D-2 B90 Low Impedance Bus Differential System GE MultilinD.1 IEC 60870-5-104 APPENDIX DDWhen using an unbalanced link layer, the following Application Service Data Unit (ASDU) types are returned in class 2messages (low priority) with the indicated causes of transmission: The standard assignment of ASDUs to class 2 messages is used as follows: A special assignment of ASDUs to class 2 messages is used as follows:5. APPLICATION LAYERTransmission Mode for Application Data:Mode 1 (least significant octet first), as defined in Clause 4.10 of IEC 60870-5-4, is used exclusively in this companionstandard.Common Address of ASDU: One Octet Two OctetsInformation Object Address: One Octet Structured Two Octets Unstructured Three OctetsCause of Transmission: One Octet Two Octets (with originator address). Originator address is set to zero if not used.Maximum Length of APDU: 253 (the maximum length may be reduced by the system.Selection of standard ASDUs:For the following lists, the boxes indicate the following: – used in standard direction; – not used; – cannot beselected in IEC 60870-5-104 standard.Process information in monitor direction <1> := Single-point information M_SP_NA_1 <2> := Single-point information with time tag M_SP_TA_1 <3> := Double-point information M_DP_NA_1 <4> := Double-point information with time tag M_DP_TA_1 <5> := Step position information M_ST_NA_1 <6> := Step position information with time tag M_ST_TA_1 <7> := Bitstring of 32 bits M_BO_NA_1 <8> := Bitstring of 32 bits with time tag M_BO_TA_1 <9> := Measured value, normalized value M_ME_NA_1 <10> := Measured value, normalized value with time tag M_NE_TA_1 <11> := Measured value, scaled value M_ME_NB_1 <12> := Measured value, scaled value with time tag M_NE_TB_1 <13> := Measured value, short floating point value M_ME_NC_1 <14> := Measured value, short floating point value with time tag M_NE_TC_1 <15> := Integrated totals M_IT_NA_1 <16> := Integrated totals with time tag M_IT_TA_1 <17> := Event of protection equipment with time tag M_EP_TA_1 <18> := Packed start events of protection equipment with time tag M_EP_TB_1 <19> := Packed output circuit information of protection equipment with time tag M_EP_TC_1 <20> := Packed single-point information with status change detection M_SP_NA_1
