Addressing

Monitor ASDUs

To determine the address representing the information object in the monitor direction, use the following template:

ASDU_TYPE.IOA.Option[,Read=1], where ASDU_TYPE specifies the type of the represented ASDU (see below), 
IOA specifies the address of the information object, 
Option specifies the attribute represented by the address (see below), 
and the Read=1 (optional) descriptor indicates that the value must be 
requested periodically by sending the command C_RC_NA_1

The Read=1 specifier affects the request procedure if the Enable Reads parameter of the device is set to True.

The table below lists the possible values for ASDU_TYPE.

ASDU_TYPE	ASDU	Description
M_SP	M_SP_NA_1, M_SP_TA_1, M_SP_TB_1	Single-point information.
M_DP	M_DP_NA_1, M_DP_TA_1, M_DP_TB_1	Double-point information.
M_ST	M_ST_NA_1, M_ST_TA_1, M_ST_TB_1	Step position information.
M_BO	M_BO_NA_1, M_BO_TA_1, M_BO_TB_1	Bit string of 32 bit.
M_ME_NV	M_ME_NA_1, M_ME_TA_1, M_ME_TD_1	Measured value normalized. This represents a value between -1 and 0.999969482421875.
M_ME_SV	M_ME_NB_1, M_ME_TB_1, M_ME_TE_1	Measured value scaled. Possible values are -32768 to 32767.
M_ME_FV	M_ME_NC_1, M_ME_TC_1, M_ME_TF_1	Measured value short floating point number.
M_IT	M_IT_NA_1, M_IT_TA_1, M_IT_TB_1	Integrated totals. Read=1 specifier is not supported for this ASDU type.

The table below lists the possible values for Option.

Option	Supported ASDU_TYPE	Description
Value	All types	Represents the value of the information object. If the IV (invalid) bit is set in the quality descriptor of the information object, the tag will go to the Bad state.
COT	All types	Represents the ASDU cause of transmission field.
Quality	All types	Represents the quality descriptor of the information object as a number.
Timestamp	All types	Represents the timestamp CP56Time2a (without any conversion) of the information object. If the information object does not contain a timestamp, the tag will take the value 0001-01-01 00:00:00 and go to the Bad state.
Transient	Only for M_ST	Specifies whether M_ST is in transient state.
SQ	Only for M_IT	Represents the M_IT sequence number.

Note that if the information object contains the timestamp CP56Time2a, it will be used as the timestamp of the tag (taking into account the time zone of the station), otherwise the time ASDU arrival to the server will be used.

It should also be noted that for buffered ASDUs (containing several states of the same information object), the “last” state of the information object will be used as the resulting tag state, but the entire sequence of states will be written to the store (for example, InfluxDB), if such feature is used.

Examples of allowed addresses in the monitor direction:

• M_SP.1.COT

• M_SP.62.Quality,Read=1

• M_SP.40.Timestamp,Read=1

• M_SP.1.Value

• M_ME_SV.1.Value,Read=1

• M_BO.1.Value,Read=1

• M_IT.9.Value

• M_ME_FV.1.Value

Control ASDUs

To determine the address representing the information object in the control direction, use the following template:

ASDU_TYPE.IOA.Option[.SubOption][.Timestamp], where ASDU_TYPE specifies 
the type 
of the control command (see below), 
IOA defines the address of the information object, 
Option specifies the purpose of the command (see below), 
SubOption (optional) specifies the duration of the command, 
Timestamp (optional) indicates that a timestamp must be sent along 
with the command (the time zone set for the station affects the timestamp generation)

The table below lists the possible values for ASDU_TYPE.

ASDU_TYPE	ASDU	Description
C_SC	C_SC_NA_1, C_SC_TA_1	Single command. Possible values are True or False
C_DC	C_DC_NA_1, C_DC_TA_1	Double command. Possible values are 1 or 2.
C_RC	C_RC_NA_1, C_RC_TA_1	Step command. Possible values are 1 or 2.
C_SE_NV	C_SE_NA_1, C_SE_TA_1	Set point command (normalized value). Possible values are -1 to 0.999969482421875.
C_SE_SV	C_SE_NB_1, C_SE_TB_1	Set point command (scaled value). Possible values are -32768 to 32767.
C_SE_FV	C_SE_NC_1, C_SE_TC_1	Set point command (short value).
C_BO	C_BO_NA_1, C_BO_TA_1	Bit string of 32 bit.

The table below lists the possible values for Option.

Option	Supported ASDU_TYPE	Description
Execute	All types	Indicates that the control command is executed in one step.
Select	All types except C_BO	The first step of the two-step value writing process known as “select before operation”. The command is executed with the help of sending the Execute command for the same information object.
Deselect	All types except C_BO	Resets the selection command to the initial stage before execution, if a selection has been made for it.

The table below lists the possible values for SubOption.

SubOption	Supported ASDU_TYPE	Description
ShortPulse	C_SC, C_DC, C_RC	The value of the command specifier will be set to 1.
LongPulse	C_SC, C_DC, C_RC	The value of the command specifier will be set to 2.
Persistent	C_SC, C_DC, C_RC	The value of the command specifier will be set to 3.

Examples of allowed addresses in the control direction:

• C_SC.1.Execute

• C_DC.15.Select.ShortPulse

• C_DC.1.Select.Timestamp

• C_SC.73.Select.ShortPulse.Timestamp

• C_SC.1.Select.Persistent

• C_SC.3219.Deselect.LongPulse

• C_SC.1.Deselect.Persistent