Configuration Manual
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1. Values Yes Route entry checks for Modbus destination address No Route entry enables any Modbus destination address Notes It s generally good to use Modbus address filtering avoiding unnecessary network traffic 2 2 5 Address to Filter Description Comma separated list of the Modbus addresses of slaves behind on this route entry max 20 pcs Values Maximum 20 pcs of comma separated Modbus destination addresses Notes The Filter Slave address parameter of Route entry needs to be enabled these addresses to take effect 2 2 6 Connection Idle Timeout Description If there hasn t been communication on this route during given amount of seconds the Gateway automatically closes the TCP connection to slave and therefore frees Slave s communication resources This is especially useful when multiple Masters access same Slave Values 0 32500 seconds Notes Set this parameter about two times the polling interval of Master 2 2 7 Enable TCP Keepalive Description Defines is the connection testing enabled for TCP network communication Values Enabled Testing the TCP connection with Slave is enabled Disabled Testing the TCP connection with Slave is disabled Notes The testing is done by sending TCP keepalive packets on certain intervals Copyright 2004 Viola Systems Ltd Arctic Modbus Gateway Configuration Manual 3 CONFIGURING2. Notes Check the data bits supported by connected Modbus equipment Generally Modbus RTU communication uses 8 data bits and Modbus ASCII communication uses 7 data bits 2 1 12 Serial Stop Bits Description Defines the number of stop bits used on Modbus serial communications Values 1 2 Notes Copyright 2004 Viola Systems Ltd Arctic Modbus Gateway Configuration Manual 2 1 13 Serial Parity Description Defines the parity method used on Modbus serial communication Values None no parity method used Even even parity bit generated and inspected Odd odd parity bits generated and inspected Notes 2 1 14 Serial Flow Control Description Defines is the hardware RTS CTS flow control used on Modbus serial communication Values Enabled RTS CTS flow control used Disabled RTS CTS flow control not used Notes Use of hardware flow control is suggested 2 1 15 Server TCP UPD Port Description Defines the TCP or UDP port that Masters can form connections to Default Modbus TCP IP communication port is 502 Values 1 32500 Notes If multiple Modbus Gateways are running on same device for both serial ports the TCP UDP communication ports must not be same Use e g ports 502 and 504 The network and Arctic firewalls must enable TCP or UDP communication for that port 2 1 16 Maximum Number of Clients Description Defines how man
3. Arctic waits the response from Modbus slave If the response is not receive Arctic can generate and return Modbus gateway exception Values 0 90 000 000 microseconds 0 90 seconds Notes The reply timeout of Modbus Master must be greater than the Gateway Arctic timeout Otherwise the flow of request reply communication is violated Arctic does not accept a new request before the reply from slave is received or the reply timeout is elapsed The delays in network communication can vary especially in wireless e g GPRS EDGE Mobitex networks When the slaves are located on network side use e g PING to estimate the delay packets spend on network 2 1 6 Inter Frame Timeout Description Defines the idle time in microseconds 10E 6 seconds that marks the end of Modbus frame in serial communication If value is zero the Gateway uses standard 4 character time Values 0 2 000 000 microseconds 0 2 seconds Notes Use as small value as possible to speed up communication and increase the value if problems arise Some PC programs can insert unexpected delays between serial characters 2 1 7 Generate Gateway Exceptions Description Defines does the Gateway generate and return Modbus Gateway exception message to Master if no valid reply is not received from slave Values Enabled Generation of Gateway exceptions is enabled Disabled Generation of Gateway exceptions is disabled Notes This functionality is
4. used prefer UDP based Modbus network messaging Slave response timeout Depends of connected Modbus slave and delays of TCP IP network Increase this value if problems on slave communication Inter frame timeout Modbus RTU protocol has standard timeout of 4 character time Use value 0 for default Increase this value if problems on serial communication Generate Gateway exceptions Enable or Disable Enabling Gateway Exceptions can help system debugging and testing Pass Gateway exceptions Enable or Disable Serial Port Select Port 1 or Port 2 If single serial port or RS 422 485 functionality is required use Port 2 Serial Speed Depends of connected Modbus Master Serial Data Bits Depends of connected Modbus Master Use of Auto selects 8 data bits for Modbus RTU and 7 data bits for Modbus ASCII Serial Stop Bits Depends of connected Modbus Master Serial Parity Depends of connected Modbus Master Select None Even or Odd Serial HW Handshaking Enable if require by Master Server TCP UDP Port Default port for Modbus network communication is 502 Value is not used on Serial Master to Network Slaves mode Max Number of clients Normally use minimum value 2 If multiple Masters are allowed to connect increase the value Value is not used on Serial Master to Network Slaves mode Connection idle timeout Set about two times the polling int
5. 1 Settings The configuration menu is located on Applications Modbus GW menu of Arctic WEB configuration Gateway status Gateway mode g Enabled 7 Disabled Protocols Serial master to network slaves x Serial Protocol Network Protocol Framing ModbusRTU ModbusTCP y Slave response timeout 20000 microseconds Inter frame timeout 0 microseconds specify O as Inter character timeout for automatic 4 character delay time Exceptions Generate Gateway exceptions Yes Y Pass Gateway exceptions Yes v Serial settings sera Porz Speed Data 38400 v Bits Use HW handshaking CTS RTS mode Stopp N Auto v aP 1 v Parity None Y Network server settings only for Network master to serial slaves No Y a TCP UDP 502 Max number of clients 10 Connection idle izo Enable timeout 120 seconds keepalive Apply Yes v Fig 4 2 Example of common parameters for Serial Master to Network Slaves mode Copyright O 2004 Viola Systems Ltd Page 16 Arctic Modbus Gateway Configuration Manual Table 4 1 Setting guideline for Network Master to Serial Slaves mode Parameter Value Note Gateway Status Enabled Gateway Mode Serial Master to Network Slaves Serial Protocol Depends of connected Modbus Master Prefer Modbus RTU when possible Network Protocol Depends of Slave devices If Viola Systems M2M tunneling is
6. 2 7 Enable TCP KeepallVes cda lost plana DIRE rana bal Nela 11 3 CONFIGURING NETWORK MASTER TO SERIAL SLAVES MODE ocoocccnccnccnnccnnccncccnnnnnnonnrinancnnnnnos 12 3 1 Settings COMMON PAaraMetelS cece e eee eee eee eee tntto tts ence eee a eect een ee sateen ee aaeeeaee 13 3 2 Saving Para Mete Scan ts 14 4 CONFIGURING SERIAL MASTER TO NETWORK SLAVES MODE oooccccccccnnccncccnnoncnnnncncnnnccncnnnnnanos 15 4 1 Settings Common ParametelS 0c eee ee en eee tees eee aaeeaaeeeaies 16 4 1 1 Saving COMMON ParaMetelS ccc een eee e reed e ed eee dee ean esate aeeenes 17 42 Settings ROQUES A A PERETE ANAT RE A a 18 A 2 SAVING RUS ao 19 4 3 Making Settings PerManent ct eee ee eee teen eran eeeaiees 19 Copyright 2004 Viola Systems Ltd Page 4 Arctic Modbus Gateway Configuration Manual 1 INTRODUCTION This Configuration guide is intended only for configuring Modbus on Viola Arctic device It therefore presents only Modbus specific functionality If you need to know more about general Arctic configuration please refer to Arctic User s Manual This User s Manual should be shipped with Arctic products or it could be obtained by contacting Viola Systems The Modbus Gateway is an adapter application enabling conversions between Serial and Network Modbus protocols The gateway can operate on two modes either connecting serial Masters to Slaves behind the network or connecting network Master to Ser
7. ALA systems Arctic Modbus Gateway Configuration Manual Arctic Modbus Gateway Configuration Manual Copyright and Trademark Copyright 2004 Viola Systems Ltd All rights to this manual are owned solely by Viola Systems Ltd referred in this manual as Viola Systems All rights reserved No part of the contents of this manual may be transmitted or reproduced in any form or by any means without the written permission of Viola Systems Ethernet is a trademark of XEROX Corporation Windows and Internet Explorer are trademarks of Microsoft Corporation Netscape is a trademark of Netscape Communications Corporation Linux is a Registered Trademark of Linus Torvalds All other product names used in this manual are the properties of their respective owners and are acknowledged Viola Systems Ltd Lemminkaisenkatu 32 FIN 20520 Turku Finland Technical Support Phone 358 0 20 1226 226 Fax 358 0 20 1226 220 E mail support violasystems com On line http www violasystems com Copyright 2004 Viola Systems Ltd Page 2 Arctic Modbus Gateway Configuration Manual Disclaimer Viola Systems reserves the right to change the technical specifications or functions of its products or to discontinue the manufacture of any of its products or to discontinue the support of any of its products without any written announcement and urges its customers to ensure that the information at their disposal is valid Viola software
8. NETWORK MASTER TO SERIAL SLAVES MODE When the PLC RTU slaves supporting serial based Modbus communication are required to be controlled over TCP IP networks the Gateway on slave side needs to be configured to Network Master Serial Slaves mode TOPP Network Fig 3 1 Arctic Modbus Gateway connecting serial slaves to network On that mode the Arctic Modbus Gateway acts like network server where Masters clients can connect the default port being 502 and transmit Modbus requests The Gateway makes conversions between network and serial protocols If the slave does not reply during defined timeout or if the reply is corrupted the Gateway sends gateway exception message back to Master if the exception generation is enabled Otherwise the reply is returned Multiple masters can connect simultaneously to Gateway which handles the multiplexing between masters NOTE Each Arctic Modbus Gateway must have a fixed IP address in order the Master tg know where to connect Many client use optimized networks like public GPRS xDSL does not offer fixed IP addresses but allocate them dynamically This situation can be solved by using Viola Systems M2M Gateway Copyright 2004 Viola Systems Ltd Page 12 Arctic Modbus Gateway Configuration Manual 3 1 Settings Common parameters Only the common parameters are configured The routes are unused on Network Master to Serial Slaves mode The configuration menu is located o
9. and programs are delivered as is The manufacturer does not grant any kind of warranty including guarantees on suitability and applicability to a certain application Under no circumstances is the manufacturer or the developer of a program responsible for any possible damages caused by the use of a program The names of the programs as well as all copyrights relating to the programs are sole property of Viola Systems Any transfer licensing to a third party leasing renting transportation copying editing translating modifying into another programming language or reverse engineering for any intent is forbidden without the written consent of Viola Systems Viola Systems has attempted to verify all information in this manual as of the publication date We assume no responsibility for any errors that may appear in this guide Information in this manual may change without prior notice from Viola Systems Copyright 2004 Viola Systems Ltd Page 3 Arctic Modbus Gateway Configuration Manual Tableof Contents T INTRODUCTION siesteie tree oxo vneeviiensnedy candace Coen dey deh E AEEA EE ten caene ed heen dee pevts aa 5 2A PARAMETERS dai na 6 2 COMMON PAM Sii A A ed 6 21 1 Gateway SAUS A A A aN Aa a A ANA VEAN 6 2 1 2 Gateway Mode iive yn dd daa 6 2 1 3 Serial Protocol ida e EEE tae teens ee Aaa 6 2 1 4 NetWork Protocol rr e a AAAA Aka Aa a ia ni 7 2 1 5 Slave Response TiMeQUt occoocccncccnnccnncccncinnnnnnncnoncnnnnn
10. bling more efficient communication where each slave receives only data addressed to it 2 2 1 Route in Use Description Defines is this route entry used to decide to which IP address Modbus request is sent Values Yes Route information is used No Route information is not used Notes If no route is found for Modbus request is it dropped and Gateway exception is generated if enabled 2 2 2 Host Description Defines the IP address or Host name where packets are routed by that entry Values IP address or Host name Notes If Host names are used the DNS server IP address is required to be defined on Arctic Network settings The Network Protocol setting on Common parameters defines the network and Modbus protocol used on network communication 2 2 3 TCP or UDP Destination Port Description Defines the UDP or TCP destination port where this route entry sends Modbus requests Values 0 32500 Modbus default is 502 Notes The port must be same as used on the network slave device or Gateway behind network Copyright 2004 Viola Systems Ltd Page 10 Arctic Modbus Gateway Configuration Manual 2 2 4 Filter Slave Address Description Defines is the routing based on Modbus addresses used for that entry If not enabled every Modbus request is routed to this entry If enabled only Modbus requests having destination address matching the Address list of entry are routed
11. ctive routes do not have strikethrough line Pressing the Edit button opens following configuration screen Edit route 1 Route in use Yes vij Host name or IP address 172 16 200 12 TCP or UDP destination port 502 Filter slave addresses Yes Addresses to filter 1 2 Connection idle timeout TCP 120 vac EN Enable TCP keepalive Yes v Fig 4 4 Route edit Copyright O 2004 Viola Systems Ltd Page 18 Arctic Modbus Gateway Configuration Manual Table 4 2 Setting guidelines for routes Parameter Value Note Route in use Enable or Disable Each IP address and TCP UDP port of slaves needs to be defined on separate route entries Host The IP address or Host name of slave If Host names are used the DNS server IP or Gateway behind the route address is required to be defined on Arctic Network settings The Network Protocol setting on Common parameters defines the network and Modbus protocol used on network communication TCP or UDP destination The TCP or UDP port that slave or Default Modbus port is 502 port Gateway on slave side is listening Filter slave addresses Defines is the routing based on It s generally good to use routing based Modbus addresses used for that entry on Modbus addressing in order to avoid If not enabled every Modbus request is unnecessary network traffic routed to this entry If enabled only Modbus requests having destination address matching the Addr
12. ds of connected Modbus slave Increase this value if problems on serial communication Inter frame timeout Modbus RTU protocol has standard timeout of 4 character time Use value 0 for default Increase this value if problems on serial communication Generate Gateway exceptions Enable or Disable Enabling Gateway Exceptions can help system debugging and testing Pass Gateway exceptions Enable or Disable Serial Port Select Port 1 or Port 2 If single serial port or RS 422 485 functionality is required use Port 2 Serial Speed Depends of connected Modbus slave Serial Data Bits Depends of connected Modbus slave Use of Auto selects 8 data bits for Modbus RTU and 7 data bits for Modbus ASCII Serial Stop Bits Depends of connected Modbus slave Serial Parity Depends of connected Modbus slave Select None Even or Odd Serial HW Handshaking Enable if require by slave Server TCP UDP Port Default port for Modbus network communication is 502 If multiple Modbus Gateway applications are running on same Arctic the ports must be different for each Gateway application Use e g ports 502 and 504 Max Number of clients Normally use minimum value 2 If multiple Masters are allowed to connect increase the value If the network is wireless or unreliable increase this value if problems on connection forming Connection idle timeout Set about two time
13. erval of Master If the polling interval is very long over hour use e g polling interval 200 seconds Value is not used on Serial Master to Network Slaves mode Each route entry has it s own idle timeout Enable keepalive Enable if the polling interval or idle timeout is very long Value is not used on Serial Master to Network Slaves mode Each route entry has it s own keepalive setting 4 1 1 Saving Common Parameters Before proceeding to Route configuration save the Common parameters by pressing the Apply button Copyright O 2004 Viola Systems Ltd Page 17 Arctic Modbus Gateway Configuration Manual 4 2 Settings Routes The route entries define how Modbus packets are routed on network from Serial Master to Network Slaves Up to 30 routes can be specified each having up to 20 slaves If the routing based on Modbus addressing is not required or there is more than 20 slaves behind the route the address filtering for that entry can be disabled Routes to client slaves only for Serial master to network slaves mode ID Host Port Filter Slaves Idle timeout Keepalive 1 172 16 200 12 502 Yes 1 2 120 Yes K ra 2 amp 666 563 Yes 120 Yes 3 00048 8 No 8 8 He Fig 4 3 Route summary The route entry can be edited by pressing Edit button The routes can also be disabled or enabled by pressing following buttons E E Disables the Route entry Enables the Route Entry The a
14. ess list of entry are routed Address to filter Comma separated list max 20 pcs of The Filter Slave address parameter of Modbus slave addresses behind this Route entry needs to be enabled these route entry addresses to take effect Connection idle timeout Set about two times the polling interval TCP of Master If the polling interval is very long over hour use e g polling interval 200 seconds Enable TCP keepalive Enable if the polling interval or idle timeout is very long 4 2 1 Saving Routes When parameters are configured press the Route Ready button and proceed to next route 4 3 Making Settings Permanent When all Routes and Common settings are configured permanently store the parameters by Commit button and reboot the Arctic Modbus Gateway The Arctic is now ready to deliver data from serial Masters to network Slaves Copyright 2004 Viola Systems Ltd Page 19
15. ial slaves The gateway offers following core properties Supports Modbus RTU and Modbus ASCII serial protocols Supports ModbusTCP ModbusRTU over TCP ModbusRTU over UDP Modbus ASCII over TCP and Modbus ASCII over UDP network protocols Can generate and filter out gateway exceptions Can route traffic on network based on Modbus addressing enabling intelligent use of network resources Makes automatic connection management Enables multiple server sessions over network e Offers unlimited amount of Masters on serial or Network side e Offers 30 routes over network to slaves Copyright 2004 Viola Systems Ltd Page 5 Arctic Modbus Gateway Configuration Manual 2 PARAMETERS The parameters are divided on two groups e Common parameters e Routes Common parameters define e g the protocols used in serial and network communications serial port settings and protocol specific timeouts Route parameters are only required on Serial Master to Network Slaves mode defining the IP and Modbus addresses of slaves behind the network 2 1 Common parameters The common parameters define general settings and settings for Network Master to Serial Slaves mode 2 1 1 Gateway Status Description Defines is the Modbus gateway functionality enabled for the serial port Values Enabled Modbus Gateway is enabled Disabled Modbus Gateway is not enabled Notes Each serial port of Arctic has it s own Modbus Gateway definitio
16. n Applications Modbus GW menu of Arctic WEB configuration ModBus Gateway 1 Settings g Enabled Gateway status C Disabled Gateway mode Network master to serial slaves Y Protocols Serial Protocol ModbusRTU Y Network Protocol ModbusTCP vw Framing Slave response timeout 20000 microseconds Inter frame timeout O microseconds specify O as Inter character timeout for automatic 4 character delay time Exceptions Generate Gateway exceptions Yes x Pass Gateway exceptions Yes v Serial settings senal Poezi Speed 38400 Vips Auto v Sker 1 MParity None Use HW handshaking CTS RTS No v Network server settings only for Network master to serial slaves mode root tal TCP UDP ag Max number of clients 10 _ Connestionidle iapTTIseconds MMe es oriy Reset Fig 3 2 Example of common parameters for Network Master to Serial Slaves mode Copyright 2004 Viola Systems Ltd Page 13 Arctic Modbus Gateway Configuration Manual Table 3 1 Setting guideline for Network Master to Serial Slaves mode Parameter Value Note Gateway Status Enabled Gateway Mode Network Master to Serial Slaves Serial Protocol Depends of connected Modbus slave Prefer Modbus RTU when possible Network Protocol Depends of Master side If Viola Systems M2M tunneling is used prefer UDP based Modbus network messaging Slave response timeout Depen
17. nnnrrnnnnnnrnnnrannrnnnnrrnnrrnnrrnnnnnnarenanens 7 2 1 6 Inter Frame THMeOUty a ecescee sees cece cees E A ys eevee eaeg di 7 2 1 7 Generate Gateway Exceptions 0 e cece eee eee eee eee e een ees eea een ease tesa eeseteaeeeaeee 2 1 8 Pass Gateway Exceptions raens na a ana a a eii ae aa aA aA ane a FAEN 7 2 1 9 Serial Polla a dado a aAa 8 2 12 10 Serial Speed oian ri ea aieiaa e i aA oa EAEE AENEA ELETA E T ETA race 8 2 111 SertallData BitSsann entane toes R oa E A E EA 8 2 412 Se al Stop Bits aiaa a A TE aa A adi s 8 212135 Serlal Parity ie a Aa A aeaa ae 8 21 14 Seral Flow Control aaau ete NEKA A ands etd aeons Glad et aed at lea cote 9 2 1 15 Server TEP UPD POM reisinin tice nena A A a Eder A A 9 2 1 16 Maximum Number of ClientS oooocccncccnccncccnncnnncnnncnnnncnnnccnnconnncnnnnnnnnnnconnnnoncnnnccnncnnnes 9 2 1 17 Connection Idle TiMeQUt oocoonccncccncccncinnccnnccnnncncnnnnonnnnnncnnnnnnrnnnnnnnnrnnrennnnnrrnnrrnnceninns 9 2 1 18 Enable Keepallive 0 eee an reer sane AEA Ea KEEA 9 22y ROUTES ann raen Saas do 10 22l ROUTE M USE a a a a a E tees a e a Era ae ees 10 DUD DQ OA T O A 10 2 2 3 TCP or UDP Destination Port 0c ee te eee aa a Aaa Aaaa aaa aa 10 2 2 4 Filt rSlave AGdress henin anran ed ed raved od 10 2 2 5 Address to Filter a Aa ai AAEN aSa iaae 11 2 2 6 Connection Idle TiMeQUt oocccoccncccncccnccnncnnncnnnconcnnnrnnnnnnnnnnnncnnrnnrnnnrrnnnnnrannnennnenaneninns 11 2
18. ns 2 1 2 Gateway Mode Description Defines are the slaves located on network or serial side Values Network Master to Serial Slaves Slaves are on serial side Serial Master to Network Slaves Slaves are on network side Notes If slaves are on network side also routes are needed to be defined 2 1 3 Serial Protocol Description Defines the Modbus protocol used on serial communication Values Modbus RTU Serial devices use Modbus RTU protocol Modbus ASCII Serial devices use Modbus ASCII protocol Notes Modbus RTU is more efficient and should be used whenever possible Copyright 2004 Viola Systems Ltd Page 6 Arctic Modbus Gateway Configuration Manual 2 1 4 Network Protocol Description Defines the TCP IP and Modbus protocol used on network communication Values Modbus TCP Modbus TCP protocol over TCP Modbus RTU over TCP Modbus RTU protocol over TCP Modbus RTU over UDP Modbus RTU protocol over UDP Modbus ASCII over TCP Modbus ASCII protocol over TCP Modbus ASCII over UDP Modbus ASCII protocol over UDP Notes If Viola Systems M2M Gateway is used to tunnel network traffic over SSH use Modbus RTU over UDP when possible for efficient communication The SSH tunnel already contains TCP properties like reliable message delivery 2 1 5 Slave Response Timeout Description Defines the time in microseconds 10E 6 seconds how long
19. s the polling interval of Master If the polling interval is very long over hour use e g polling interval 200 seconds Enable keepalive Enable if the polling interval or idle timeout is very long 3 2 Saving Parameters When settings are complete press the Apply button permanently store the parameters by Commit button and reboot the Arctic by pressing Reboot button The Arctic is now ready to deliver data from Network Masters to Serial Slaves Copyright O 2004 Viola Systems Ltd Page 14 Arctic Modbus Gateway Configuration Manual 4 CONFIGURING SERIAL MASTER TO NETWORK SLAVES MODE When Modbus Master supporting serial based Modbus communication needs to control slaves over TCP IP network the Gateway on Master side needs to be configured to Serial Master Network Slaves mode TCP IP Network PLC Modbus slaves Fig 4 1 Arctic Modbus Gateway connecting serial Master to network On that mode Arctic Modbus Gateway routes serial Modbus packets to network and performs conversions between serial and network protocols The routing based on Modbus addressing allows intelligent use of network resources which is especially useful for pay per use networks like GPRS The settings consist of two parts e Common settings e Settings for each route Copyright 2004 Viola Systems Ltd Page 15 Arctic Modbus Gateway 4 1 Settings Common Parameters Configuration Manual ModBus Gateway
20. useful for debugging See also parameter Pass Gateway exceptions Copyright 2004 Viola Systems Ltd Arctic Modbus Gateway Configuration Manual 2 1 8 Pass Gateway Exceptions Description Defines are the Gateway exception replies from slave side passed to master Values Enabled Gateway exception replies are passed to Master Disabled Gateway exception replies are filtered away Notes This functionality is useful for debugging 2 1 9 Serial Port Description Defines the serial port that Gateway uses for Modbus serial communication Values Port 1 Serial port 1 RS 232 console application port Port 2 Serial port 2 RS 232 422 485 application port Notes If single serial port or RS 422 485 is required use Port 2 If Port 1 is used the console switch of Arctic must be on Application position DIP switches below the DB 9 serial connector specify the RS 232 422 485 settings of Port 2 2 1 10 Serial Speed Description Defines the serial port speed for Modbus communication Values 300 1200 2400 4800 9600 19200 38400 57600 115200 bps Notes Check the speeds supported by connected Modbus equipment If special serial port speed is required please contact Viola Systems 2 1 11 Serial Data Bits Description Defines the number of data bits used on Modbus serial communications Values 5 6 7 8 Auto 8 for Modbus RTU 7 for Modbus ASCII
21. y network masters can be connected to Gateway simultaneously Values 0 20 Notes Generally use value at least 2 when using TCP communication Otherwise if the Gateway does not recognize partially closed connection forming of new connections is not accepted by Gateway before Connection idle timeout is elapsed 2 1 17 Connection Idle Timeout Description If the connected Master hasn t sent valid Modbus packets during that timeout the connection is closed by Arctic and therefore the resources are available for new connections This parameter is especially useful when the network connection is not reliable causing hanging or partially closed connections Values 0 32500 seconds Notes Set this value about two times the polling interval of master Copyright 2004 Viola Systems Ltd Page 9 Arctic Modbus Gateway Configuration Manual 2 1 18 Enable Keepalive Description Defines is the connection testing enabled for TCP network communication Values Enabled Testing the TCP connection with Master is enabled Disabled Testing the TCP connection with Master is disabled Notes The testing is done by sending TCP keepalive packets on certain intervals 2 2 Routes When the Arctic Modbus Gateway is configured to Serial Master to Network Slaves mode the routes are needed to be defined for each connected Modbus slave Gateway can route traffic based on Modbus addressing therefore ena
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