1) How Driver Maps Uplink ASDU to Point

NG Gateway IEC104 driver internally uses (typeId, ioa) as key to match points:

• typeId: ASDU TypeID in point configuration (u8)
• ioa: Information Object Address in point configuration

Therefore:

• Same IOA under different TypeID are different points
• If you configure Point TypeID wrong, even if IOA is correct, data will not be matched

2) How to Choose DataType for Common Uplink Types (M_*)

Single Point (M_SP_*)

Semantics: Switch/Status (1 bit) Recommendation:

• DataType = Boolean

Double Point (M_DP_*)

Semantics: Double point status, usually value 0..3 (e.g., Intermediate/On/Off/Indeterminate, specific to protocol) Recommendation:

• DataType = UInt8 (Preserve raw semantics)
• Or map 0..3 to business enum in edge computing layer (More readable)

32bit Bit String (M_BO_*)

Semantics: 32-bit bit string (e.g., Fault Word, Alarm Word) Recommendation:

• DataType = UInt32

Telemetry (M_ME_*)

IEC104 Telemetry has multiple expressions:

• Normalized (M_ME_NA/ND)
• Scaled (M_ME_NB)
• Short Float (M_ME_NC)

Recommendation:

• Prioritize consistency with field RTU/Master Station agreement
• For "Engineering Value" telemetry, recommend Float32/Float64, combined with scale for unit conversion

Integrated Totals (M_IT_*)

Semantics: Energy/Cumulative Count Recommendation:

• DataType = Int64 or UInt64

3) Value Type Requirements for Write Command Types (C_*)

When writing (WritePoint / Action Parameter), the driver will force convert input value to target type according to Command TypeID:

• C_SC_*: bool
• C_DC_*: u8
• C_RC_*: u8
• C_SE_* (NA/NB): i16
• C_SE_* (NC): f32
• C_BO_*: i32

Best Practice

Point/Parameter data_type should be consistent with command semantics, so core type validation and driver conversion will be more predictable.

4) How to Model CA (Common Address)

CA is modeled as Device configuration:

• One CA One Device is the most common practice
• When multiple CAs exist on the same TCP link, create multiple Devices sharing one Channel