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