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Network Troubleshooting Network Troubleshooting Presented by: Presented by: Gordon MacLachlan (Mac) Gordon MacLachlan (Mac)

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Page 1: Network Troubleshooting Network Troubleshooting

Network TroubleshootingNetwork Troubleshooting

Presented by:Presented by:Gordon MacLachlan (Mac)Gordon MacLachlan (Mac)

Page 2: Network Troubleshooting Network Troubleshooting

Presentation HighlightsPresentation Highlights

Troubleshooting tools that workTroubleshooting tools that workCommon wiring problems Common wiring problems Common networking problems Common networking problems Common communication problemsCommon communication problemsCommon configuration problemsCommon configuration problemsCommon data transfer problemsCommon data transfer problems

Page 3: Network Troubleshooting Network Troubleshooting

Typical network commissioning Typical network commissioning process:process:1.1. Install the equipmentInstall the equipment2.2. Wire up the networksWire up the networks3.3. Configure equipmentConfigure equipment4.4. Establish communication Establish communication

links between equipmentlinks between equipment5.5. Check communication Check communication

qualityquality6.6. Check data transferCheck data transfer

Page 4: Network Troubleshooting Network Troubleshooting

WhatWhat’’s in your toolbox?s in your toolbox? Troubleshooting tools that work:Troubleshooting tools that work:

Essentials:Essentials:MultimeterMultimeterRSRS--232 Tester (Breakout box)232 Tester (Breakout box)Cell phoneCell phoneInternetInternetEthernet Crossover cableEthernet Crossover cableSerial capture utilitySerial capture utilityEthernet capture utilityEthernet capture utility

Also useful:Also useful:HubHubOscilloscope (for noisy networks).Oscilloscope (for noisy networks).

Page 5: Network Troubleshooting Network Troubleshooting

Common Wiring ProblemsCommon Wiring Problems RSRS--232232::

Receive/Transmit PolarityReceive/Transmit PolarityGround potential differences.Ground potential differences.DTR/DSR and CTS/RTS issuesDTR/DSR and CTS/RTS issuesCable LengthCable Length

Page 6: Network Troubleshooting Network Troubleshooting

Common Wiring ProblemsCommon Wiring Problems RSRS--232 Receive/Transmit Polarity:232 Receive/Transmit Polarity:

Best way to check Polarity is to use a RSBest way to check Polarity is to use a RS--232 Test box 232 Test box (FieldServer supplies a mini(FieldServer supplies a mini--tester)tester)•• With no communications, RD must be on solid.With no communications, RD must be on solid.•• If the same light is on solid (RD or TD) when either side of If the same light is on solid (RD or TD) when either side of

the test box is connected on its own, then the polarity is the test box is connected on its own, then the polarity is wrong.wrong.

A Voltmeter can be used to check a devices pins when it is A Voltmeter can be used to check a devices pins when it is disconnected. Receive will have a zero voltage, Transmit will disconnected. Receive will have a zero voltage, Transmit will have a negative voltage of have a negative voltage of --5to5to--12V (wrt ground).12V (wrt ground).Remember: Rx goes to Tx, and vice versaRemember: Rx goes to Tx, and vice versa

Page 7: Network Troubleshooting Network Troubleshooting

Common Wiring ProblemsCommon Wiring Problems RSRS--232 ground potential differences:232 ground potential differences:

Since signal ground is connected through the Since signal ground is connected through the GND pin, any serious potential differences GND pin, any serious potential differences between the two devices can cause between the two devices can cause communications problems or even interfere communications problems or even interfere with the operation of the device.with the operation of the device.In the rare cases where this is genuinely a In the rare cases where this is genuinely a problem, use an optical isolator to separate problem, use an optical isolator to separate the wiring. Optical Isolators the wiring. Optical Isolators are offare off--thethe--shelf items shelf items that can be purchased online.that can be purchased online.

Page 8: Network Troubleshooting Network Troubleshooting

Common Wiring ProblemsCommon Wiring Problems RSRS--232 DTR/DSR and CTS/RTS issues:232 DTR/DSR and CTS/RTS issues:

NB:NB: FieldServer does not FieldServer does not require DTR/DSR or CTS/RTS require DTR/DSR or CTS/RTS handshaking lines. FieldServer handshaking lines. FieldServer needs Tx/Rx/GND only.needs Tx/Rx/GND only.The device connecting to the The device connecting to the FieldServer may need FieldServer may need handshaking. Solve this by handshaking. Solve this by bridging CTS to RTS (and/or bridging CTS to RTS (and/or DTR to DSR) in the connector DTR to DSR) in the connector connected to the device.connected to the device.

Page 9: Network Troubleshooting Network Troubleshooting

Common Wiring ProblemsCommon Wiring Problems RSRS--232 Cable Length:232 Cable Length:

Maximum recommended cable Maximum recommended cable length for RSlength for RS--232 is 50ft. This is 232 is 50ft. This is conservative if you are using conservative if you are using 18 AWG.18 AWG.Symptoms for cable length problems Symptoms for cable length problems are that communications is noisy. It are that communications is noisy. It is unlikely that a cable that is a is unlikely that a cable that is a bit too long will prevent bit too long will prevent communications completely.communications completely.

Page 10: Network Troubleshooting Network Troubleshooting

Common Wiring ProblemsCommon Wiring Problems RSRS--485485::

+/+/-- PolarityPolarityLine Biasing.Line Biasing.44--wire vs. 2wire vs. 2--wirewireCable LengthCable Length

Page 11: Network Troubleshooting Network Troubleshooting

Common Wiring ProblemsCommon Wiring Problems RSRS--485 Polarity:485 Polarity:

Unlike RSUnlike RS--232 where Tx and Rx cross 232 where Tx and Rx cross over, you connect + to +, and over, you connect + to +, and –– to to –– in in RSRS--485485Some devices use A and B instead of + Some devices use A and B instead of + and and –– labels. Here A is the same as labels. Here A is the same as --, and , and B is the same as +B is the same as +

Page 12: Network Troubleshooting Network Troubleshooting

Common Wiring ProblemsCommon Wiring Problems RSRS--485 Line Biasing:485 Line Biasing:

Literature on RSLiterature on RS--485 guidelines 485 guidelines advises that 120 ohm terminating advises that 120 ohm terminating resistors are applied at the end resistors are applied at the end nodes of an RSnodes of an RS--485 segment. This 485 segment. This is a is a guidelineguideline, and not a rule. , and not a rule. Networks <100 feet usually donNetworks <100 feet usually don’’t need t need terminating resistors.terminating resistors.Line Biasing is achieved with the 120 ohm Line Biasing is achieved with the 120 ohm resistors plus 10kOhm resistors between resistors plus 10kOhm resistors between the signal and ground/5V.the signal and ground/5V.

Page 13: Network Troubleshooting Network Troubleshooting

Common Wiring ProblemsCommon Wiring Problems RSRS--485 4485 4--wire vs. 2wire vs. 2--wire:wire:FieldServer supports 2FieldServer supports 2--wire RSwire RS--485 communications, which 485 communications, which is half duplex RSis half duplex RS--485 and is the more common format found 485 and is the more common format found in industry.in industry.

44--wire RSwire RS--485 (or RS485 (or RS--422) is full duplex RS422) is full duplex RS--485. Some 4485. Some 4--wire RSwire RS--485 will allow you to connect to a 2485 will allow you to connect to a 2--wire RSwire RS--485 485 setup by bridging the Rx and Tx lines to make 2 wires out of setup by bridging the Rx and Tx lines to make 2 wires out of 4. These devices tolerate the visibility of Tx signals on their 4. These devices tolerate the visibility of Tx signals on their Rx lines. However, other 4Rx lines. However, other 4--wire devices do not tolerate this.wire devices do not tolerate this.

It is always possible to connect 2It is always possible to connect 2--wire to 4wire to 4--wire RSwire RS--485 by 485 by using a 2using a 2--4 wire RS4 wire RS--485 converter which is commercially 485 converter which is commercially available.available.

Page 14: Network Troubleshooting Network Troubleshooting

Common Wiring ProblemsCommon Wiring Problems RSRS--485 Cable Length:485 Cable Length:

Recommended maximum length Recommended maximum length is 4000 ft, with no more than 32 is 4000 ft, with no more than 32 nodes connected. This estimate is nodes connected. This estimate is for the most part optimistic.for the most part optimistic.Many factors can reduce the Many factors can reduce the maximum permissible length on maximum permissible length on an RSan RS--485 network, including 485 network, including wire gauge, installation wire gauge, installation environment, and vendor environment, and vendor equipment characteristics.equipment characteristics.When running cable lengths close When running cable lengths close to the recommended maximum to the recommended maximum parameters, keep an RSparameters, keep an RS--485 485 repeater handy just in caserepeater handy just in case……

Page 15: Network Troubleshooting Network Troubleshooting

Common Wiring ProblemsCommon Wiring Problems EthernetEthernet::

Cable qualityCable qualityDirect vs. Crossover.Direct vs. Crossover.

Page 16: Network Troubleshooting Network Troubleshooting

Common Wiring ProblemsCommon Wiring Problems Ethernet Cable Quality:Ethernet Cable Quality:

Most common Ethernet cable in Most common Ethernet cable in use today is CATuse today is CAT--5 UDP cable.5 UDP cable.Using CATUsing CAT--5 UDP has many 5 UDP has many advantages, but the one common problem advantages, but the one common problem experienced is assembly quality. Factory experienced is assembly quality. Factory made cables are usually premade cables are usually pre--tested and tested and tend to work, but cable crimped on site tend to work, but cable crimped on site often leads to problems that are not often leads to problems that are not immediately obvious. immediately obvious.

Page 17: Network Troubleshooting Network Troubleshooting

Common Wiring ProblemsCommon Wiring Problems Ethernet Direct Cable vs. Crossover cable:Ethernet Direct Cable vs. Crossover cable:Use Direct Cable when Use Direct Cable when connecting to a hubconnecting to a hubUse Crossover cable when Use Crossover cable when connecting directly between connecting directly between two devicestwo devicesCables can be differentiated by Cables can be differentiated by looking at the connectors on looking at the connectors on each end of the cable. Hold each end of the cable. Hold them together, facing the them together, facing the same way (e.g.: both clips same way (e.g.: both clips facing away from you). If the facing away from you). If the wire colors follow the same wire colors follow the same pattern on both connectors, pattern on both connectors, then it is a direct cable.then it is a direct cable.

Page 18: Network Troubleshooting Network Troubleshooting

Common Networking ProblemsCommon Networking Problems RSRS--232 & RS232 & RS--485:485:

Baud RateBaud RateMaster vs. Slave.Master vs. Slave.HandshakingHandshakingAddressingAddressingPoll timingPoll timing

Page 19: Network Troubleshooting Network Troubleshooting

Common Networking ProblemsCommon Networking Problems RSRS--232 & RS232 & RS--485:485:Baud RateBaud Rate•• DonDon’’t just check Baud Rate. Check Parity, Data Bits and t just check Baud Rate. Check Parity, Data Bits and

Stop bits too.Stop bits too.•• All devices on the same RSAll devices on the same RS--485 network need to 485 network need to

communicate at the same baud rate. Make sure this is communicate at the same baud rate. Make sure this is possible.possible.

Master vs. Slave.Master vs. Slave.•• For Master/Slave networks (e.g.: Modbus, Metasys), one For Master/Slave networks (e.g.: Modbus, Metasys), one

Master usually controls all communicationsMaster usually controls all communications•• Make sure you know who is master, and that you are not Make sure you know who is master, and that you are not

attempting Masterattempting Master--Master or SlaveMaster or Slave--Slave communications.Slave communications.

Page 20: Network Troubleshooting Network Troubleshooting

Common Networking ProblemsCommon Networking Problems RSRS--232 & RS232 & RS--485:485:

HandshakingHandshaking•• Some Some

devices/protocols devices/protocols demand startup demand startup handshaking like the handshaking like the passing of passwords passing of passwords and device and device information. information.

•• Check literature for Check literature for requirements and requirements and default passwords.default passwords.

Page 21: Network Troubleshooting Network Troubleshooting

Common Networking ProblemsCommon Networking Problems RSRS--232 & RS232 & RS--485:485:

AddressingAddressing•• Make sure the correct device Make sure the correct device

address is being used. This is not address is being used. This is not always obvious (e.g.: BACnet always obvious (e.g.: BACnet MSTP)MSTP)

•• Server devices almost always need Server devices almost always need addresses, but sometimes you need addresses, but sometimes you need to configure client addresses too to configure client addresses too (e.g.: DNP 3.0)(e.g.: DNP 3.0)

•• Some protocols may demand Some protocols may demand address paths or addresses at address paths or addresses at multiple levels (e.g.: Modbus +, multiple levels (e.g.: Modbus +, McQuay)McQuay)

Page 22: Network Troubleshooting Network Troubleshooting

Common Networking ProblemsCommon Networking Problems RSRS--232 & RS232 & RS--485:485:Poll timingPoll timing•• Timing can be a very complicated issue and is Timing can be a very complicated issue and is

not uncommon as a cause for poor not uncommon as a cause for poor communicationscommunications

•• There are many timing factors to be aware of There are many timing factors to be aware of in a communications session (e.g.: Timeouts, in a communications session (e.g.: Timeouts, poll delay, retry intervals, scan intervals, poll delay, retry intervals, scan intervals, probation delays, Inter character timing, etc)probation delays, Inter character timing, etc)

•• Enote067 is very helpful in Enote067 is very helpful in helping understand how helping understand how these parameters interactthese parameters interact

•• Symptoms of a timing Symptoms of a timing problem are usually problem are usually related to the presence related to the presence of partial communicationsof partial communications

Page 23: Network Troubleshooting Network Troubleshooting

Common Networking ProblemsCommon Networking Problems EthernetEthernet::

Subnets and gatewaysSubnets and gatewaysFirewalls.Firewalls.PortsPortsAddressingAddressing

Page 24: Network Troubleshooting Network Troubleshooting

Common Networking ProblemsCommon Networking Problems Ethernet:Ethernet:

Subnets and gatewaysSubnets and gateways•• A common problem in Ethernet is that IP A common problem in Ethernet is that IP

addresses get set up correctly without addresses get set up correctly without the subnets and/or gateway addresses the subnets and/or gateway addresses being set up correctlybeing set up correctly

•• Protocols differ in their Protocols differ in their IP/Subnet/gateway IP/Subnet/gateway requirements, so be requirements, so be aware of the aware of the requirements for the requirements for the separate protocols.separate protocols.

Page 25: Network Troubleshooting Network Troubleshooting

Common Networking ProblemsCommon Networking Problems Ethernet:Ethernet:

Firewalls.Firewalls.•• The thing about firewalls The thing about firewalls

are that they are invisible are that they are invisible to the installer, but can to the installer, but can stop communications in a stop communications in a heartbeatheartbeat

•• Work with the Systems Work with the Systems Administrator to ensure Administrator to ensure that all necessary holes are that all necessary holes are made in the firewalls for made in the firewalls for the application, and that the application, and that the network design is the network design is compatible with the compatible with the companycompany’’s security policies.s security policies.

Page 26: Network Troubleshooting Network Troubleshooting

Common Networking ProblemsCommon Networking Problems Ethernet:Ethernet:PortsPorts•• Be aware that Ethernet protocols have ports too. Be aware that Ethernet protocols have ports too.

However, they are logical, not physical. Be aware of the However, they are logical, not physical. Be aware of the port required for a given protocol, you may need to port required for a given protocol, you may need to open a hole in a firewall for that port.open a hole in a firewall for that port.

AddressingAddressing•• Not all Ethernet protocols use IP addresses for Not all Ethernet protocols use IP addresses for

addressing. Look out for the need to use multiple or addressing. Look out for the need to use multiple or indirect addresses (e.g.: BACnet IP, indirect addresses (e.g.: BACnet IP, Modbus/TCP), Modbus/TCP), or even MAC addresses or even MAC addresses (e.g.: BACnet Ethernet)(e.g.: BACnet Ethernet)

Page 27: Network Troubleshooting Network Troubleshooting

Common Networking ProblemsCommon Networking Problems Ethernet:Ethernet:

System AdministrationSystem Administration•• When adding devices to an When adding devices to an

existing network, be aware existing network, be aware that this cannot be done that this cannot be done without knowledge of what without knowledge of what exists on the network.exists on the network.

•• When doing a new network, When doing a new network, leave a good document trail leave a good document trail of how the network has of how the network has been configured.been configured.

•• Be aware of the issues that Be aware of the issues that come with mixing DHCP come with mixing DHCP and fixed addressingand fixed addressing

•• Ignore the above, and you Ignore the above, and you can expect a return trip to can expect a return trip to site.site.

Page 28: Network Troubleshooting Network Troubleshooting

Common Communication Common Communication ProblemsProblems

Transmitting polls, but get Transmitting polls, but get no response (Timeouts)no response (Timeouts)Received Data is rejectedReceived Data is rejectedCommunication stopsCommunication stopsCommunication exists with errors.Communication exists with errors.

Page 29: Network Troubleshooting Network Troubleshooting

Checking communications Checking communications quality using Ruinet (RUI):quality using Ruinet (RUI):1.1. Check Connection Overview for Check Connection Overview for

communication errorscommunication errors2.2. Check System Error screen for Check System Error screen for

System/Config errors (Messages are OK)System/Config errors (Messages are OK)3.3. Check Node & Map Descriptor overviews Check Node & Map Descriptor overviews

for missing Nodes/Map descriptorsfor missing Nodes/Map descriptors4.4. Check Data Array overview for data Check Data Array overview for data

update update

Page 30: Network Troubleshooting Network Troubleshooting

Common Communication Common Communication ProblemsProblemsTransmitting polls, but get no response Transmitting polls, but get no response (Timeouts)(Timeouts)•• This is the most common communication level This is the most common communication level

symptom.symptom.•• Cause is usually related to Installation or Network Cause is usually related to Installation or Network

setup errors, so review the previous slides.setup errors, so review the previous slides.•• Cause can manifest itself at any level Cause can manifest itself at any level

though, so finding the cause can though, so finding the cause can take time. Make use of all visual take time. Make use of all visual symptoms (TX/Rx LEDsymptoms (TX/Rx LED’’s, wiring, etc) s, wiring, etc) to reduce the range of possible to reduce the range of possible causes.causes.

Page 31: Network Troubleshooting Network Troubleshooting

Common Communication Common Communication ProblemsProblemsReceived Data is rejectedReceived Data is rejected•• The symptoms for this range from The symptoms for this range from

no response from the remote no response from the remote device, to a defined negative device, to a defined negative response.response.

•• There are several reasons why a poll is There are several reasons why a poll is rejected, based upon either a corrupted rejected, based upon either a corrupted message to incorrect parameters in a poll.message to incorrect parameters in a poll.

•• Corruption is caused by timing issues or poor Corruption is caused by timing issues or poor installation.installation.

•• Timing corrupts the messages when they Timing corrupts the messages when they are not delivered within the correct are not delivered within the correct timing parameters.timing parameters.

Page 32: Network Troubleshooting Network Troubleshooting

Common Communication Common Communication ProblemsProblemsCommunication stopsCommunication stops•• This is a very unusual This is a very unusual

symptom, but hard to nail symptom, but hard to nail down when it occurs down when it occurs (Mainly due to the fact that (Mainly due to the fact that the behavior is erratic)the behavior is erratic)

•• Stopped communication is Stopped communication is usually caused by usually caused by something event driven. something event driven. Work towards identifying Work towards identifying the event in order to the event in order to expedite finding the cause.expedite finding the cause.

Page 33: Network Troubleshooting Network Troubleshooting

Common Communication Common Communication ProblemsProblems

Communication exists with Communication exists with errors.errors.•• Partial communications could be Partial communications could be

related to many devices on the related to many devices on the network, and only some not network, and only some not communicating, or maybe even communicating, or maybe even some addresses on a device that some addresses on a device that are bad. Use the Hierarchical tiers are bad. Use the Hierarchical tiers in Ruinet to resolve this.in Ruinet to resolve this.

•• Another cause for partial Another cause for partial communications is poor quality communications is poor quality installation. If the same address installation. If the same address poll succeeds only some of the poll succeeds only some of the time, this is most likely related to time, this is most likely related to installation or timing.installation or timing.

Page 34: Network Troubleshooting Network Troubleshooting

Common Configuration Common Configuration ProblemsProblems

Client vs. Server mapping (wrong Client vs. Server mapping (wrong function)function)Responsible Map Descriptor Responsible Map Descriptor managementmanagementMissing titlesMissing titlesClient/Server node matchingClient/Server node matchingDuplicate names and/or addressesDuplicate names and/or addressesAddress range gapsAddress range gaps

Page 35: Network Troubleshooting Network Troubleshooting

Common Configuration Common Configuration ProblemsProblems

Client vs. Server mapping (wrong Client vs. Server mapping (wrong function)function)•• Restated, this problem occurs most Restated, this problem occurs most

commonly when no active commonly when no active communication devices are configured, communication devices are configured, or two active communication devices are or two active communication devices are configured when only one is allowed.configured when only one is allowed.

Responsible Map Descriptor Responsible Map Descriptor managementmanagement•• Active FieldServer mappings monitor the Active FieldServer mappings monitor the

status of communication to determine status of communication to determine the health of the corresponding data the health of the corresponding data array value/sarray value/s

•• Consequently it is not possible to have 2 Consequently it is not possible to have 2 active mappings pointing to the same active mappings pointing to the same data array offset/s.data array offset/s.

Page 36: Network Troubleshooting Network Troubleshooting

Common Configuration Common Configuration ProblemsProblems

Missing titlesMissing titles•• Configuration layout can be quite flexible, but one must Configuration layout can be quite flexible, but one must

take care with the titles (Title, Nodes, Connections, take care with the titles (Title, Nodes, Connections, Moves, Data Arrays, etc)Moves, Data Arrays, etc)

•• The FieldServer searches for the titles to know where to The FieldServer searches for the titles to know where to find the corresponding keywords and parameters, so the find the corresponding keywords and parameters, so the titles must be there.titles must be there.

Client/Server node matchingClient/Server node matching•• Node ID specified in the Node_ID field is almost always Node ID specified in the Node_ID field is almost always

the device address of the server or the passive the device address of the server or the passive communications device. This MUST be right for communications device. This MUST be right for communications to occur.communications to occur.

•• ““NodelessNodeless”” protocols do exist. By nature, these are point protocols do exist. By nature, these are point to point protocols where only one device is allowed to be to point protocols where only one device is allowed to be connected to any port.connected to any port.

Page 37: Network Troubleshooting Network Troubleshooting

Common Configuration Common Configuration ProblemsProblems

Duplicate names and/or addressesDuplicate names and/or addresses•• Duplicates can be hard to find and are sure to Duplicates can be hard to find and are sure to

cause problems. cause problems. •• One symptom to look for is individual One symptom to look for is individual

addresses not working when everything else is addresses not working when everything else is working.working.

Page 38: Network Troubleshooting Network Troubleshooting

Common Configuration ProblemsCommon Configuration ProblemsAddress range gapsAddress range gaps•• Be careful polling a device that Be careful polling a device that

documents gaps in the addressing documents gaps in the addressing system. Donsystem. Don’’t assume the addresses t assume the addresses are still there.are still there.

•• Polling a range of addresses containing a Polling a range of addresses containing a gap within the range will likely result in gap within the range will likely result in nothing being returned.nothing being returned.

•• Make a habit of providing Make a habit of providing ““zero datazero data”” for for unused addresses so when polled by a unused addresses so when polled by a block that includes unused addresses, block that includes unused addresses, FieldServer still responds.FieldServer still responds.

•• When serving data on FieldServer, it will When serving data on FieldServer, it will not combine two map descriptors to not combine two map descriptors to satisfy an incoming poll for data, so one satisfy an incoming poll for data, so one map descriptor must exist that covers the map descriptor must exist that covers the full range of the polled data for the full range of the polled data for the FieldServer to successfully respond.FieldServer to successfully respond.

Page 39: Network Troubleshooting Network Troubleshooting

Common Data Transfer Common Data Transfer ProblemsProblemsData Types (Typecasting)Data Types (Typecasting)Complex vs. Simple Data Complex vs. Simple Data StructuresStructuresBit PackingBit PackingSupported functionality Supported functionality in protocolsin protocolsImperial vs. MetricImperial vs. Metric

Page 40: Network Troubleshooting Network Troubleshooting

Common Data Transfer ProblemsCommon Data Transfer ProblemsData Types (Typecasting)Data Types (Typecasting)•• The FieldServer automatically typecasts data The FieldServer automatically typecasts data

unless special functions (like Packed Bit and unless special functions (like Packed Bit and special moves) are used.special moves) are used.

•• Be careful therefore, not to put float values in an Be careful therefore, not to put float values in an integer data arrays for example, unless of course integer data arrays for example, unless of course you want to truncate at the decimal point.you want to truncate at the decimal point.

Complex vs. Simple Data StructuresComplex vs. Simple Data Structures•• Protocols like LonWorks use complex data Protocols like LonWorks use complex data

structures to transfer multiple values in one data structures to transfer multiple values in one data address. address.

•• Plan carefully when mapping complex data Plan carefully when mapping complex data structures to simple data structures. You will structures to simple data structures. You will need to make sure complex types are kept need to make sure complex types are kept together in the right arrays, and that the correct together in the right arrays, and that the correct number of data array number of data array positions are allowed for, etc.positions are allowed for, etc.

Page 41: Network Troubleshooting Network Troubleshooting

Common Data Transfer ProblemsCommon Data Transfer ProblemsBit PackingBit Packing•• Be aware that some devices send 16 status bits in an Be aware that some devices send 16 status bits in an

integer to save address space and promote efficiency.integer to save address space and promote efficiency.•• Use Packed_Bit Data Arrays to provide binary status out Use Packed_Bit Data Arrays to provide binary status out

of a Packed_Bit integer.of a Packed_Bit integer.Supported functionality in protocolsSupported functionality in protocols•• Expect Expect ““present valuepresent value”” data to be transferred between data to be transferred between

different protocols at all times. However, auxiliary different protocols at all times. However, auxiliary properties (Like units, data quality, etc) is not always properties (Like units, data quality, etc) is not always supported by the supported by the ““otherother”” protocol.protocol.

•• E.g.: Transferring BACnet data to Modbus will get you E.g.: Transferring BACnet data to Modbus will get you the values you need, but the Units property will be lost the values you need, but the Units property will be lost since Modbus does not support this.since Modbus does not support this.

Imperial vs. MetricImperial vs. Metric•• Foreign made devices often provide Metric values. Foreign made devices often provide Metric values. •• Use Scaling in the FieldServer to do MetricUse Scaling in the FieldServer to do Metric-->Imperial >Imperial

conversionsconversions

Page 42: Network Troubleshooting Network Troubleshooting

ResourcesResourcesFieldServer Website FieldServer Website ((www.FieldServer.comwww.FieldServer.com))•• FieldServer Configuration ManualFieldServer Configuration Manual•• FieldServer Troubleshooting ManualFieldServer Troubleshooting Manual•• Troubleshooting Application notes (ENotes)Troubleshooting Application notes (ENotes)

Page 43: Network Troubleshooting Network Troubleshooting

Questions?Questions?

Email Mac at:Email Mac at:

[email protected]@comcast.net

Page 44: Network Troubleshooting Network Troubleshooting

THANK YOU!THANK YOU!

……..for taking the time to attend ..for taking the time to attend this presentation.this presentation.