FieldServer Driver – FieldBus
The LonWorks driver allows the FieldServer to transfer data to and from devices using LonWorks protocol. The FS-B30 Series and FS-B4011 can handle up to 4096 Network Variables and the FS-B2011 up to 1000 which can be of the Standard Network Variable Types (SNVT) and/or User-defined Network Variable Types (UNVT). The FieldServer LonWorks device can be used with explicit and/or implicit addressing and can be bound to a maximum of 15 other LonWorks nodes. The FS-B30 Series and FS-B4011 can handle a maximum of 4096 explicitly addressed nodes and the FS-B2011 up to 1000. The FieldServer currently supports a default of 63 network variable aliases to avoid network variable connection constraints.
The FieldServer can transfer data (Network Variables) in two ways.
- It can poll (request data from) other devices at a regular interval.
- It can send Network Variable Updates
- At a regular interval
- When the data has changed
- In throttled mode using minimum and maximum send time and change on delta parameters.
The FieldServer is capable of being configured by Network Management Tools such as LonMaker. For binding (implicit mode), a Network Management Tool is necessary to create the bindings. It is possible to place a FieldServer into a Network for explicit communications without using a Network Management Tool, but this requires intimate knowledge of the network in question.
The external interface file (.XIF) for the FieldServer can be uploaded from the FieldServer for the particular application. The FieldServer differs from most other LonWorks devices in that its XIF file is not fixed due to varying applications. The list of points available to the network will vary depending on the other networks connected to the FieldServer, and the requirements of the particular application. The recommended procedure for obtaining the XIF file for the FieldServer is to upload it.
The FieldServer provides the capability of defining multiple functional blocks, but only a single LonMark object. The user can create multiple functional blocks or a LonMark object by filling out the Node Self-Documentation String and the respective Network Variable Self-documentation String fields in the FieldServer configuration file.
The following table summarizes the FieldServer LonWorks driver’s capabilities:
|Number of NetworkVariables ||1000||4096||4096|
|Address Table Entries||15||15||15|
|Network Variable Aliases||63||63||63|
|Number of Domain Tables ||2||2||2|
|Support for SNVTs ||Yes||Yes||Yes|
|Support for UNVTs||Yes||Yes||Yes|
|Supports Polled NetworkVariables||Yes||Yes||Yes|
|Supports Network VariableUpdates||Yes||Yes||Yes|
|Supports ConfigurationProperties ||Yes||Yes||Yes|
|Supports Node and NetworkVariable Self-documentation Strings||Yes||Yes||Yes|
|Support for SCPTs ||Yes||Yes||Yes|
|Network Management Toolssuch as LonMaker Supported||Yes||Yes||Yes|
|Commissioning withoutNetwork Management Tool Supported ||Yes||Yes||Yes|
|Service Pin Supported||Yes||Yes||Yes|
|LonMark Object andFunctional Profiles definition ||Yes||Yes||Yes|
- The length of Network Variable names and complexity of the configuration may limit the actual number of usable Network Variables
- One of the two domains is the zero domain used by Network Management Tools
- SNVT Master List Version 11 is supported
- Implemented with Configuration Network Variables
- Only selected SCPTs are supported, extra SCPTs can be added on a per configuration basis
- Explicit Addressing Only
- Only approved LonMark objects are supported, see www.lonmark.org
|Clientor Server||1||TheFieldServer can only represent one LonWorks device on the LonWorks Network.
ALonWorks device is unique in terms of its Neuron Chip Identification Number.
Formal Driver Type
Client or Server
|FieldServer Model||Compatible with thisdriver|
|Connection type:||FTT-10 Free Topology Network Transceiver|
|Baud Rates:||78125 bps (bits per second)|
|Hardware interface:||PCC10 LonWorks adapter ISA card ( FS-X40 )
Built in LonWorks FTT-10 interface ( FS-X2011 )
|Device||Tested (FACTORY, SITE)|
|LonMaker for Windows V3.1||Factory/Site|
|Electronic Systems USA||Factory|
|Echelon ILon 100||Site|
|Invensys I/A Series||Factory|
|Circon UHC 300 (and others)||Factory|
|…and many others|
The connection diagram below shows how the FieldServer FS-X20, FS-X30 and FS-X40 are connected to a LonWorks network:
The 2-wire twisted-pair connection to the network is polarity insensitive. The FTT-10 network is a free topology network which supports star, loop and / or bus wiring connections. Please refer to the FTT-10A Free Topology Transceiver User’s Guide from Echelon Corporation for recommended wiring practices if necessary.
Communications functions – Supported functions at a glance:
Data Types Supported
|FieldServer Data Type||Description (or Device Data Type)|
|Integers ( Long, short, signed, unsigned )||SNVTs and UNVTs can be presented, stored and moved intoany FieldServer data type|
Read Operations supported
|FieldServer as a Client||FieldServer as a Server|
|Polled Network Variables:||Polled NetworkVariables:|
|-Send Network VariableFetch||-Respond to NetworkVariable Fetch|
|-Send Network Variable Poll||-Respond to NetworkVariable Poll|
Write (Control) Operations supported
|FieldServer as a Client||FieldServer as a Server|
|Network VariablesUpdates:||Network VariablesUpdates:|
|-Send Network VariableUpdates||-Accept Network VariableUpdates|
Unsupported Functions and Data Types
|Programming messages||FieldServer is a data transfer device, and as such,programming messages are not required|
|Direct Memory Read / Writes under user control||The driver uses the Echelon MIP which handles directmemory read and writes|