BACnet通讯分析,bacnet报文分析

('BACnet通讯1、概述.系统实现基于BACnet/IP（又称B/IP）网络进行通讯。BACnet虚拟链路层（BVLL）提供了BACnet网络层和某指定的通讯子系统的接口，本文指定了BACnet虚拟链路控制（BVLC）要求支持的定向和广播信息。本实现关于BACnet协议定义主要可分为三层：B/IP网络虚拟层，BACnet网络层和BACnet应用层。B/IP提供了TCP/IP一样的通讯结构，采用UDP的通讯方式。本文接下来将对此三层结构进行详细的讲解。其文本协议的大致格式如下：BACnet/IPBACnet网络层BACnet应用层BVLCTypeBVLCFunctionLengthNPDUAPDUNPDU：BACnet网络层数据结构，下文进行详细的讲解APDU：BACnet应用层数据结构，下文进行详细的讲解2、BACnet/IP.BVLCType：0x81，代表BACnet/IP网络BVLCFunction：指定报文的类型，何种作用；本应用使用的报文类型分为两种：0A：点对点通讯0B：广播通信Length：指定报文的长度，包括BVLCType、BVLCFunction以及本身在内NPDU：根据不同情况，报文长短不同，见下文的解析。APDU：根据NPDU不同以及不同的请求，报文不同，见下文的解析。3、BACnetNPDU结构.版本信息1ByteVersion控制字1ByteControl目标网络号2BytesDNET目标网络长度1ByteDLEN目标地址可变长度DADR原网络号2BytesSNET原网络长度1ByteSLEN原地址可变SNET路由数目1ByteHopCount消息类型1ByteMessageType卖方ID2BytesVendorID应用层信息可变APDU版本信息：默认0x01控制字：BIT7：1表示MessageType存在，为0时MessageType不存在BIT6：保留，为0BIT5：1表示DNETDLENHopCount存在，当DLEN为0时表明广播网络DADR不存在；0表示DNETDLENDADRHopCount不存在BIT4：保留，为0BIT3：1表示SNETSLEN存在，当SLEN为0时表明无效SADR不存在；0表示SNETSLENSADRHopCount不存在BIT2：1表示为一个需确认的请求数据单元，一复杂ACK数据单元或一网络层信息非reply的；0表示除去上述情形的数据单元BIT1、0：网络优先级11=LifeSafetymessage10=CriticalEquipmentmessage01=Urgentmessage00=Normalmessage目标网络号：FFFF的时候表示广播目标长度：表示DADR的长度目标地址：目标网络MAC地址原网络号：同目标网络号原网络长度：表示SADR的长度原地址：原网络的MAC地址路由数目：数据需要经过的路由个数，当不存在DNET的时候，需设置为FF消息类型：X\'00\':Who-Is-Router-To-NetworkX\'01\':I-Am-Router-To-NetworkX\'02\':I-Could-Be-Router-To-NetworkX\'03\':Reject-Message-To-NetworkX\'04\':Router-Busy-To-NetworkX\'05\':Router-Available-To-NetworkX\'06\':Initialize-Routing-TableX\'07\':Initialize-Routing-Table-AckX\'08\':Establish-Connection-To-NetworkX\'09\':Disconnect-Connection-To-NetworkX\'0A\'toX\'7F\':ReservedforusebyASHRAEX\'80\'toX\'FF\':Availableforvendorproprietarymessages卖方ID：当控制字的BIT7为1并且消息类型为X\'80\'toX\'FF\':的时候，才会存在本次开发没有用到，不再解释本次应用中控制字只用到0x20和0x04两种，前者为广播查询设备，后者微点对对取设备数据或属性。4、BACnetAPDU结构：（应用层协议数据单元）BACnet网络层数据主要分为一下几种：BACnetPDU::=CHOICE{confirmed-request-PDU[0]BACnet-Confirmed-Request-PDU,unconfirmed-request-PDU[1]BACnet-Unconfirmed-Request-PDU,simpleACK-PDU[2]BACnet-SimpleACK-PDU,complexACK-PDU[3]BACnet-ComplexACK-PDU,segmentAck-PDU[4]BACnet-SegmentACK-PDU,error-PDU[5]BACnet-Error-PDU,reject-PDU[6]BACnet-Reject-PDU,abort-PDU[7]BACnet-Abort-PDU}对于本次应用，主要用到了BACnet-Confirmed-Request-PDU（需确认的请求协议数据单元）BACnet-Unconfirmed-Request-PDU（无需确认的请求协议数据单元）BACnet-ComplexACK-PDU（复杂的ACK命令）BACnet-Error-PDU（报错的协议数据单元）对于上述几种数据的分类主要根据pdutype（下文进行讲解）进行判定。4.1.BACnet-Confirmed-Request-PDU的结构：BACnet-Confirmed-Request-PDU::=SEQUENCE{pdu-type[0]Unsigned(0..15),--0forthisPDUtypesegmented-message[1]BOOLEAN,more-follows[2]BOOLEAN,segmented-response-accepted[3]BOOLEAN,reserved[4]Unsigned(0..3),--mustbesettozeromax-segments-accepted[5]Unsigned(0..7),--asper20.1.2.4max-APDU-length-accepted[6]Unsigned(0..15),--asper20.1.2.5invokeID[7]Unsigned(0..255),sequence-number[8]Unsigned(0..255)OPTIONAL,--onlyifsegmentedmsgproposed-window-size[9]Unsigned(1..127)OPTIONAL,--onlyifsegmentedmsgservice-choice[10]BACnetConfirmedServiceChoice,service-request[11]BACnet-Confirmed-Service-RequestOPTIONAL}BIT7BIT6BIT5BIT4BIT3BIT2BIT1BIT0PDUTYPESEGMORSA00MaxSegsMaxRespInvokeIDSequenceNumber(onlypresentbySEG==1)ProposedWindowSize(onlypresentbySEG==1)ServiceChioceServiceRequest……PDUType0(BACnet-Confirmed-Service-Request-PDU)SEG0(UnsegmentedRequest)1(SegmentedRequest)MOR0(NoMoreSegmentsFollow)1(MoreSegmentsFollow)SA0(SegmentedResponsenotaccepted)1(SegmentedResponseaccepted)MaxSegs(0..7)(Numberofresponsesegmentsacceptedper20.1.2.4)MaxResp(0..15)(SizeofMaximumAPDUacceptedper20.1.2.5)InvokeID(0..255)SequenceNumber(0..255)OnlypresentifSEG=1ProposedWindowSize(1..127)OnlypresentifSEG=1ServiceChoiceBACnetConfirmedServiceChoiceServiceRequestVariableEncodingSEG：指出当前的数据单元是否为完整的还是为一部分分段信息MOR：指出是否还有更多的分段信息SA：为1时指出将收到一个复杂的回应（complexack）MaxSegs：指出设备将要接收到多少分段信息B\'000\'Unspecifiednumberofsegmentsaccepted.B\'001\'2segmentsaccepted.B\'010\'4segmentsaccepted.B\'011\'8segmentsaccepted.B\'100\'16segmentsaccepted.B\'101\'32segmentsaccepted.B\'110\'64segmentsaccepted.B\'111\'Greaterthan64segmentsaccepted.MaxResp：指出将收到的（APDU）最大长度B\'0000\'UptoMinimumMessageSize(50octets)B\'0001\'Upto128octetsB\'0010\'Upto206octets(fitsinaLonTalkframe)B\'0011\'Upto480octets(fitsinanARCNETframe)B\'0100\'Upto1024octetsB\'0101\'Upto1476octets(fitsinanISO8802-3frame)InvokeID：调用者IDServiceChioce：此处表明次报文的作用，详见BACnetConfirmedServiceChoiceServiceRequest：根据BACnetConfirmedServiceChoice不同而结构不同，详见BACnet-Confirmed-Service-RequestBACnetConfirmedServiceChoice::=枚举类型{--AlarmandEventServicesacknowledgeAlarm(0),confirmedCOVNotification(1),confirmedEventNotification(2),getAlarmSummary(3),getEnrollmentSummary(4),getEventInformation(29),subscribeCOV(5),subscribeCOVProperty(28),lifeSafetyOperation(27),--FileAccessServicesatomicReadFile(6),atomicWriteFile(7),--ObjectAccessServicesaddListElement(8),removeListElement(9),createObject(10),deleteObject(11),readProperty(12),readPropertyConditional(13),readPropertyMultiple(14),readRange(26),writeProperty(15),writePropertyMultiple(16),。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。}上述标记为红色的表示本次应用中所用到的，所以只对这些进行讲解。可以根据BACnetConfirmedServiceChoice找到相对应的Request或者Ack的数据的结构BACnet-Confirmed-Service-Request::=CHOICE//对应上面的Choice{--AlarmandEventServicesacknowledgeAlarm[0]AcknowledgeAlarm-Request,confirmedCOVNotification[1]ConfirmedCOVNotification-Request,confirmedEventNotification[2]ConfirmedEventNotification-Request,--getAlarmSummaryconveysnoparametersgetEnrollmentSummary[4]GetEnrollmentSummary-Request,getEventInformation[29]GetEventInformation-Request,subscribeCOV[5]SubscribeCOV-Request,subscribeCOVProperty[28]SubscribeCOVProperty-Request,lifeSafetyOperation[27]LifeSafetyOperation-Request,--FileAccessServicesatomicReadFile[6]AtomicReadFile-Request,atomicWriteFile[7]AtomicWriteFile-Request,--ObjectAccessServicesaddListElement[8]AddListElement-Request,removeListElement[9]RemoveListElement-Request,createObject[10]CreateObject-Request,deleteObject[11]DeleteObject-Request,readProperty[12]ReadProperty-Request,readPropertyConditional[13]ReadPropertyConditional-Request,readPropertyMultiple[14]ReadPropertyMultiple-Request,readRange[26]ReadRange-Request,writeProperty[15]WriteProperty-Request,writePropertyMultiple[16]WritePropertyMultiple-Request,。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。}上述标记为红色的既是针对BACnetConfirmedServiceChoice所用到的数据结构。ReadProperty-Request::=SEQUENCE//读数据请求和读数据回答{objectIdentifier[0]BACnetObjectIdentifier,propertyIdentifier[1]BACnetPropertyIdentifier,propertyArrayIndex[2]UnsignedOPTIONAL--usedonlywitharraydatatype}ReadPropertyMultiple-Request::=SEQUENCE{listOfReadAccessSpecsSEQUENCEOFReadAccessSpecification}ReadAccessSpecification::=SEQUENCE{objectIdentifier[0]BACnetObjectIdentifier,listOfPropertyReferences[1]SEQUENCEOFBACnetPropertyReference}BACnetPropertyReference::=SEQUENCE{propertyIdentifier[0]BACnetPropertyIdentifier,propertyArrayIndex[1]UnsignedOPTIONAL--usedonlywitharraydatatype--ifomittedwithanarraytheentirearrayisreferenced}BACnetPropertyIdentifier::=ENUMERATED{accepted-modes(175),acked-transitions(0),ack-required(1),action(2),action-text(3),active-text(4),active-vt-sessions(5),active-cov-subscriptions(152),adjust-value(176),alarm-value(6),alarm-values(7),all(8),all-writes-successful(9),apdu-segment-timeout(10),apdu-timeout(11),application-software-version(12),firmware-revision(44),archive(13),attempted-samples(124),list-of-group-members(53),list-of-object-property-references(54),list-of-session-keys(55),local-date(56),local-time(57),location(58),maintenance-required(158),manipulated-variable-reference(60),manual-slave-address-binding(170),maximum-output(61),maximum-value(135),maximum-value-timestamp(149),max-apdu-length-accepted(62),max-info-frames(63),max-master(64),max-pres-value(65),max-segments-accepted(167),member-of(159),minimum-off-time(66),minimum-on-time(67),minimum-output(68),event-state(36),model-name(70),number-of-APDU-retries(73),object-identifier(75),object-list(76),object-name(77),object-property-reference(78),object-type(79),operation-expected(161),optional(80),out-of-service(81),output-units(82),--seeevent-parameters(83),polarity(84),prescale(185),present-value(85),priority(86),pulse-rate(186),priority-array(87),priority-for-writing(88),protocol-object-types-supported(96),protocol-revision(139),protocol-services-supported(97),protocol-version(98),reliability(103),relinquish-default(104),schedule-default(174),segmentation-supported(107),state-text(110),status-flags(111),stop-time(143),stop-when-full(144),system-status(112),tracking-value(164),units(117),variance-value(151),vendor-identifier(120),vendor-name(121),--seedatabase-revision(155),}上述标记为红色者既是本次应用所用到的属性对象BACnetObjectIdentifier的编码分为两个部分：ObjecttypeInstanceNumber占用了10Bits占用了22BitsObjectType的表格如下：BACnetObjectTypesSupported::=BITSTRING{--accumulator(23),analog-input(0),analog-output(1),analog-value(2),--averaging(18),binary-input(3),binary-output(4),binary-value(5),calendar(6),command(7),device(8),event-enrollment(9),file(10),group(11),loop(12),multi-state-input(13),multi-state-output(14),--multi-state-value(19),notification-class(15),program(16),}设备对象所具备的所有属性及其数据结构如下：DEVICE::=SEQUENCE{object-identifier[75]BACnetObjectIdentifier,object-name[77]CharacterString,object-type[79]BACnetObjectType,system-status[112]BACnetDeviceStatus,vendor-name[121]CharacterString,vendor-identifier[120]Unsigned16,model-name[70]CharacterString,firmware-revision[44]CharacterString,application-software-version[12]CharacterString,location[58]CharacterStringOPTIONAL,description[28]CharacterStringOPTIONAL,protocol-version[98]Unsigned,protocol-revision[139]Unsigned,protocol-services-supported[97]BACnetServicesSupported,protocol-object-types-supported[96]BACnetObjectTypesSupported,object-list[76]SEQUENCEOFBACnetObjectIdentifier,--accessedasaBACnetARRAYmax-APDU-length-supported[62]Unsigned,segmentation-supported[107]BACnetSegmentation,vt-classes-supported[122]SEQUENCEOFBACnetVTClassOPTIONAL,active-vt-sessions[5]SEQUENCEOFBACnetVTSessionOPTIONAL,local-time[57]TimeOPTIONAL,local-date[56]DateOPTIONAL,utc-offset[119]INTEGEROPTIONAL,daylight-savings-status[24]BOOLEANOPTIONAL,apdu-segment-timeout[10]Unsigned,apdu-timeout[11]Unsigned,number-of-APDU-retries[73]Unsigned,list-of-session-keys[55]SEQUENCEOFBACnetSessionKeyOPTIONAL,time-synchronization-recipients[116]SEQUENCEOFBACnetRecipientOPTIONAL,--requiredfortimemastermax-master[64]Unsigned(1..127)OPTIONAL,--requiredforMS/TPmaster,see12.11max-info-frames[63]UnsignedOPTIONAL,--requiredforMS/TPmaster,see12.11device-address-binding[30]SEQUENCEOFBACnetAddressBinding,database-revision[155]Unsigned,configuration-files[154]SEQUENCEOFBACnetObjectIdentifier,last-restore-time[157]BACnetTimeStamp,backup-failure-timeout[153]Unsigned16,active-cov-subscriptions[152]SEQUENCEOFBACnetCOVSubscription,max-segments-accepted[167]Unsigned,slave-proxy-enable[172]SEQUENCEOFBOOLEANOPTIONAL,auto-slave-discovery[169]SEQUENCEOFBOOLEANOPTIONAL,slave-address-binding[171]SEQUENCEOFBACnetAddressBindingOPTIONAL,manual-slave-address-binding[170]SEQUENCEOFBACnetAddressBindingOPTIONAL,profile-name[168]CharacterStringOPTIONAL}上述标记为红色者既是本次应用用到的设备属性对象ANALOG-INPUT::=SEQUENCE{object-identifier[75]BACnetObjectIdentifier,object-name[77]CharacterString,object-type[79]BACnetObjectType,present-value[85]REAL,description[28]CharacterStringOPTIONAL,device-type[31]CharacterStringOPTIONAL,status-flags[111]BACnetStatusFlags,event-state[36]BACnetEventState,reliability[103]BACnetReliabilityOPTIONAL,out-of-service[81]BOOLEAN,update-interval[118]UnsignedOPTIONAL,units[117]BACnetEngineeringUnits,min-pres-value[69]REALOPTIONAL,max-pres-value[65]REALOPTIONAL,resolution[106]REALOPTIONAL,cov-increment[22]REALOPTIONAL,time-delay[113]UnsignedOPTIONAL,notification-class[17]UnsignedOPTIONAL,high-limit[45]REALOPTIONAL,low-limit[59]REALOPTIONAL,deadband[25]REALOPTIONAL,limit-enable[52]BACnetLimitEnableOPTIONAL,event-enable[35]BACnetEventTransitionBitsOPTIONAL,acked-transitions[0]BACnetEventTransitionBitsOPTIONAL,notify-type[72]BACnetNotifyTypeOPTIONAL,event-time-stamps[130]SEQUENCEOFBACnetTimeStampOPTIONAL,--accessedasaBACnetARRAYprofile-name[168]CharacterStringOPTIONAL}ANALOG-OUTPUT::=SEQUENCE{object-identifier[75]BACnetObjectIdentifier,object-name[77]CharacterString,object-type[79]BACnetObjectType,present-value[85]REAL,description[28]CharacterStringOPTIONAL,device-type[31]CharacterStringOPTIONAL,status-flags[111]BACnetStatusFlags,event-state[36]BACnetEventState,reliability[103]BACnetReliabilityOPTIONAL,out-of-service[81]BOOLEAN,units[117]BACnetEngineeringUnits,min-pres-value[69]REALOPTIONAL,max-pres-value[65]REALOPTIONAL,resolution[106]REALOPTIONAL,priority-array[87]BACnetPriorityArray,relinquish-default[104]REAL,cov-increment[22]REALOPTIONAL,time-delay[113]UnsignedOPTIONAL,notification-class[17]UnsignedOPTIONAL,high-limit[45]REALOPTIONAL,low-limit[59]REALOPTIONAL,deadband[25]REALOPTIONAL,limit-enable[52]BACnetLimitEnableOPTIONAL,event-enable[35]BACnetEventTransitionBitsOPTIONAL,acked-transitions[0]BACnetEventTransitionBitsOPTIONAL,notify-type[72]BACnetNotifyTypeOPTIONAL,event-time-stamps[130]SEQUENCEOFBACnetTimeStampOPTIONAL,--accessedasaBACnetARRAYprofile-name[168]CharacterStringOPTIONAL}ANALOG-VALUE::=SEQUENCE{object-identifier[75]BACnetObjectIdentifier,object-name[77]CharacterString,object-type[79]BACnetObjectType,present-value[85]REAL,description[28]CharacterStringOPTIONAL,status-flags[111]BACnetStatusFlags,event-state[36]BACnetEventState,reliability[103]BACnetReliabilityOPTIONAL,out-of-service[81]BOOLEAN,units[117]BACnetEngineeringUnits,priority-array[87]BACnetPriorityArrayOPTIONAL,relinquish-default[104]REALOPTIONAL,cov-increment[22]REALOPTIONAL,time-delay[113]UnsignedOPTIONAL,notification-class[17]UnsignedOPTIONAL,high-limit[45]REALOPTIONAL,low-limit[59]REALOPTIONAL,deadband[25]REALOPTIONAL,limit-enable[52]BACnetLimitEnableOPTIONAL,event-enable[35]BACnetEventTransitionBitsOPTIONAL,acked-transitions[0]BACnetEventTransitionBitsOPTIONAL,notify-type[72]BACnetNotifyTypeOPTIONAL,event-time-stamps[130]SEQUENCEOFBACnetTimeStampOPTIONAL,--accessedasaBACnetARRAYprofile-name[168]CharacterStringOPTIONAL}BINARY-INPUT::=SEQUENCE{object-identifier[75]BACnetObjectIdentifier,object-name[77]CharacterString,object-type[79]BACnetObjectType,present-value[85]BACnetBinaryPV,description[28]CharacterStringOPTIONAL,device-type[31]CharacterStringOPTIONAL,status-flags[111]BACnetStatusFlags,event-state[36]BACnetEventState,reliability[103]BACnetReliabilityOPTIONAL,out-of-service[81]BOOLEAN,polarity[84]BACnetPolarity,inactive-text[46]CharacterStringOPTIONAL,active-text[4]CharacterStringOPTIONAL,change-of-state-time[16]BACnetDateTimeOPTIONAL,change-of-state-count[15]UnsignedOPTIONAL,time-of-state-count-reset[115]BACnetDateTimeOPTIONAL,elapsed-active-time[33]Unsigned32OPTIONAL,time-of-active-time-reset[114]BACnetDateTimeOPTIONAL,time-delay[113]UnsignedOPTIONAL,notification-class[17]UnsignedOPTIONAL,alarm-value[6]BACnetBinaryPVOPTIONAL,event-enable[35]BACnetEventTransitionBitsOPTIONAL,acked-transitions[0]BACnetEventTransitionBitsOPTIONAL,notify-type[72]BACnetNotifyTypeOPTIONAL,event-time-stamps[130]SEQUENCEOFBACnetTimeStampOPTIONAL,--accessedasaBACnetARRAYprofile-name[168]CharacterStringOPTIONAL}BINARY-OUTPUT::=SEQUENCE{object-identifier[75]BACnetObjectIdentifier,object-name[77]CharacterString,object-type[79]BACnetObjectType,present-value[85]BACnetBinaryPV,description[28]CharacterStringOPTIONAL,device-type[31]CharacterStringOPTIONAL,status-flags[111]BACnetStatusFlags,event-state[36]BACnetEventState,reliability[103]BACnetReliabilityOPTIONAL,out-of-service[81]BOOLEAN,polarity[84]BACnetPolarity,inactive-text[46]CharacterStringOPTIONAL,active-text[4]CharacterStringOPTIONAL,change-of-state-time[16]BACnetDateTimeOPTIONAL,change-of-state-count[15]UnsignedOPTIONAL,time-of-state-count-reset[115]BACnetDateTimeOPTIONAL,elapsed-active-time[33]Unsigned32OPTIONAL,time-of-active-time-reset[114]BACnetDateTimeOPTIONAL,minimum-off-time[66]Unsigned32OPTIONAL,minimum-on-time[67]Unsigned32OPTIONAL,priority-array[87]BACnetPriorityArray,relinquish-default[104]BACnetBinaryPV,time-delay[113]UnsignedOPTIONAL,notification-class[17]UnsignedOPTIONAL,feedback-value[40]BACnetBinaryPVOPTIONAL,event-enable[35]BACnetEventTransitionBitsOPTIONAL,acked-transitions[0]BACnetEventTransitionBitsOPTIONAL,notify-type[72]BACnetNotifyTypeOPTIONAL,event-time-stamps[130]SEQUENCEOFBACnetTimeStampOPTIONAL,--accessedasaBACnetARRAYprofile-name[168]CharacterStringOPTIONAL}BINARY-VALUE::=SEQUENCE{object-identifier[75]BACnetObjectIdentifier,object-name[77]CharacterString,object-type[79]BACnetObjectType,present-value[85]BACnetBinaryPV,description[28]CharacterStringOPTIONAL,status-flags[111]BACnetStatusFlags,event-state[36]BACnetEventState,reliability[103]BACnetReliabilityOPTIONAL,out-of-service[81]BOOLEAN,inactive-text[46]CharacterStringOPTIONAL,active-text[4]CharacterStringOPTIONAL,change-of-state-time[16]BACnetDateTimeOPTIONAL,change-of-state-count[15]UnsignedOPTIONAL,time-of-state-count-reset[115]BACnetDateTimeOPTIONAL,elapsed-active-time[33]Unsigned32OPTIONAL,time-of-active-time-reset[114]BACnetDateTimeOPTIONAL,minimum-off-time[66]Unsigned32OPTIONAL,minimum-on-time[67]Unsigned32OPTIONAL,priority-array[87]BACnetPriorityArrayOPTIONAL,relinquish-default[104]BACnetBinaryPVOPTIONAL,time-delay[113]UnsignedOPTIONAL,notification-class[17]UnsignedOPTIONAL,alarm-value[6]BACnetBinaryPVOPTIONAL,event-enable[35]BACnetEventTransitionBitsOPTIONAL,acked-transitions[0]BACnetEventTransitionBitsOPTIONAL,notify-type[72]BACnetNotifyTypeOPTIONAL,event-time-stamps[130]SEQUENCEOFBACnetTimeStampOPTIONAL,--accessedasaBACnetARRAYprofile-name[168]CharacterStringOPTIONAL}MULTI-STATE-INPUT::=SEQUENCE{object-identifier[75]BACnetObjectIdentifier,object-name[77]CharacterString,object-type[79]BACnetObjectType,present-value[85]Unsigned,--maximumvalueisrestrictedbythenumber-of-statesdescription[28]CharacterStringOPTIONAL,device-type[31]CharacterStringOPTIONAL,status-flags[111]BACnetStatusFlags,event-state[36]BACnetEventState,reliability[103]BACnetReliabilityOPTIONAL,out-of-service[81]BOOLEAN,number-of-states[74]Unsigned,state-text[110]SEQUENCEOFCharacterStringOPTIONAL,--accessedasaBACnetARRAYtime-delay[113]UnsignedOPTIONAL,notification-class[17]UnsignedOPTIONAL,alarm-values[7]SEQUENCEOFUnsignedOPTIONAL,fault-values[39]SEQUENCEOFUnsignedOPTIONAL,event-enable[35]BACnetEventTransitionBitsOPTIONAL,acked-transitions[0]BACnetEventTransitionBitsOPTIONAL,notify-type[72]BACnetNotifyTypeOPTIONAL,event-time-stamps[130]SEQUENCEOFBACnetTimeStampOPTIONAL,--accessedasaBACnetARRAYprofile-name[168]CharacterStringOPTIONAL}MULTI-STATE-OUTPUT::=SEQUENCE{object-identifier[75]BACnetObjectIdentifier,object-name[77]CharacterString,object-type[79]BACnetObjectType,present-value[85]Unsigned,--maximumvalueisrestrictedbythenumber-of-statesdescription[28]CharacterStringOPTIONAL,device-type[31]CharacterStringOPTIONAL,status-flags[111]BACnetStatusFlags,event-state[36]BACnetEventState,reliability[103]BACnetReliabilityOPTIONAL,out-of-service[81]BOOLEAN,number-of-states[74]Unsigned,state-text[110]SEQUENCEOFCharacterStringOPTIONAL,--accessedasaBACnetARRAYpriority-array[87]BACnetPriorityArray,relinquish-default[104]Unsigned,time-delay[113]UnsignedOPTIONAL,notification-class[17]UnsignedOPTIONAL,feedback-value[40]UnsignedOPTIONAL,event-enable[35]BACnetEventTransitionBitsOPTIONAL,acked-transitions[0]BACnetEventTransitionBitsOPTIONAL,notify-type[72]BACnetNotifyTypeOPTIONAL,event-time-stamps[130]SEQUENCEOFBACnetTimeStampOPTIONAL,--accessedasaBACnetARRAYprofile-name[168]CharacterStringOPTIONAL}MULTI-STATE-VALUE::=SEQUENCE{object-identifier[75]BACnetObjectIdentifier,object-name[77]CharacterString,object-type[79]BACnetObjectType,present-value[85]Unsigned,--maximumvalueisrestrictedbythenumber-of-statesdescription[28]CharacterStringOPTIONAL,status-flags[111]BACnetStatusFlags,event-state[36]BACnetEventState,reliability[103]BACnetReliabilityOPTIONAL,out-of-service[81]BOOLEAN,number-of-states[74]Unsigned,state-text[110]SEQUENCEOFCharacterStringOPTIONAL,--accessedasaBACnetARRAYpriority-array[87]BACnetPriorityArrayOPTIONAL,relinquish-default[104]UnsignedOPTIONAL,time-delay[113]UnsignedOPTIONAL,notification-class[17]UnsignedOPTIONAL,alarm-values[7]SEQUENCEOFUnsignedOPTIONAL,fault-values[39]SEQUENCEOFUnsignedOPTIONAL,event-enable[35]BACnetEventTransitionBitsOPTIONAL,acked-transitions[0]BACnetEventTransitionBitsOPTIONAL,notify-type[72]BACnetNotifyTypeOPTIONAL,event-time-stamps[130]SEQUENCEOFBACnetTimeStampOPTIONAL,--accessedasaBACnetARRAYprofile-name[168]CharacterStringOPTIONAL}BACnetObjectType::=ENUMERATED{accumulator(23),analog-input(0),analog-output(1),analog-value(2),averaging(18),binary-input(3),binary-output(4),binary-value(5),calendar(6),command(7),device(8),event-enrollment(9),file(10),group(11),life-safety-point(21),life-safety-zone(22),loop(12),multi-state-input(13),multi-state-output(14),multi-state-value(19),notification-class(15),program(16),pulse-converter(24),schedule(17),--seeaveraging(18),--seemulti-state-value(19),trend-log(20),--seelife-safety-point(21),--seelife-safety-zone(22),--seeaccumulator(23),--seepulse-converter(24),}上述标记为红色者即为本次应用所用到的对象类型BACnetAddressBinding::=SEQUENCE{deviceObjectIdentifierBACnetObjectIdentifier,deviceAddressBACnetAddress}BACnetAddress::=SEQUENCE{network-numberUnsigned16,--Avalueof0indicatesthelocalnetworkmac-addressOCTETSTRING--Astringoflength0indicatesabroadcast}priority-array的类型结构解释：BACnetPriorityArray::=SEQUENCESIZE(16)OFBACnetPriorityValue--accessedasaBACnetARRAYBACnetPriorityValue::=CHOICE{nullNULL,realREAL,binaryBACnetBinaryPV,integerUnsigned,constructedValue[0]ABSTRACT-SYNTAX.&Type}relinquish-default的结构BACnetBinaryPV::=ENUMERATED{inactive(0),active(1)}status-flags的类型结构：BACnetStatusFlags::=BITSTRING{in-alarm(0),fault(1),overridden(2),out-of-service(3)}Reliability的类型结构：BACnetReliability::=ENUMERATED{no-fault-detected(0),no-sensor(1),over-range(2),under-range(3),open-loop(4),shorted-loop(5),no-output(6),unreliable-other(7),process-error(8),multi-state-fault(9),configuration-error(10),}system-status的类型结构：BACnetDeviceStatus::=ENUMERATED{operational(0),operational-read-only(1),download-required(2),download-in-progress(3),non-operational(4),backup-in-progress(5),}Units的解释说明如下：BACnetEngineeringUnits::=ENUMERATED{--Electricalmilliamperes(2),amperes(3),amperes-per-meter(167),amperes-per-square-meter(168),ampere-square-meters(169),farads(170),henrys(171),ohms(4),ohm-meters(172),milliohms(145),kilohms(122),megohms(123),siemens(173),--1mhoequals1siemenssiemens-per-meter(174),teslas(175),volts(5),millivolts(124),kilovolts(6),megavolts(7),volt-amperes(8),kilovolt-amperes(9),megavolt-amperes(10),volt-amperes-reactive(11),kilovolt-amperes-reactive(12),megavolt-amperes-reactive(13),volts-per-degree-Kelvin(176),volts-per-meter(177),degrees-phase(14),power-factor(15),webers(178),--Energyjoules(16),kilojoules(17),kilojoules-per-kilogram(125),megajoules(126),watt-hours(18),kilowatt-hours(19),megawatt-hours(146),btus(20),kilo-btus(147),mega-btus(148),therms(21),ton-hours(22),--Frequencycycles-per-hour(25),cycles-per-minute(26),hertz(27),kilohertz(129),megahertz(130),per-hour(131),--Powermilliwatts(132),watts(47),kilowatts(48),megawatts(49),btus-per-hour(50),kilo-btus-per-hour(157),horsepower(51),tons-refrigeration(52),--Temperaturedegrees-Celsius(62),degrees-Kelvin(63),degrees-Kelvin-per-hour(181),degrees-Kelvin-per-minute(182),degrees-Fahrenheit(64),degree-days-Celsius(65),degree-days-Fahrenheit(66),delta-degrees-Fahrenheit(120),delta-degrees-Kelvin(121),--Timeyears(67),months(68),weeks(69),days(70),hours(71),minutes(72),seconds(73),hundredths-seconds(158),milliseconds(159),--Otherdegrees-angular(90),degrees-Celsius-per-hour(91),degrees-Celsius-per-minute(92),degrees-Fahrenheit-per-hour(93),degrees-Fahrenheit-per-minute(94),joule-seconds(183),kilograms-per-cubic-meter(186),kilowatt-hours-per-square-meter(137),kilowatt-hours-per-square-foot(138),megajoules-per-square-meter(139),megajoules-per-square-foot(140),no-units(95),newton-seconds(187),newtons-per-meter(188),parts-per-million(96),parts-per-billion(97),percent(98),percent-obscuration-per-foot(143),percent-obscuration-per-meter(144),percent-per-second(99),per-minute(100),per-second(101),psi-per-degree-Fahrenheit(102),radians(103),radians-per-second(184),revolutions-per-minute(104),square-meters-per-Newton(185),watts-per-meter-per-degree-Kelvin(189),watts-per-square-meter-degree-kelvin(141)}event-state的结构如下：BACnetEventState::=ENUMERATED{normal(0),fault(1),offnormal(2),high-limit(3),low-limit(4),life-safety-alarm(5),}protocol-services-supported的结构如下：BACnetServicesSupported::=BITSTRING{--AlarmandEventServicesacknowledgeAlarm(0),confirmedCOVNotification(1),confirmedEventNotification(2),getAlarmSummary(3),getEnrollmentSummary(4),--getEventInformation(39),subscribeCOV(5),--subscribeCOVProperty(38),--lifeSafetyOperation(37),--FileAccessServicesatomicReadFile(6),atomicWriteFile(7),--ObjectAccessServicesaddListElement(8),removeListElement(9),createObject(10),deleteObject(11),readProperty(12),readPropertyConditional(13),readPropertyMultiple(14),--readRange(35),writeProperty(15),writePropertyMultiple(16),--RemoteDeviceManagementServicesdeviceCommunicationControl(17),confirmedPrivateTransfer(18),confirmedTextMessage(19),reinitializeDevice(20),--VirtualTerminalServicesvtOpen(21),vtClose(22),vtData(23),--SecurityServicesauthenticate(24),requestKey(25),--UnconfirmedServicesi-Am(26),i-Have(27),unconfirmedCOVNotification(28),unconfirmedEventNotification(29),unconfirmedPrivateTransfer(30),unconfirmedTextMessage(31),timeSynchronization(32),--utcTimeSynchronization(36),who-Has(33),who-Is(34),}BACnetSegmentation::=ENUMERATED{segmented-both(0),segmented-transmit(1),segmented-receive(2),no-segmentation(3)}4.2.BACnet-Unconfirmed-Request-PDU结构：BACnet-Unconfirmed-Request-PDU::=SEQUENCE{pdu-type[0]Unsigned(0..15),--1forthisPDUtypereserved[1]Unsigned(0..15),--mustbesettozeroservice-choice[2]BACnetUnconfirmedServiceChoice,service-request[3]BACnet-Unconfirmed-Service-Request}BIT7BIT6BIT5BIT4BIT3BIT2BIT1BIT0PDUTYPEReservedServiceChioceServiceRequestPDUTYPE：1ServiceChioce：详见BACnetUnconfirmedServiceChoiceServiceRequest：根据BACnetConfirmedServiceChoice不同而结构不同，详见BACnet-Unconfirmed-Service-Request其它同上BACnetUnconfirmedServiceChoice::=ENUMERATED{i-Am(0),i-Have(1),unconfirmedCOVNotification(2),unconfirmedEventNotification(3),unconfirmedPrivateTransfer(4),unconfirmedTextMessage(5),timeSynchronization(6),who-Has(7),who-Is(8),utcTimeSynchronization(9)}BACnet-Unconfirmed-Service-Request::=CHOICE{i-Am[0]I-Am-Request,i-Have[1]I-Have-Request,unconfirmedCOVNotification[2]UnconfirmedCOVNotification-Request,unconfirmedEventNotification[3]UnconfirmedEventNotification-Request,unconfirmedPrivateTransfer[4]UnconfirmedPrivateTransfer-Request,unconfirmedTextMessage[5]UnconfirmedTextMessage-Request,timeSynchronization[6]TimeSynchronization-Request,who-Has[7]Who-Has-Request,who-Is[8]Who-Is-Request,utcTimeSynchronization[9]UTCTimeSynchronization-Request}I-Am-Request::=SEQUENCE{iAmDeviceIdentifierBACnetObjectIdentifier,maxAPDULengthAcceptedUnsigned,segmentationSupportedBACnetSegmentation,vendorIDUnsigned}Who-Is-Request::=SEQUENCEdeviceInstanceRangeLowLimit[0]Unsigned(0..4194303)OPTIONALdeviceInstanceRangeHighLimit[1]Unsigned(0..4194303)OPTIONAL}deviceInstanceRangeLowLimit：下限（3octor）deviceInstanceRangeHighLimit：上限（3octor）4.3.BACnet-ComplexACK-PDU结构：BACnet-ComplexACK-PDU::=SEQUENCE{pdu-type[0]Unsigned(0..15),--3forthisPDUtypesegmented-message[1]BOOLEAN,more-follows[2]BOOLEAN,reserved[3]Unsigned(0..3),--mustbesettozeroinvokeID[4]Unsigned(0..255),sequence-number[5]Unsigned(0..255)OPTIONAL,--onlyifsegmentproposed-window-size[6]Unsigned(1..127)OPTIONAL,--onlyifsegmentservice-ACK-choice[7]BACnetConfirmedServiceChoice,service-ACK[8]BACnet-Confirmed-Service-ACK}BIT7BIT6BIT5BIT4BIT3BIT2BIT1BIT0PDUTYPESEGMOR0OriginalInvokeIDSequenceNumber(onlypresentbySEG==1)ProposedWindowSize(onlypresentbySEG==1)ServiceAckChioceServiceACKPDUTYPE：1ServiceAckChioce：详见BACnetConfirmedServiceChoiceServiceACK：根据BACnetConfirmedServiceChoice不同而结构不同，详见BACnet-Confirmed-Service-ACK其它同上BACnet-Confirmed-Service-ACK::=CHOICE{--AlarmandEventServicesgetAlarmSummary[3]GetAlarmSummary-ACK,getEnrollmentSummary[4]GetEnrollmentSummary-ACK,getEventInformation[29]GetEventInformation-ACK,--FileAccessServicesatomicReadFile[6]AtomicReadFile-ACK,atomicWriteFile[7]AtomicWriteFile-ACK,--ObjectAccessServicescreateObject[10]CreateObject-ACK,readProperty[12]ReadProperty-ACK,readPropertyConditional[13]ReadPropertyConditional-ACK,readPropertyMultiple[14]ReadPropertyMultiple-ACK,readRange[26]ReadRange-ACK,--RemoteDeviceManagementServicesconfirmedPrivateTransfer[18]ConfirmedPrivateTransfer-ACK,--VirtualTerminalServicesvtOpen[21]VT-Open-ACK,vtData[23]VT-Data-ACK,--SecurityServicesauthenticate[24]Authenticate-ACK}ReadProperty-ACK::=SEQUENCE{objectIdentifier[0]BACnetObjectIdentifier,propertyIdentifier[1]BACnetPropertyIdentifier,propertyArrayIndex[2]UnsignedOPTIONAL,--usedonlywitharraydatatypepropertyValue[3]ABSTRACT-SYNTAX.&Type}ReadPropertyMultiple-ACK::=SEQUENCE{listOfReadAccessResultSEQUENCEOFReadAccessResult}ReadAccessResult::=SEQUENCE{objectIdentifier[0]BACnetObjectIdentifier,listOfResults[1]SEQUENCEOFSEQUENCE{propertyIdentifier[2]BACnetPropertyIdentifier,propertyArrayIndex[3]UnsignedOPTIONALreadResultCHOICE{propertyValue[4]ABSTRACT-SYNTAX.&Type,propertyAccessError[5]Error}}OPTIONAL}4.4.BACnet-Error-PDU结构：BACnet-Error-PDU::=SEQUENCE{pdu-type[0]Unsigned(0..15),--5forthisPDUtypereserved[1]Unsigned(0..15),--mustbesettozerooriginal-invokeID[2]Unsigned(0..255),error-choice[3]BACnetConfirmedServiceChoice,error[4]BACnet-Error}BIT7BIT6BIT5BIT4BIT3BIT2BIT1BIT0PDUTYPE0OriginalInvokeIDErrorChoiceError。。。。PDUTYPE：5OriginalInvokeID：调用者IDErrorChioce：详见BACnetConfirmedServiceChioceError：根据ErrorChioce不同而不同，详见BACnet-ErrorBACnet-Error::=CHOICE{other[127]Error,--AlarmandEventServicesacknowledgeAlarm[0]Error,confirmedCOVNotification[1]Error,confirmedEventNotification[2]Error,getAlarmSummary[3]Error,。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。--ObjectAccessServicesaddListElement[8]ChangeList-Error,removeListElement[9]ChangeList-Error,createObject[10]CreateObject-Error,deleteObject[11]Error,readProperty[12]Error,readPropertyConditional[13]Error,readPropertyMultiple[14]Error,readRange[26]Error,writeProperty[15]Error,writePropertyMultiple[16]WritePropertyMultiple-Error,--RemoteDeviceManagementServicesdeviceCommunicationControl[17]Error,confirmedPrivateTransfer[18]ConfirmedPrivateTransfer-Error,confirmedTextMessage[19]Error,。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。}Error::=SEQUENCE{error-classENUMERATED{device(0),object(1),property(2),resources(3),security(4),services(5),vt(6),},error-codeENUMERATED{other(0),authentication-failed(1),character-set-not-supported(41),invalid-array-index(42),invalid-configuration-data(46),invalid-data-type(9),unknown-property(32),}}5、BACnetAPDU可变部分的编码这部分的数据编码通常分为两个部分：数据类型描述部分和数据部分。描述部分主要描述接下来的数据是什么类型，如何编码，所占长度等信息；关于这部分需要详细的说明如下：首先描述部分含有一个Tags，主要分为两类：应用Tag和上下文Tag，前者的结构如下：BIT7---BIT4Bit3Bit2—Bit0TagnumberClassLength/Value/TypeTagnumber:指出了数据的类型（0-14只占据4位数据，当高四位置为‘1111’时表示接下来的一个字节作为Tag的描述）Class：0时表示数据位应用数据类型，1表示上下文数据类型；此种情况下TagNumber为上下文TagLength/Value/Type：当（0-4）时表示数据的长度，当为’101’时表示后边的octor代表数据的长度.如果为’110’表示为一个openingtag,那么必然需要一个closeingTag(‘111’)Applicationtags:0:NULL1:Boolean2:unsignedinteger3:signedinterger4:Real(ASNSI/IEEE-754)5：Double（ANSI/IEEE-754doubleprecisionfloatingpoint）6：octorstring7：Characterstring8：Bitstring9：Enumerated10：Date11：Time12：BACnetObjectIdentifierContext-specialtags：含有一个contexttag如其位于结构中的第一个contexttag则为1，第二个contexttag则为2Example:Application-taggednullvalueASN.1=NULLApplicationTag=Null(TagNumber=0)EncodedTag=X\'00\'Example:Application-taggedBooleanvalue（Boolean编码在一个字节中）ASN.1=BOOLEANValue=FALSEApplicationTag=Boolean(TagNumber=1)EncodedTag=X\'10\'Example:Context-taggedBooleanvalue（上下文Boolean的编码）ASN.1=[2]BOOLEANValue=TRUEContextTag=2EncodedTag=X\'29\'EncodedData=X\'01\'Example:Application-taggedunsignedintegerASN.1=UnsignedValue=72ApplicationTag=UnsignedInteger(TagNumber=2)EncodedTag=X\'21\'EncodedData=X\'48\'Example:Application-taggedsignedintegerASN.1=INTEGERValue=72ApplicationTag=SignedInteger(TagNumber=3)EncodedTag=X\'31\'EncodedData=X\'48\'Example:Application-taggedsingleprecisionrealASN.1=REALValue=72.0ApplicationTag=Real(TagNumber=4)EncodedTag=X\'44\'EncodedData=X\'42900000\'Example:Application-taggeddoubleprecisionreal（双精度占用8字节）ASN.1=DoubleValue=72.0ApplicationTag=Double(TagNumber=5)EncodedTag=X\'55\'ExtendedLength=X\'08\'EncodedData=X\'4052000000000000\'Example:Application-taggedoctetstringASN.1=OCTETSTRINGValue=X\'1234FF\'ApplicationTag=OctetString(TagNumber=6)EncodedTag=X\'63\'EncodedData=X\'1234FF\'Theinitialoctetshallspecifythecharactersetwiththefollowingencoding:X\'00\'ANSIX3.4X\'01\'IBM™/Microsoft™DBCSX\'02\'JISC6226X\'03\'ISO10646(UCS-4)X\'04\'ISO10646(UCS-2)X\'05\'ISO8859-1Example:Application-taggedcharacterstringASN.1=CharacterStringValue="ThisisaBACnetstring!"(ANSIX3.4)ApplicationTag=CharacterString(TagNumber=7)EncodedTag=X\'75\'LengthExtension=X\'19\'CharacterSet=X\'00\'(ANSIX3.4)EncodedData=X\'546869732069732061204241436E657420737472696E6721\'Example:Application-taggedcharacterstring(DBCS)ASN.1=CharacterStringValue="ThisisaBACnetString!"(IBM/MicrosoftDBCS,codepage850)ApplicationTag=CharacterString(TagNumber=7)EncodedTag=X\'75\'LengthExtension=X\'1B\'EncodedData=X\'010352546869732069732061204241436E657420737472696E6721\'不再举例，本程序使用(ANSIX3.4)类型的字符串编码Example:Application-taggedbitstringASN.1=BITSTRINGValue=B\'10101\'ApplicationTag=BitString(TagNumber=8)EncodedTag=X\'82\'EncodedData=X\'03A8\'Example:Application-taggedenumerationASN.1=BACnetObjectTypeValue=ANALOG-INPUT(0)ApplicationTag=Enumerated(TagNumber=9)EncodedTag=X\'91\'EncodedData=X\'00\'Example:Application-taggeddatevalueASN.1=DateValue=January24,1991(Dayofweek=Thursday)ApplicationTag=Date(TagNumber=10)EncodedTag=X\'A4\'EncodedData=X\'5B011804\'Example:Application-taggedtimevalueASN.1=TimeValue=5:35:45.17P.M.=17:35:45.17ApplicationTag=Time(TagNumber=11)EncodedTag=X\'B4\'EncodedData=X\'11232D11\'Example:Application-taggedobjectidentifiervalueASN.1=ObjectIdentifierValue=(BinaryInput,15)ApplicationTag=ObjectIdentifier(TagNumber=12)EncodedTag=X\'C4\'EncodedData=X\'00C0000F\'Context-specialtags：Example:Context-taggednullvalueASN.1=[3]NULLContextTag=3EncodedTag=X\'38\'Example:Context-taggedBooleanvalueASN.1=[6]BOOLEANValue=FALSEContextTag=6EncodedTag=X\'69\'EncodedData=X\'00\'Example:Context-taggedunsignedintegerASN.1=[0]UnsignedValue=256ContextTag=0EncodedTag=X\'0A\'EncodedData=X\'0100\'Example:Context-taggedsignedintegerASN.1=[5]INTEGERValue=-72ContextTag=5EncodedTag=X\'59\'EncodedData=X\'B8\'Example:Context-taggedsingleprecisionrealASN.1=[0]REALValue=-33.3ContextTag=0EncodedTag=X\'0C\'EncodedData=X\'C2053333\'Example:Context-taggeddoubleprecisionrealASN.1=[1]DoubleValue=-33.3ContextTag=1EncodedTag=X\'1D\'ExtendedLength=X\'08\'EncodedData=X\'C040A66666666666\'Example:Context-taggedoctetstringASN.1=[1]OctetStringValue=X\'4321\'ContextTag=1EncodedTag=X\'1A\'EncodedData=X\'4321\'Example:Context-taggedcharacterstringASN.1=[5]CharacterStringValue="ThisisaBACnetstring!"(ANSIX3.4)ContextTag=5EncodedTag=X\'5D\'LengthExtension=X\'19\'CharacterSet=X\'00\'(ANSIX3.4)EncodedData=X\'546869732069732061204241436E657420737472696E6721\'Example:Context-taggedbitstringASN.1=[0]BITSTRINGValue=B\'10101\'ContextTag=0EncodedTag=X\'0A\'UnusedBitsinLastOctet=X\'03\'EncodedData=X\'A8\'Example:Context-taggedenumerationASN.1=[9]BACnetObjectTypeValue=ANALOG-INPUT(0)ContextTag=9EncodedTag=X\'99\'EncodedData=X\'00\'Example:Context-taggeddatevalueASN.1=[9]DateValue=January24,1991(Dayofweek=Thursday)ContextTag=9EncodedTag=X\'9C\'EncodedData=X\'5B011805\'Example:Context-taggedtimevalueASN.1=[4]TimeValue=5:35:45.17P.M.=17:35:45.17ContextTag=4EncodedTag=X\'4C\'EncodedData=X\'11232D11\'Example:Context-taggedobjectidentifiervalueASN.1=[4]ObjectIdentifierValue=(BinaryInput,15)ContextTag=4EncodedTag=X\'4C\'EncodedData=X\'00C0000F\'6、通讯步骤描述数据通讯的步骤，以此作为描述文档进行备份及参考。本次应用数据通讯主要分为如下几步：\uf0d8IED设备发送广播命令，查询网络中的BACnet设备；通讯机（实现BACnet）接收到命令后，同样回应一条广播命令，告诉IED自己属于BACnet设备\uf0d8IED开始点对点通讯，查询设备属性；通讯机应答复杂回应（命令的一种），送上属性信息或者回应属性不存在的错误应答\uf0d8IED开始召唤设备的所具备的数据对象的属性（ID、名称等）；通讯机应答这些数据对象信息（对象ID、名称等）或者错误的对象不存在应答\uf0d8IED开始召唤数据对象的值；通讯局送上某个或某些数据对象的数据信息或一些属性信息接下来进行报文举例说明：6.1.广播查找设备命令810B000C0120FFFF00FF10080000-00000000解释：81：B/IP虚拟协议的标示0B：广播通信000C：长度0120FFFF00FF为NPDU部分，见NPDU部分报文的说明如下：01：网络层的版本20：表明目标网络信息存在FFFF：DNET设为0xFFFF表示广播00：DLEN为0，表示DADR不存在，广播报文FF：HopCount在这里需设置为FF1008000000000000：此为APDU部分，详见解释如下：10：表示无需确认的请求信息08：类型为WHO-IS00（6个）：表示网络地址的范围不限810B00180120FFFF00FF1000C402-0012BD2205B291032125此报文是上面报文的应答这里的类型为00，及时I-AM的意思，紧接的报文为I-AM-REQUEST的格式，参照第四章及第五章的内容。6.2.读取某一设备信息810A0011010402045F0C0C020012-BD196100读取ID为0x02BD设备的属性（0x61）810A001A0100305F0C0C020012BD19613E850601000B0030603F回答上述属性，这里的回应格式根据所要属性的格式进行组织。详见第五章810A001D01040204600E0C020012-BD1E0979096B0978094D097009461F读取ID为0x02BD设备的多个属性（0x790x6B0x780x4D0x700x46）810A006A010030600E0C020012BD-1E29794E7519004669656C6453657276-657220546563686E6F6C6F676965734F-296B4E91034F29784E21254F294D4E75-1100496E74656772615F313633305F42-434E4F29704E91004F29464E750C0050-726F746F436573736F724F1F上述报文的应答格式，详见第五章的内容810A001201040204610C0C020012-BD1A08F3读取属性0x08F3，由于不存在此属性，故报错如下810A000D010050610C9102912000-00000000810A001301040204620C0C020012-BD194C2900读取设备的object_list，带有数值下标（0x2900）,第一个先回答object的个数，然后才开始每个对象。回应如下：810A0016010030620C0C020012BD-194C29003E21453F810A001301040204630C0C020012-BD194C2901再次读取设备的object_list，此为第一个对象，回答为device的ID，然后才是设备的数据对象810A0019010030630C0C020012BD-194C29013EC4020012BD3F810A001301040204640C0C020012-BD194C2902读取设备的第一个数据对象。810A0019010030640C0C020012BD-194C29023EC4008000C83F回答第一个数据对象的ID信息6.3.读取数据信息810A001101040204650C0C008000-C8194D00读取analog-value对象的名称属性810A0024010030650C0C008000C8-194D3E7510005365745F6E6F64655F6F-66667365743F回答analog-value对象的名称810A001701040204730E0C000000-0F1E09750955096F1F读取analog-input的多个属性810A0026010030730E0C0000000F-1E29754E910B4F29554E44000000004F-296F4E8204004F1F回答analog-input的属性询问其它的数据访问方式基本相同的道理，至于报文格式的细节解释详见第四、五章的内容',)