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

Network Network Troubleshooting Troubleshooting

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Page 1: Network Network Troubleshooting Troubleshooting

Network Network TroubleshootingTroubleshooting

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

Page 2: Network Network Troubleshooting 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 Network Troubleshooting Troubleshooting

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

between equipmentbetween equipment5.5. Check communication qualityCheck communication quality6.6. Check data transferCheck data transfer

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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).

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Common Wiring ProblemsCommon Wiring ProblemsRSRS--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 Network Troubleshooting Troubleshooting

Common Wiring ProblemsCommon Wiring ProblemsRSRS--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 theIf the same light is on solid (RD or TD) when either side of the test test box is connected on its own, then the polarity is wrong.box is connected on its own, then the polarity is 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 disconnected. Receive will have a zero voltage, Transmit will have a negative voltage of will 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 Network Troubleshooting Troubleshooting

Common Wiring ProblemsCommon Wiring ProblemsRSRS--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 with communications problems or even interfere with the operation of the device.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 the problem, use an optical isolator to separate the wiring. Optical Isolators wiring. Optical Isolators are offare off--thethe--shelf items shelf items that can be purchased that can be purchased online.online.

Page 8: Network Network Troubleshooting Troubleshooting

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

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

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Common Wiring ProblemsCommon Wiring ProblemsRSRS--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.

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Common Wiring ProblemsCommon Wiring ProblemsRSRS--485485::

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

Page 11: Network Network Troubleshooting Troubleshooting

Common Wiring ProblemsCommon Wiring ProblemsRSRS--485 Polarity:485 Polarity:

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

Page 12: Network Network Troubleshooting Troubleshooting

Common Wiring ProblemsCommon Wiring ProblemsRSRS--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 the resistors plus 10kOhm resistors between the signal and ground/5V.signal and ground/5V.

Page 13: Network Network Troubleshooting Troubleshooting

Common Wiring ProblemsCommon Wiring ProblemsRSRS--485 4485 4--wire vs. 2wire vs. 2--wire:wire:

FieldServer supports 2FieldServer supports 2--wire RSwire RS--485 communications, which is 485 communications, which is half duplex RShalf duplex RS--485 and is the more common format found in 485 and is the more common format found in industry.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 wire RSRS--485 will allow you to connect to a 2485 will allow you to connect to a 2--wire RSwire RS--485 setup by 485 setup by bridging the Rx and Tx lines to make 2 wires out of 4. These bridging the Rx and Tx lines to make 2 wires out of 4. These devices tolerate the visibility of Tx signals on their Rx lines.devices tolerate the visibility of Tx signals on their Rx lines.However, other 4However, 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 Network Troubleshooting Troubleshooting

Common Wiring ProblemsCommon Wiring ProblemsRSRS--485 Cable Length:485 Cable Length:

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

Page 15: Network Network Troubleshooting Troubleshooting

Common Wiring ProblemsCommon Wiring ProblemsEthernetEthernet::

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

Page 16: Network Network Troubleshooting Troubleshooting

Common Wiring ProblemsCommon Wiring ProblemsEthernet 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 made experienced is assembly quality. Factory made cables are usually precables are usually pre--tested and tend to work, tested and tend to work, but cable crimped on site often leads to but cable crimped on site often leads to problems that are not immediately obvious. problems that are not immediately obvious.

Page 17: Network Network Troubleshooting Troubleshooting

Common Wiring ProblemsCommon Wiring ProblemsEthernet 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 same them together, facing the same way (e.g.: both clips facing way (e.g.: both clips facing away from you). If the wire away from you). If the wire colors follow the same pattern colors follow the same pattern on both connectors, then it is a on both connectors, then it is a direct cable.direct cable.

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Common Networking ProblemsCommon Networking ProblemsRSRS--232 & RS232 & RS--485:485:

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

Page 19: Network Network Troubleshooting Troubleshooting

Common Networking ProblemsCommon Networking ProblemsRSRS--232 & RS232 & RS--485:485:

Baud RateBaud RateDonDon’’t just check Baud Rate. Check Parity, Data Bits and Stop t just check Baud Rate. Check Parity, Data Bits and Stop bits too.bits too.All devices on the same RSAll devices on the same RS--485 network need to communicate 485 network need to communicate at the same baud rate. Make sure this is possible.at the same baud rate. Make sure this is possible.

Master vs. Slave.Master vs. Slave.For Master/Slave networks (e.g.: Modbus, Metasys), one Master For Master/Slave networks (e.g.: Modbus, Metasys), one Master usually controls all communicationsusually controls all communicationsMake 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 Network Troubleshooting Troubleshooting

Common Networking ProblemsCommon Networking ProblemsRSRS--232 & RS232 & RS--485:485:

HandshakingHandshakingSome devices/protocols Some devices/protocols demand startup demand startup handshaking like the handshaking like the passing of passwords passing of passwords and device information. and device information. Check literature for Check literature for requirements and requirements and default passwords.default passwords.

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Common Networking ProblemsCommon Networking ProblemsRSRS--232 & RS232 & RS--485:485:

AddressingAddressingMake sure the correct device address is Make sure the correct device address is being used. This is not always obvious being used. This is not always obvious (e.g.: BACnet MSTP)(e.g.: BACnet MSTP)Server devices almost always need Server devices almost always need addresses, but sometimes you need to addresses, but sometimes you need to configure client addresses too (e.g.: configure client addresses too (e.g.: DNP 3.0)DNP 3.0)Some protocols may demand address Some protocols may demand address paths or addresses at multiple levels paths or addresses at multiple levels (e.g.: Modbus +, McQuay)(e.g.: Modbus +, McQuay)

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Common Networking ProblemsCommon Networking ProblemsRSRS--232 & RS232 & RS--485:485:

Poll timingPoll timingTiming can be a very complicated issue and is not Timing can be a very complicated issue and is not uncommon as a cause for poor communicationsuncommon as a cause for poor communicationsThere are many timing factors to be aware of in a There are many timing factors to be aware of in a communications session (e.g.: Timeouts, poll delay, communications session (e.g.: Timeouts, poll delay, retry intervals, scan intervals, probation delays, Inter retry intervals, scan intervals, probation delays, Inter character timing, etc)character timing, etc)Enote067 is very helpful in Enote067 is very helpful in helping understand how helping understand how these parameters interactthese parameters interactSymptoms of a timing problem Symptoms of a timing problem are usually related to the are usually related to the presence of partial presence of partial communicationscommunications

Page 23: Network Network Troubleshooting Troubleshooting

Common Networking ProblemsCommon Networking ProblemsEthernetEthernet::

Subnets and gatewaysSubnets and gatewaysFirewalls.Firewalls.PortsPortsAddressingAddressing

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Common Networking ProblemsCommon Networking ProblemsEthernet:Ethernet:

Subnets and gatewaysSubnets and gatewaysA common problem in Ethernet is that IP A common problem in Ethernet is that IP addresses get set up correctly without the addresses get set up correctly without the subnets and/or gateway addresses being set subnets and/or gateway addresses being set up correctlyup correctlyProtocols differ in their Protocols differ in their IP/Subnet/gateway IP/Subnet/gateway requirements, so be requirements, so be aware of the requirements aware of the requirements for the separate protocols.for the separate protocols.

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Common Networking ProblemsCommon Networking ProblemsEthernet:Ethernet:

Firewalls.Firewalls.The thing about firewalls are The thing about firewalls are that they are invisible to the that they are invisible to the installer, but can stop installer, but can stop communications in a heartbeatcommunications in a heartbeatWork with the Systems Work with the Systems Administrator to ensure that all Administrator to ensure that all necessary holes are made in necessary holes are made in the firewalls for the application, the firewalls for the application, and that the network design is and that the network design is compatible with the companycompatible with the company’’s s security policies.security policies.

Page 26: Network Network Troubleshooting Troubleshooting

Common Networking ProblemsCommon Networking ProblemsEthernet:Ethernet:

PortsPortsBe aware that Ethernet protocols have ports too. However, they Be aware that Ethernet protocols have ports too. However, they are logical, not physical. Be aware of the port required for a are logical, not physical. Be aware of the port required for a given protocol, you may need to open a hole in a firewall for thgiven protocol, you may need to open a hole in a firewall for that at port.port.

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

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Common Networking ProblemsCommon Networking ProblemsEthernet:Ethernet:

System AdministrationSystem AdministrationWhen adding devices to an When adding devices to an existing network, be aware that existing network, be aware that this cannot be done without this cannot be done without knowledge of what exists on the knowledge of what exists on the network.network.When doing a new network, When doing a new network, leave a good document trail of leave a good document trail of how the network has been how the network has been configured.configured.Be aware of the issues that Be aware of the issues that come with mixing DHCP and come with mixing DHCP and fixed addressingfixed addressingIgnore the above, and you can Ignore the above, and you can expect a return trip to site.expect a return trip to site.

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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.

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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 System/Config Check System Error screen for System/Config

errors (Messages are OK)errors (Messages are OK)3.3. Check Node & Map Descriptor overviews for Check Node & Map Descriptor overviews for

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

Page 30: Network Network Troubleshooting Troubleshooting

Common Communication Common Communication ProblemsProblems

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

Page 31: Network Network Troubleshooting Troubleshooting

Common Communication Common Communication ProblemsProblems

Received Data is rejectedReceived Data is rejectedThe 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 rejected, There are several reasons why a poll is rejected, based upon either a corrupted message to incorrect based upon either a corrupted message to incorrect parameters in a poll.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 timing are not delivered within the correct timing parameters.parameters.

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Common Communication Common Communication ProblemsProblems

Communication stopsCommunication stopsThis 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.

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Common Communication Common Communication ProblemsProblems

Communication exists with errors.Communication exists with errors.Partial communications could be Partial communications could be related to many devices on the network, related to many devices on the network, and only some not communicating, or and only some not communicating, or maybe even some addresses on a maybe even some addresses on a device that are bad. Use the device that are bad. Use the Hierarchical tiers in Ruinet to resolve Hierarchical tiers in Ruinet to resolve this.this.Another cause for partial Another cause for partial communications is poor quality communications is poor quality installation. If the same address poll installation. If the same address poll succeeds only some of the time, this is succeeds only some of the time, this is most likely related to installation or most likely related to installation or timing.timing.

Page 34: Network Network Troubleshooting Troubleshooting

Common Configuration Common Configuration ProblemsProblems

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

Page 35: Network Network Troubleshooting Troubleshooting

Common Configuration Common Configuration ProblemsProblems

Client vs. Server mapping (wrong Client vs. Server mapping (wrong function)function)

Restated, this problem occurs most commonly Restated, this problem occurs most commonly when no active communication devices are when no active communication devices are configured, or two active communication configured, or two active communication devices are configured when only one is devices are configured when only one is allowed.allowed.

Responsible Map Descriptor Responsible Map Descriptor managementmanagement

Active FieldServer mappings monitor the Active FieldServer mappings monitor the status of communication to determine the status of communication to determine the health of the corresponding data array value/shealth of the corresponding data array value/sConsequently it is not possible to have 2 Consequently it is not possible to have 2 active mappings pointing to the same data active mappings pointing to the same data array offset/s.array offset/s.

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Common Configuration Common Configuration ProblemsProblems

Missing titlesMissing titlesConfiguration layout can be quite flexible, but one must take caConfiguration layout can be quite flexible, but one must take care re with the titles (Title, Nodes, Connections, Moves, Data Arrays, with the titles (Title, Nodes, Connections, Moves, Data Arrays, etc)etc)The FieldServer searches for the titles to know where to find thThe FieldServer searches for the titles to know where to find the e corresponding keywords and parameters, so the titles must be corresponding keywords and parameters, so the titles must be there.there.

Client/Server node matchingClient/Server node matchingNode ID specified in the Node_ID field is almost always the Node ID specified in the Node_ID field is almost always the device address of the server or the passive communications device address of the server or the passive communications device. This MUST be right for communications to occur.device. This MUST be right for communications to occur.““NodelessNodeless”” protocols do exist. By nature, these are point to point protocols do exist. By nature, these are point to point protocols where only one device is allowed to be connected to protocols where only one device is allowed to be connected to any port.any port.

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Common Configuration Common Configuration ProblemsProblems

Duplicate names and/or addressesDuplicate names and/or addressesDuplicates can be hard to find and are sure to cause Duplicates can be hard to find and are sure to cause problems. problems. One symptom to look for is individual addresses not One symptom to look for is individual addresses not working when everything else is working.working when everything else is working.

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Common Configuration Common Configuration ProblemsProblems

Address range gapsAddress range gapsBe careful polling a device that documents gaps in Be careful polling a device that documents gaps in the addressing system. Donthe addressing system. Don’’t assume the addresses t assume the addresses are still there.are still there.Polling a range of addresses containing a gap within Polling a range of addresses containing a gap within the range will likely result in nothing being returned.the range will likely result in nothing being returned.Make a habit of providing Make a habit of providing ““zero datazero data”” for unused for unused addresses so when polled by a block that includes addresses so when polled by a block that includes unused addresses, FieldServer still responds.unused addresses, FieldServer still responds.When serving data on FieldServer, it will not combine When serving data on FieldServer, it will not combine two map descriptors to satisfy an incoming poll for two map descriptors to satisfy an incoming poll for data, so one map descriptor must exist that covers data, so one map descriptor must exist that covers the full range of the polled data for the FieldServer to the full range of the polled data for the FieldServer to successfully respond.successfully respond.

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Common Data Transfer Common Data Transfer ProblemsProblems

Data 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

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Common Data Transfer Common Data Transfer ProblemsProblems

Data Types (Typecasting)Data Types (Typecasting)The FieldServer automatically typecasts data unless The FieldServer automatically typecasts data unless special functions (like Packed Bit and special moves) special functions (like Packed Bit and special moves) are used.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 you integer data arrays for example, unless of course you want to truncate at the decimal point.want to truncate at the decimal point.

Complex vs. Simple Data StructuresComplex vs. Simple Data StructuresProtocols like LonWorks use complex data structures Protocols like LonWorks use complex data structures to transfer multiple values in one data address. to transfer multiple values in one data address. Plan carefully when mapping complex data structures Plan carefully when mapping complex data structures to simple data structures. You will need to make sure to simple data structures. You will need to make sure complex types are kept together in the right arrays, complex types are kept together in the right arrays, and that the correct number of data array and that the correct number of data array positions are allowed for, etc.positions are allowed for, etc.

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Common Data Transfer Common Data Transfer ProblemsProblems

Bit PackingBit PackingBe aware that some devices send 16 status bits in an integer to Be aware that some devices send 16 status bits in an integer to save address space and promote efficiency.save address space and promote efficiency.Use Packed_Bit Data Arrays to provide binary status out of a Use Packed_Bit Data Arrays to provide binary status out of a Packed_Bit integer.Packed_Bit integer.

Supported functionality in protocolsSupported functionality in protocolsExpect Expect ““present valuepresent value”” data to be transferred between different data to be transferred between different protocols at all times. However, auxiliary properties (Like unitprotocols at all times. However, auxiliary properties (Like units, s, data quality, etc) is not always supported by the data quality, etc) is not always supported by the ““otherother”” protocol.protocol.E.g.: Transferring BACnet data to Modbus will get you the valuesE.g.: Transferring BACnet data to Modbus will get you the valuesyou need, but the Units property will be lost since Modbus does you need, but the Units property will be lost since Modbus does not support this.not support this.

Imperial vs. MetricImperial vs. MetricForeign 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

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ResourcesResources

FieldServer Website (FieldServer Website (www.FieldServer.comwww.FieldServer.com))FieldServer Configuration ManualFieldServer Configuration ManualFieldServer Troubleshooting ManualFieldServer Troubleshooting ManualTroubleshooting Application notes (ENotes)Troubleshooting Application notes (ENotes)

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Questions?Questions?

Email Mac at:Email Mac at:

[email protected]@comcast.net

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THANK YOU!THANK YOU!

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