Iskra WM3M4 - Signature Algorithm; Entering Billing Dataset; Transaction Commands

DIGITAL SIGNATURE (VALID ONLY FOR WM3M4C)
User’s Manual WM3M4 &WM3M4C
37
6.5.6 Signature algorithm
Energy meter currently supports only ECDSA-secp256r1-SHA256 algorithm.
Register 47060:
Value
Signature format
0
Without signature
4
ECDSA-secp256r1-SHA256
Table 14: Signature algorithm
6.5.7 Entering billing dataset
Dataset register is at MODBUS address 47100. Only 120 MODBUS registers (240 bytes) can be entered
in one write command. Maximum size of billing dataset is 1024 bytes. Format is defined in Dataset
format paragraph.
Example:
If 300 bytes need to be written:
 write 120 MODBUS registers to MODBUS address 47100
 write 30 registers to MODBUS address 47220 (47100 + 120).
After writing dataset, length (in bytes) must be written to MODBUS address 47056.
6.5.8 Transaction commands
Command register for transactions is at MODBUS address 47051. High 8 bits is command, lower 8 bits
are reserved.
It is very important to check measurement status register (47000) before sending command,
because energy meter accepts only commands which are valid for current state.
Time, input message and input message length must be set before sending command.
After sending command, check result of operation in control status register (47052).
Register 47051
Value
Command
Valid charging states (47000)
‘B’ (0x42)
Begin measurement
Idle state (0)
‘E’ (0x45)
‘L’ (0x4C)
‘R’ (0x52)
‘A’ (0x41)
‘P’ (0x50)
End measurement
Active state
‘C’ (0x43)
Intermediate Reading
Active state
‘X’ (0x58)
eXception
Active state
‘T’ (0x54)
Tariff Change
Active state
‘S’ (0x53)
Suspended command
Active state
‘r’ (0x72)
End measurement (with
begin and end)
Active state
‘f’ (0x66)
Fiscal Reading
Any state
‘h’ (0x68)
Hold command
Active state
Table 15: Transaction commands