CIRCUTOR CVM-B Series - Manual (Page 178)

6�2�1�- example of MODBUS query
Query: Instantaneous value of the L1 phase voltage
Address function
Initial reg-
ister
No� of regis-
ters
CRC
0A 04 0000 0002 70B0
Address: 0A, Peripheral number: 10 in decimal.
function: 04, Read function.
Initial Register: 0000, register from which to start reading.
No� of registers: 0002, number of registers to be read.
CRC: 70B0, CRC character.
Response:
Address function
No� of
Bytes
Register
no� 1
Register
no� 2
CRC
0A 04 04 0000 084D 8621
Address: 0A, Responding peripheral number: 10 in decimal.
function: 04, Read function.
No� of bytes: 04, No. of bytes received.
Register: 0000084D, value of the L1 phase voltage: VL1 x 10: 212.5 V
CRC: 8621, CRC character.
6.3.- MODBUS MEMORY MAP
All MODBUS map addresses are hexadecimal.
6�3�1�- Measurement Variables
For these variables function 0x04 is implemented: reading registers.
Each instantaneous value occupies 2 registers.
The maximum and minimum values occupy 4 registers, 2 for the variable value while the next
two indicate the date and time when the maximum or minimum value was read, in compact
format (U32).
The short format of the register date and time is:
Bit
32
Bits
31 ��� 27
Bits
26���23
Bits
22���18
Bits
17���13
Bits
12���7
Bits
6���1
x Year Month Day Hour Minutes seconds
The year is calculated with the offset = 2013, that is the
Real Year : 2013 + Year ( bits 31 ...27) .
Each unit occupies a separate register.
178
CVM-B100 - CVM-B150
Instruction Manual