logic Controller Gateway EPLCG implementation process guides you to procedures and references you need to implement EPLCGs defines the hiway and box slot entities you must build for each EPLCG and describes EPLCG operation considerations in implementing and using EPLCGs This publication supports Release 430 EPLCG Implementation Guidelines 9 97
18. LCG s including the data points and hiway and box slot entities described in Section 2 These entities points are built with the Data Entity Builder which you activate by selecting HIWAY GATEWAY on the Engineering Main Menu As you load points into the EPLCG and during operation you should periodically checkpoint save your EPLCG and DHP data on an HM or removable media cartridges or floppies Use the SAVE DATA target on the Hiway Status display to request a demand checkpoint You can enable automatic periodic checkpointing to an HM through the AUTO SAVE target on the Gateways and Interfaces display you should disable periodic checkpointing while you are building data points For more information on checkpointing refer to Section 21 of the Engineer s Reference Manual in the Implementation Startup and Reconfiguration 1 binder EPLCG Implementation Guidelines 3 7 9 97 3 2 4 During initial configuration we recommend that in addition to checkpoints being saved automatically on an HM you periodically reguest demand checkpoints through the SAVE DATA target on the Hiway Status display to be stored on removable media This will serve as backup data if the HM should become unavailable We do not recommend copying checkpoint files from an HM to removable media because if more than one cartridge or floppy is needed the data for one unit may be split between cartridges or floppies and such data cannot be reloaded After install
19. PLC 2 emulation file processing The PCxPORTA parameter for the DHP box must be set to the station address of the PLC and a file of the same number after conversion to decimal must be used in that PLC for EPLCG access EPLCG Implementation Guidelines 3 15 9 97 3 3 3 Numeric data is still transferred in binary format Keying the use of the APLC215 target with the redundant communications option was done to remain backwards compatible with existing PLCG installations Selecting APLC215 without redundant communications will condition the EPLCG to expect a member of the PLC 2 series and numeric data to be transferred in BCD format 3 3 3 4 Reconnect Lockout After the EPLCG determines that an Allen Bradley PLC is not visible on either port reconnect attempts are locked out for a 1 second period At the end of the 1 second lock out a reconnect will be attempted On one port if it is unsuccessful the 1 second lock out will be triggered again and the next attempt will be made using the other port This sequence will repeat as long as necessary The 1 second lock out prevents the EPLCG from overloading this A B network during reconnect attempts 3 3 3 5 Best View Failover The Allen Bradley Data Hiway protocol allows multiple masters and with redundant communications selected each redundant EPLCG maintains an indicator of the number of visible PLCs These indicators are compared and if the back up EPLCG has a better view for a
20. YnnB02 3 on the hiway then DHP boxes SH YnnB08 15 on the hiway then DHP points Use Exception Build in the DEB to load the box slot and DHP point entities from the EB files created earlier DO NOT reload the point data from checkpoint files since these are suspected of containing the ghost points which caused the original problems Compare the new EPLCG database to the old one to check for errors Use the prebuilt DocTools Query saved earlier to document the EPLCG database and save results to a file then compare the old and new DocTool query results Save the new EPLCG database by doing SAVE ALL BOXES to NET Do it twice to update both file sets This completes the process and the ghost points have been eliminated EPLCG Implementation Guidelines 3 11 9 97 3 3 3 3 EPLCG FUNCTIONS 3 3 1 Redundant Gateways EPLCGs can be configured stand alone or in redundant pairs When configured as a redundant pair the primary EPLCG uploads initial database information to and synchronizes with the secondary EPLCG through the interboard link The backup EPLCG will monitor the communication between the primary EPLCG and the PLC s thereby maintaining an up to date copy of the current database 3 3 1 1 Interboard Link The interboard link connection between the EPLCI I O cards or through the Relay Panel with PLCI I O cards allows firmware revision compatibility checks between the primary and secondary EPLCGs to be performed immediately af
21. ackbuild the EPLCG database to create EB files for desired points Use the DEB Data Entity Builder or DocTools to create selection lists EL files for all DHP points Put the Hiway SHIWAY and box slot SHYnnBxx entities in a separate list from the DHP points From the DEB Print System Entities to create the EB files using the EL files just created Document the existing database using Doc Tools Build a DocTools guery with the following parameters BOXNUM SLOTNUM INPTSSLT OUTSSLT PNTBOXIN PCADDRII SPECIFI1 PCBITI1 PCADDRI2 SPECIFI2 PCBITI2 PNTBOXOT PCADDRO1 SPECIFO 1 PCBITO1 PCADDRO2 SPECIFO2 PCBITO2 These are the parameters that provide the unique correlation between DHP box slot subslot location and PLC memory Save this query for later use Run the query then sort the results using BOXNUM SLOTNUM and INPTSSLT in the Field Name List Output the results to a file and save for later use Prepare for Loss of View and Loss of Control then clear the existing database Depending on the severity of the problem it may suffice to clear only the DHP database with the CONFIG CLEAR command for the affected DHP Worst case shutdown both EPLCG nodes if redundant and cycle power on the nodes Reload the EPLCG by following subsection 3 2 2 Initial Startup of an EPLCG in this Implementation Guidelines manual Be sure to load in the order shown EPLCG node on LCN then HIWAY entity then EPLCG entities SH
22. ation is complete we recommend disabling automatic checkpointing on an EPLCG DHP and doing manual checkpoint save after configuration changes Because automatic checkpoint does not save data for a DHP in any state other than OK it is possible to have incomplete checkpoint files due to communication link errors between EPLCG and a PLC or due to accidental errors during configuration changes NOTE It is possible to save data for individual DHPs boxes but before you can do so you must have saved a complete checkpoint for the EPLCG and all its emulated DHPs Because the DHPs are not really individual physical boxes but are integral parts of the EPLCG it is probably best to select ALL BOXES rather than individual boxes This ensures that all data changes in the EPLCG and all DHPs are saved 3 2 4 Restoring EPLCG and DHP Data EPLCG and DHP data can be restored from checkpoint files through the LOAD DATA target on the Hiway Status display A successful load replaces any data in the EPLCG and DHP s with data from the checkpoint files These loads can be directed to any box DHP or you can select ALL BOXES to direct the load to all DHPs NOTE After reloading the EPLCG personality all configured DHPs will have A80 Address Errors These errors must be cleared using the INIT ADDR command in the Hiway Command Menu from the Hiway Status Display The configured DHPs will now be in Reset The DHP data can now be re
23. ception building or the use of the load Data Point s multiple command with IDFs HYnnB08 MAD After the initial load of a sa 15 DHP there will be an associated A80 addressing error seen from the Hiway Status Display To clear the error perform an INIT ADDR command from the HIWAY COMMANDS function Then reload each and every DHP Box Slot Data Point again DO NOT PROCEED WITHOUT COMPLETING THIS PROPERLY Each emulated DHP should come up in the RESET mode Performance of an ENABLE PROCESSING command should make each DHP go to an OK state 10 Build and load The DHP box must be in BASIC control H I J K L M data Point s state to load points Points will not load if DHP is in FULL control state One point is enough to cause communications to start between the EPLCG s and a PLC Thus it is recommended that only one point be built and loaded before going further Perform a demand checkpoint now This way you will have something to go back to in case of a power failure or equipment malfunction It is best to do a save using the ALL BOXES target to insure saving both the HG and DHP box portions of the database NOTE When deleting a DHP point with the DELETE ENTITY function of the Data Entity Builder DEB be sure to first set to zero 0 the PCADDRxy and SPECIFxy Modbus or PCBITxy Allen Bradley digital parameters for the DHP point The DELETE ENTITY function does NOT delete point data from the emulated DHP box memory
24. created in the PLC 5 decimal Example The KE or KF module s station address is 20 octal This octal number converts to 16 decimal as the file number created in the PLC 5 16782 Figure 3 4 EPLCG Interfacing through an Allen Bradley KE or KF Module EPLCG Implementation Guidelines 3 18 9 97 3 3 4 3 3 4 3 Process Point Example When building any point in the EPLCG use PCADDRIn or PCADDROn equal to the address element of the data in the PLC 5 integer file that was created for EPLCG access For example 1f the data for an EPLCG analog input is in PLC 5 location N16 22 use PCADDRII 26 octal for the EPLCG analog input point Note that for PCADDRIn and PCADDROn a value of 0 zero is illegal for the PLC and will cause the point to not be scanned by the EPLCG Values on the EPLCG point are in octal while those in the PLC are in decimal In addition when building a digital point in the EPLCG the EPLCG parameter PCBITIn or PCBITOn specifies which bit position an EPLCG digital point occupies within the PLC 5 integer file register Once again values on the EPLCG point are in octal while those in the PLC are in decimal For more details on EPLCG parameters refer to the EPLCG Parameter Reference Dictionary PLO9 540 or equivalent For pinning options on the PLCI board refer to the EPLCG Planning Installation and Service manual PLO2 500 or equivalent as well as recommendations on Allen Bradley interface module settings 3 3 5 MOD
25. e error select Init Addr from the Hiway Command menu under the Hiway Status Display Load the DHP Box Slot Configuration a second time This time there should be no errors The reserved entities that are defined by these tasks must be loaded in the order listed above This means you must use individual Load commands to load the entities separately in this order or you must use a Load Multiple command that loads them together in the proper order For a Load Multiple command the order in which the entities are loaded is specified by the order that the entity names appear in the selection list file You could also load these entities from an exception build source file EB file In the EB file entities must be listed in the proper order 2 4 HIWAY CONFIGURATION The emulated Data Hiway in an EPLCG is not a physical process network so the EPLCG does not have remote or added gateways as does the Hiway Gateway 2 4 1 Hiway Number Each pair of EPLCGs a primary and secondary on an LCN is assigned a unique process network number 01 through 20 The process network number identifies the hiway database to be used by the EPLCG pair EPLCG Implementation Guidelines 2 2 9 97 2 4 2 2 4 2 Hiway Traffic Director Functions Because there is no physical Data Hiway associated with an EPLCG or EPLCG pair the EPLCG has complete control over all transactions on the emulated Data Hiway so a Hiway Traffic Director HTD is physically impossible and
26. fy start address and number of elements to include in any transfer EPLCG Implementation Guidelines 4 1 9 97 4 3 After point load or reconfiguration of some parameters the EPLCG will sort all PLC database addresses before starting to request data so the order of the points in the emulated DHP is not critical As long as the PLC data elements are contiguous the desired result will be achieved The EPLCG automatically makes adjustments to optimize write performance to the PLCs Single point outputs are interleaved with scan reguests in the next available port buffer The EPLCG reduces its read request block size from 64 words to 8 words only while an output is pending improving output rate by as much as three times Output requests from other LCN nodes are stacked in a request buffer and are output in the order they are received Excessive writes to PLCs can significantly reduce overall EPLCG performance EPLCG Implementation Guidelines 4 2 9 97 Index Topic Section Heading Actions for Error Recovery Activating Reporting by Exception Addresses Assignments for Emulated DHP EPLCG Adjusting a EPLCG for Performance Allen Bradley PLCs Reporting by Exception Assignment Box EPLCG and DHP Box Assignment EPLCG and DHP Box Slot and Hiway Entities To be Built Purpose Building Order Configuration Box Slot Configuration and Hiway Configuration Building Order for Hiway and Box Slot Entity Change Detection and Event Processing Checkpoi
27. he This is a good time to complete any dip cabling between switch settings and or configuration in the the EPLCG relay PLC s you are interfacing to panel or I O card and the PLC s Power on the The null checkpoint files are on floppy EPLCG s and volume amp HGC cartridges amp CR6 or load it them with amp C6 the HG null The directory names are amp I01 through checkpoint 120 corresponding to the appropriate hiway number chosen The file name that will be loaded is HGOxxMAS CP where xx corresponds to the appropriate hiway number chosen e At the Gateway Status display the EPLCG s should show as OK for the primary HG and Backup for the redundant HG if present 7 Build and load the The EPLCG configures as a Hiway EPLCG Hiway Gateway HG and looks exactly like an Data Point HG to the operator SHIWAYnn 8 Build and load the IMPORTANT Do not build and load any EPLCG Box Data of the DHP Box Slot Data Points until this Point s step is complete HYnnBO2 and The EPLCG configures as a Hiway HYmnBO3 if Gateway HG and looks exactly like an redundant HG to the operator For the primary EPLCG the box number has only one valid choice and it is 02 e For the backup EPLCG the box number has only one valid choice and it is 03 EPLCG Implementation Guidelines 3 5 9 97 3 2 2 STEPS NOTES REFERENCE 9 AND 10 PUBLICATIONS 9 Build and load the IMPORTANT Do not do this by DHP Box Slot ex
28. he data image consists of previously checkpointed data or null checkpoint a set of Honeywell provided checkpoint files with no point data The data that is loaded from the Gateway and Interfaces display does not include data for the emulated DHPs which is loaded or restored through the Hiway Status display for more information see subsection 3 2 2 Do nat try to load both EPLCGs in an EPLCG pair concurrently one of the EPLCGs will fail Complete loading one of the EPLCGs as the primary then the other EPLCG can be loaded as the secondary For more information about starting or restarting EPLCGs refer to the information about loading of gateways and HG modules in Section 15 of the Process Operations Manual in the Process Operations binder For instructions for using null checkpoints in the initial startup of an EPLCG refer to Task 18 in the System Startup Guide in the Implementation Startup and Reconfiguration 1 binder EPLCG Implementation Guidelines 3 3 9 97 3 2 2 Initial Startup of an EPLCG 3 2 2 A summarized example of 10 steps required to start up an EPLCG are presented in this table Publication references given in this section are here for convenience to the startup effort and some are duplicates of those in the list in subsection 1 2 STEPS NOTES REFERENCE 1 THROUGH 4 PUBLICATIONS 1 Physically install the EPLCG or redundant EPLCG pair including power grounding and LCN cabling 2 Configure the EPLCG or
29. ice in the Implementation EPLC Gateway binder 1 2 2 3 Service Five Ten Slot Module Service in the LCN Service 1 binder Enhanced Programmable Logic Controller Gateway Enhanced Programmable Logic Controller Gateway Planning Installation and Service in the Implementation EPLC Gateway binder EPLCG Implementation Guidelines 1 3 9 97 1 3 1 3 EPLCG IMPLEMENTATION DEPENDENCIES Figure 1 1 shows which EPLCG implementation tasks depend on information entered in other tasks This figure does not necessarily dictate the order in which the tasks must be completed but it does show all dependencies that must be satisfied before the EPLCG can be fully operational CONSOLE NAMES AREA DATA BASE AREA NAMES N PLC Address Assignments and Ladder Logic Programming Process Operations Standard Operational VOLUME CONFIGURATION Displays and Reports PICTURE HG EPLCG Checkpoint EE FORMA Volume s User Built Schematics Free Format Logs EB Files or IDFs Cont Hist Volumes User Volumes for Storage of CONF IGURA Buttons Nx History Collection and Retrieval OA HIWAY GATEWAY a HIWAY CONFIG a BOX SLOT CONFIG gt Control Language HG PROCESS POINT BUILD TYPE
30. n Engineering Operations 1 binder HIWAY GATEWAY EPLCG System Control Functions in the Implementation Startup Reconfiguration 2 binder EPLCG Implementation Guidelines 1 2 9 97 1 2 2 Enhanced Programmable Logic Controller Gateway Control Functions in the Implementation EPLC Gateway binder Enhanced Programmable Logic Controller Gateway Parameter Reference Dictionary in the Implementation EPLC Gateway binder Data Entity Builder Manual in the Implementation Engineering Operations 1 binder PICTURE EDITOR FREE FORMAT LOGS BUTTON CONFIGURATION Instructions for these activities are in the Implementation Engineering Operations 2 binder HMHISTORY GROUPS HM History Group Form Instructions in the Implementation Engineering Operations 1 binder Data Entity Builder Manual in the Implementation Engineering Operations 1 binder AREA DATA BASE Area Form Instructions in the Implementation Engineering Operations 1 binder Data Entity Builder Manual in the Implementation Engineering Operations 1 binder 1 2 2 References for Hardware Implementation 1 2 2 1 Site Planning LCN Site Planning manual in the System Site Planning binder Enhanced Programmable Logic Controller Gateway Planning Installation and Service in the Implementation EPLC Gateway binder 1 2 2 2 Installation and Checkout Enhanced Programmable Logic Controller Gateway Planning Installation and Serv
31. nitial Startup of a EPLCG Installation and Checkout Interboard Link Introduction Loading and Checkpointing Errors Loading Saving and Restoring of EPLCG Data Logical ASCII Addressing with Redundant Communications Modicon PLCs Holding Registers Number Hiway Nonredundant Communication to Allen Bradley PLC 5 Operational Considerations Order for Hiway and Box Slot Entity Building EPLCG Box Assignment Data Hiway Addresses Functions Initial Startup of a EPLCG Initial Startup or Restart Operational Considerations Performance Considerations Subsystem Publication References Purpose of the Hiway and Box Slot Entities Recommended Actions for Error Recovery Recovery Checkpointing and Loading Errors DHP Point Configuration Errors Errors FILE ERROR Redundant Communication Redundant Gateways References Engineering Activities Hardware Implementation Registers Holding in Modicon PLCs Reporting by Exception in Allen Bradley PLCs Activation of Restart or Startup Restoring EPLCG and DHP Data Saving of EPLCG and DHP Data Checkpointing ADR D D D D D NS ae NIUE N w wHBRwHONH ND 00 Bow OF IO 00 0 ND 0 GO CO GO GO GO GO N D O1 01 NS 40W D D gi Zi OW CD CD CD CD IAN CD ND D UD CO CO CO NN NN DE amp amp D D D G D D D D a ND DN Ow EPLCG Implementation Guidelines Index 2 9 97 Topic Index Saving Loading and Restoring of EPLCG Data Sequence of Even
32. niversal Station operators and user written programs must be reported back to the EPLCG by the PLC If it is not the operators or user written programs will not be able to see the status changes EPLCG Implementation Guidelines 3 13 9 97 3 3 3 3 3 3 2 Activating Reporting by Exception To activate reporting by exception add two to the port address in the PCnPORT parameter n PLC number 1 through 8 A port address of 1 or 2 specifies that the PLC is connected to ports 1 or 2 respectively and that continuous scanning of the PLCS is configured A port address of 3 or 4 specifies that the PLC is connected to ports 1 or 2 respectively and that reporting by exception from the PLCs is configured RBE message can also be accepted for points which are scanned by EPLCG 3 3 3 3 Addressing Example for Allen Bradley The figure below shows a simple hypothetical system The addresses of the Communication Interface Modules CIM and PLC are in octal notation provided for illustration only Nonredundant EPLCG EPLCI 1 0 Card 21 A Network B Network A EPLCG accesses PLC file 17 decimal matches KE octal address 31 16696 Figure 3 2 Nonredundant EPLCG with Redundant Allen Bradley Communications EPLCG Implementation Guidelines 3 14 9 97 3 3 3 For RBE the PLC must be programmed to detect database changes and send updates to the EPLCG The PL
33. nting Loading Errors EPLCG Data EPLCG and DHP Data Configuration Box Slot Hiway Data Hiway Addresses EPLCG Data Restoration Dependencies Implementation DHP Box Assignment Hiway Address Assignments Effects of Database Composition Point Planning Guidelines Emulated DHP Hiway Address Assignments Entities Hiway and Box Slot Box Slot Hiway EPLCG Functions Redundant Gateways Interboard Links Redundant Communication General Features Additional Features Addressing Example Reporting by Exception in Allen Bradley PLCs Digital Input Status Points Modbus Digital Output Scan Suppression Use of Holding Registers in Modicon PLCs Error Recovery Event Processing Events Sequences of Exception Reporting In Allen Bradley PLCs Factors Limiting Performance FILE ERROR Recovery General Features GE Go NN BP GONE OT OT www ND NU a D D D NO NO NO IO ow N DO ow o oa A NIN ce ha amp D O1 PR Gi NB NIN NOV D nou D ND POLO O CO CN Oo a 00 09 N D9 IO uta w P a En a D w w D D D 6 PONY to to to to Lo amp D D D co a Do BO na ho EPLCG Implementation Guidelines Index 1 9 97 Index Topic Section Heading Hiway Address Emulated DHP 2 5 2 EPLCG 2 5 1 Hiway and Box Slot Entities Building Order Purpose To be Built Hiway Configuration Entities Number Hiway Traffic Director HTD Functions Implementation Dependencies Tasks Summary of Initial Startup or Restart I
34. ntities whose names are reserved for use by the system and begins with a dollar sign The names are in this form SHIWAYnn where nn is the hiway number 01 through 20 2 2 2 Box Slot Entities You must build one box slot entity for each emulated DHP for which you need to build data points Each EPLCG can have up to eight DHPs Like hiway entities box slot entities are reserved entities that is they are entities whose names begin with a dollar sign and are reserved for use by the system The names are in this form HYnnBxx EPLCG Implementation Guidelines 2 1 9 97 2 3 where nn is the hiway number 01 through 20 and xx is the hiway box number 2 and 3 for the EPLCG partners primary and backup and 8 through 15 for the DHPs 2 3 ORDER FOR HIWAY AND BOX SLOT ENTITY BUILDING The order in which the Hiway and Box Slot Configuration activities are accomplished is important To build them select HIWAY GATEWAY on the Engineering Main Menu which calls up the HG Build Type Configuration Menu Then select HIWAY CONFIG to build the hiway entity and BOX SLOT CONFIG to build the box slot entities Do these activities in this order 1 HIWAY CONFIG 2 BOX SLOT CONFIG for this EPLCG pair HG 2 and 3 3 BOX SLOT CONFIG for each DHP in use in this EPLCG pair 8 through 15 NOTE When performing this initial load of a DHP s Box Slot Configuration an A80 Addressing Error will occur To clear th
35. onality s Utilities to check the number of available files and sectors for the EPLCG checkpoint data Use the command s detail d option See Command Processor Operation in the LCN Implementation Engineering Operations 1 binder You can determine if checkpoint data for a specific box is on the medium by using the Utilities List File Attributes LS command to find information for the HGOhhbbr CP file for the box It may be useful to check the time stamps that are in the catalog data to see 1f an incompatible time stamp may be causing a problem For example box data should not be older than EPLCG data 3 2 6 Recovery from DHP Point Configuration Errors Occasionally DHP slot card failures or PC device failures occur due to incorrect point configuration or improper procedure during configuration changes Below is a list of common problems and recovery procedures SYMPTOM DHP slot card failures or PC device errors occur after deleting DHP points or moving points to a different DHP box slot or subslot CAUSE This is often caused by improper deletion of the DHP point before moving it The parameters PCADDRxy SPECIFxy and PCBITxy must be set to zero 0 prior to deleting a DHP point to remove it from the EPLCG scan If this is not done the old point becomes a ghost which continues to be scanned by the EPLCG Such ghost points are saved in the checkpoint file so the only way to remove them is by loading a point to the same DHP box
36. one path fail or become degraded the EPLCG will automatically route traffic through the good port Reconnect timers cause retries every 15 seconds If the problem clears normal routing resumes If both ports are guestionable the EPLCG will route the traffic to both ports for 2 retries If both ports fail the EPLCG will route traffic alternatively between the 2 ports for reconnection attempts EPLCG Implementation Guidelines 3 12 9 97 3 3 2 3 3 2 2 Communication Port Digital Input Status Points The EPLCG provides a total of 11 system visible Digital Input points for monitoring status of the communication ports These points are located in slot 31 of each emulated DHP and are updated once per second Refer to the EPLCG Planning Installation and Serivce manual for details 3 3 2 3 Keep Alive Writes With Allen Bradley protocol and redundant communications selected redundant EPLCGs each have independent access to all PLCs and Keep Alive writes to each PLC can be performed by both EPLCGs simultaneously To provide each PLC with independent Primary Secondary Keep Alive data the primary EPLCG performs Keep Alive writes to the configured word and bit while the secondary EPLCG writes to the configured word but to the configured bit 8 Modulo 16 This causes the Secondary to use the byte opposite to the one used by the Primary If the Primary is configured to use bits 0 7 the Secondary will use bits 8 15 If the Primary is writing
37. parameters include PCADDRxy SPECIFxy and PCBITxy which cause the EPLCG to rebuild the scan table for data acguisition These operations will cause system alarms and may concern operators A method to minimize these alarms during configuration is to load DHP points with the DHP box in the RESET state NOTE Loading multiple DHP points with the DHP box RESET is not recommended for a new DHP database since the point configuration and connection to the PLC device are not checked by the DHP box while in the RESET state Because any bad point could fail the entire slot debugging point configuration errors after Load Multiple is more difficult EPLCG Implementation Guidelines 3 2 9 97 3 2 3 2 LOADING SAVING AND RESTORING OF EPLCG DATA 3 2 1 EPLCG Initial Startup or Restart EPLCGs are loaded with software and data through the Gateways and Interfaces display which is called up through the System Status display On the Gateways and Interfaces display select the node number or pair of node numbers for the EPLCG that is to start up as the primary EPLCG Then select the appropriate node loading targets and follow the prompters to initiate loading of the EPLCG select OPERATOR PROGRAM to load with the operating personality After the status for the primary EPLCG goes to OK you can initiate loading of the backup EPLCG When it is loaded its status becomes BACKUP The EPLCG is loaded with its software personality image and a data image T
38. predetermined time 20 seconds at present the primary will shutdown allowing the backup to take over and provide the system with the better view When this occurs a digital status bit will be set to indicate that the failover was caused by best view Modbus protocol does not allow multiple masters and since EPLCGs must share access to PLCs primary selection by best view cannot be performed in the Modbus redundant communications environment EPLCG Implementation Guidelines 3 16 9 97 3 3 4 3 3 4 Nonredundant Communication to Allen Bradley PLC 5 3 3 4 1 General Information To communicate with an EPLCG the PLC 5 must use the PLC 2 emulation mode with byte addressing Allen Bradley full duplex DF1 protocol is used on an EIA RS 232 C link To communicate with a EPLCG it is recommended that you use an integer file type N Typical implementation involves creation of an intermediate integer file in PLC 5 used only for EPLCG communication All files in the PLC 5 s memory are addressed with a decimal number 9 999 Ladder logic must be implemented to transfer data in the intermediate integer file to and from the appropriate PLC 5 files actually used for PLC 5 processing Performing block moves is one method of transferring data The EPLCG and Allen Bradley full duplex DF1 protocol has no mechanism for specifying a PLC 5 file number Therefore the PLC 5 integer file number must be the decimal equivalent to the octal DH address of
39. stored To accept a load the EPLCG status on the Hiway Status display must be OK The DHP status must be RESET or OK and the box control state must be BASIC When a load is completed successfully the word RESTORED appears adjacent to the box s status indicator EPLCG Implementation Guidelines 3 8 9 97 3 2 5 3 2 5 Recovering from Checkpointing and Loading Errors The following error messages may appear on the Process Networks Node Status display or on the Hiway Status display when you attempt to save EPLCG checkpoint and box checkpoint data when you attempt to load an EPLCG or boxes or when you attempt to save box checkpoint data FILE ERROR See subsection 3 2 5 2 BAD REQUEST A request was made for a box configured as AddedHG or RemoteHG and not ThisHG The EPLCG and all emulated DHPs must be configured as ThisHG CONFLICT The EPLCG is busy with another save or load operation NO VOLUME Either no medium cartridge or floppy is mounted in the drive specified or the volume doesn t exist on the HM or no checkpoint files were found on the specified medium cartridge floppy or HM BAD STATE The box was not in a proper state to accept the command See subsection 3 2 2 the Universal Station from displaying the correct status Some operations might terminate because of an error such as a cartridge or floppy not mounted or a bad medium and a message such as FAIL HGnn appears This doesn
40. t mean the EPLCG failed it s the operation that failed 3 2 5 1 Recommended Actions for Error Recovery 1 Use the SCREEN PRINT function to print a copy of the Gateway Status display or the Hiway Status display If boxes are involved you may need to print more than one display to document both the HG status and box status Check the Real Time Journal print out s on the printer This information will be useful if you need to consult with Honeywell about the problem Error messages that result from these operations are in this form D CP CHKPNT xx yy Zz E 5001 through 5063 where the last two digits are the number of the box that is involved or 60nn where nn is the HG file number or 0 the system crashed Provides a cause of error indication Indicates the internal HG module name 2958 EPLCG Implementation Guidelines 3 9 9 97 3 2 5 3 2 5 2 Recovery from a FILE ERROR AFILE ERROR message is caused by one of the following An attempt to load a box that was not previously checkpointed e Needed checkpoint files were not found on the medium cartridge floppy or HM that was specified A hiway error occurred as access to a box was attempted e Ona SAVE DATA operation the medium was full too few files formatted or the directory was too small to accept the data e An error occurred as access to the medium was attempted You should use the Catalog LS or CAT command in the Engineering Pers
41. ter self tests have completed If a PLCG and an EPLCG are configured as a redundant pair not a legal configuration a Hiway Error is posted and the gateways will not communicate with each other If the PLCG is loaded first the EPLCI will fault red self test LED lit and the EPLCG will not load 3 3 2 Redundant Communication 3 3 2 1 General Features The EPLCG can provide redundant communication paths to the PLC devices If TS3 Pin 2 is configured for redundant communications the two independent communication ports on the EPLCG will be reconfigured by the firmware to provide two alternate paths to the PLC data and the EPLCG will route traffic through whichever port comes ready first Port 2 has a slightly higher priority level so a tickle timer causes Port 1 to be used every 15 seconds Communication redundancy provides two eguivalent paths to a single PLC device address since the EPLCG is unaware of any PLC redundancy schemes Communication is to a single device address and primary backup position is transparent Each PLC of a redundant pair must provide two ports for redundant communication with each port providing access to the same copy of data shared by the redundant PLCs Refer to the EPLCG Planning Installation and Service manual for wiring configuration of redundant communication If redundant communications mode is selected port selection and recovery will be performed without operator or system software intervention Should
42. to bits 8 15 the Secondary will use 0 7 This will allow the PLC programmer to create intelligent fall back or indication schemes as needed Using Modbus protocol the backup EPLCG does not have independent access to the PLCs so only the primary can perform Keep Alive writes 3 3 3 Allen Bradley Communication Redundancy Additional Features 3 3 3 1 Reporting by Exception in Allen Bradley PLCs To reduce the communication load presented to Allen Bradley PLCs by the EPLCG the PLC s exception reporting feature can be used If this option is chosen after the initial PLC data has been scanned by the EPLCG it expects PLCs to notify it of significant changes in the PLC data by sending unsolicited inputs to the EPLCG To avoid undetected loss of communication from the PLCs keep alive PLC addresses and bits must be configured in the box slot entity for the DHP serving each Allen Bradley PLC parameters PCnALIVE AND PCnALVBT where n PLC numbers 1 through 8 If communication of a keep alive bit fails the EPLCG places all points in the target PLC on continuous scan until the data is reestablished and all data points that reference that PLC fail Once communication is reestablished and new values are obtained reporting by exception resumes If this option is chosen the ladder logic program in the PLC must support reporting by exception and must initiate all such reporting Because periodic scanning of the PLC data is not occurring changes by U
43. ts Synchronization Service Site Planning Startup or Restart Subsystem EPLCG Summary of EPLCG Implementation Tasks Synchronization Seguences of Events Tasks Implementation Summary Ten Steps to Start Up an EPLCG The EPLCG Subsystem Use of Holding Registers in Modicon PLCs EPLCG Implementation Guidelines Index 3 Section Heading D D amp w W DR DD D ED ine D TN Cote a a 9 97 EPLCG Implementation Guidelines Index 4 9 97 FAX Transmittal FAX No 602 313 4842 TO G Cacciatore Total FAX pages including this page Reader Comments Title of Document EPLCG Implementation Guidelines Document Number EP12 400 Issue Date 9 97 Commenis FROM Name Date Title Company Address City State ZIP Telephone FAX You may also call 800 822 7673 available in the 48 contiguous states except Arizona in Arizona dial 602 313 5558 or write to Honeywell Inc Industrial Automation and Control Automation College 2820 West Kelton Lane Phoenix AZ 85023 3028 Honeywell Industrial Automation and Control Helping You Control Your World Automation College 2820 W Kelton Lane Phoenix AZ 85023 3028
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