Schneider Electric INTERBUS Basic Network Interface Module Internal, Process Image, Word, Rules

Page 39

 

Fieldbus Communications Support

 

 

The Internal

The STB NIB 1010’s process image contains memory areas (buffers) for the

Process Image

temporary storage of input and output data. The internal process image is part of the

 

NIM’s island bus scanner area.

 

The island bus manages data exchange in both directions:

 

input data from the island bus—The island bus scanner operates continuously,

 

gathering data as well as status and confirmation bits and putting them into the

 

￿process image’s input buffer.

 

output data to the island bus—The island bus scanner handles output data and

 

places it in the process image’s output buffer.

 

Input data and output data are assembled in the order of the island bus I/O modules

 

(from left to right).

Word

 

Every entry in the process image is in a multiple-word format. If modules on the

Boundaries and

island bus have input or output data entries that are not multiple words, the

Bit Packing

corresponding word in the process image is moved to the next word boundary.

 

For example, a module with one bit of output data starts on a word boundary in the

 

process image’s output data buffer. The next process image entry starts on the next

 

word boundary, thereby transmitting 15 unused bits of the module’s first word,

 

resulting in latency during data transmission on the fieldbus.

 

Bit packing allows bits of data on the fieldbus from different digital I/O modules to be

 

put together in a single byte, resulting in optimized bandwidth.

Bit Packing

 

The STB NIB 1010 NIM observes the following rules for the bit packing of the

Rules

external process image:

 

The input and output process image sizes are limited to 16 words each.

 

The first word of the input process image contains NIM status information. The

 

first word of the output process image contains the NIM control word.

 

Bit packing follows the addressing order of the island bus I/O modules, from left

 

to right in the basic segment.

 

When the data object (or echo output data object) for a specific module is

 

available, it precedes the status object for that module.

 

Status objects and data objects for the same or different I/O module may be

 

packed in the same word if the size of the combined objects is 16 bits or less.

 

If the combination of objects requires more than 16 bits, the objects will be placed

 

in separate contiguous bytes. A single object cannot be split over two

 

￿word boundaries.

 

For standard analog input modules, channel 1 data is followed immediately by

 

channel 1 status, then channel 2 data and channel 2 status.

 

 

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Contents 890USE19600 Version Advantys STBPage Table of Contents Application Example Safety Information ProcedureImportant Information Safety Information Construed as a commitment by Schneider Electric About the BookAt a Glance Validity NoteAbout the Book Introduction Summary What’s in this Chapter?Topic Basic What Is Advantys STB?Introduction Island Bus I/OWhat Is a Network Interface Module? Structural About Interbus Outputs in 4 msComponents of a simplified Interbus network are shown below Topology Physical LayerOn the shift register ring on which data is circulated NodeAddressing Input and output data in the masters bufferIntroduction Chapter? Product specifications of the basic Interbus NIMSTB NIB Basic NIM Module What’s in thisHardware External Features of the STB NIB 1010 NIMFeatures Called out in the illustration below Feature FunctionSpace reserved for the network connectors NIM housing Connections STB NIB 1010 Fieldbus InterfaceSummary Fieldbus PortCable ConnectorsInterbus NetworkingIndications LED Physical DescriptionOverview GeneralLEDs NIM ActivityDescription Power Supply InterfaceIsland is the two-receptacle connector illustrated below PhysicalRight Use eitherImproper Galvanic Isolation Logic PowerExternal CharacteristicsPower Supply RequirementsTechnical Specifications STB NIB 1010 Module SpecificationsConfiguring the Island Bus Bus Address Basic island configurationAuto-Addressing About the IslandModule Physical Location Island Bus Address An ExampleAuto-Configuration ConfigurationAbout Auto Stage Been successfully configured at least onceRST Button Hinged coverHeartbeat Island Fallback ScenariosFallback ScenariosIntroduction What’s in this Chapter? Fieldbus Communications SupportData Type Interbus ID CodeLow High BytesData Length Objects Data ExchangeData and Status ObjectsBoundaries InternalProcess Image WordContains the NIM status Output DataInput Data ExchangeWith an Advantys STB NIB 1010 basic NIM Application ExampleSample Island Sample Island AssemblyAssembly Fieldbus networkModel Module Type Island Bus Address I/O modules have the following island bus addressesDevices on an Interbus network Network Configuration ConsiderationsFor use with an Advantys STB island ConnectionConsiderations Before YouBegin SyConStep Action Comment Using SyCon to Configure an STB Island on InterbusWith SyCon Stage DescriptionWorkspace To add the NIM to the network configurationConfiguring Add the NIMInstructions Create an EDSSaving Using CMD to Configure an STB Island on Interbus Island slave to your configuration using CMDCMD Downloading AddAdding Island SlaveApplication Example Glossary BOS ARPCRC CanCOB ComsEIA DhcpDIN EDSFedp EMCEMI EOSGSD FsdpIEC type 1 input BaseScanning IECInput response Industrial I/OInput filtering Input polarityNema Energized and open when the coil is energizedEnergized and closed when the coil is energized ContactNMT NIMPDM PDOPLC Profibus DP Process I/OProducer Consumer modelSDO RTDSAP ScadaSnmp SmmpsStdp TCPTFE Voltage group UDPVaristor Suppress transient voltage surgesIndex Interbus Heartbeat message, 34 housing ID codeIndex
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