for compatibility with some SCADA systems, SDM630Modbus Smart meter will response to
any single input or holding register read with an instrument type specific value.
The SDM630Modbus can transfer a maximum of 40 values in a single transaction; therefore
the maximum number of registers requestable is 80. Exceeding this limit prompts the
SDM630Modbus to generate an exception response.
Data transmission speed is selectable between 2400, 4800, 9600, 19200, 38400 baud.
1.2 Input register
Input registers are used to indicate the present values of the measured and calculated
electrical quantities. Each parameter is held in two consecutive16 bit register.The following
table details the 3X register address, and the values of the address bytes within the message.
A (*) in the column indicates that the parameter is valid for the particular wiring system. Any
parameter with a cross(X) will return the value zero. Each parameter is held in the 3X registers.
Modbus Protocol function code 04 is used to access all parameters.
For example, to request: Amps 1 Start address=0006
No. of registers =0002
Amps 2 Start address=0008
No. of registers=0002
Each request for data must be restricted to 40 parameters or less. Exceeding the 40
parameter limit will cause a Modbus Protocol exception code to be returned.
1.2.1 SDM630Modbus Input Registers
Address
(Register)
Parameter
Number
SDM630Modbus Input Register
Parameter
Modbus
Protocol
Start
Address
Hex
3
Ø
3
Ø
1
Ø
Description
Units
Hi
Byte
Lo
Byte
4
W
3
W
2
W
30001
1
Phase 1 line to neutral volts.
Volts
00
00
√
X
√
30003
2
Phase 2 line to neutral volts.
Volts
00
02
√
X
X
30005
3
Phase 3 line to neutral volts.
Volts
00
04
√
X
X
30007
4
Phase 1 current.
Amps
00
06
√
√
√
30009
5
Phase 2 current.
Amps
00
08
√
√
X
30011
6
Phase 3 current.
Amps
00
0A
√
√
X
30013
7
Phase 1 power.
Watts
00
0C
√
X
√
30015
8
Phase 2 power.
Watts
00
0E
√
X
√
30017
9
Phase 3 power.
Watts
00
10
√
X
X
30019
10
Phase 1 volt amps.
VA
00
12
√
X
√
30021
11
Phase 2 volt amps.
VA
00
14
√
X
X
30023
12
Phase 3 volt amps.
VA
00
16
√
X
X
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