57
6.3.2
Modbus Frame Encapsulation
6.3.3
Additional Address Definition
6.3.4 Function Code
Description
2
.Broadcast is only for command write and not for read.
Note:
X
1.
means the address of HEP-2300 ( which can be assigned by the
rotary switch
address
, range from 0 ~ 3)
Modbus RTU consists of Additional Address, Function Code, Data
and Error Check.
Additional address is the slave ID of the device. Each HEP-2300 unit
should have their unique and own device address to communicate
over the bus.
The main purpose of the function codes is to tell the slave what
kind of action to perform. For example: Function code 03 will
query the slave to read
with the
holding registers and respond
master their contents.
Additional address (1byte)：
defines PSU/Charger slave ID.
Function code (1byte)：
what
The function code is used to tell the slave
kind of action to perform.
Data (N bytes):For data exchange, contents and data length are
dependent on different function codes.
Error Check (2bytes)：
utilizes CRC-16.
Additional Address
1 byte
Function Code
Slave ID
1 byte
0x8X
0x03
0x00
0x04
0x06
Data
Description
N bytes
X mean device address (defined by Address
)
rotary switch
Read Holding Register
Read Input Register
Preset Single Register
Broadcast
Error Check
2 bytes
Code
Function Code
1
3
4
2
Device
No.
Position
of switch
0
1
1
2
2
3
3
4
6
58
FC = 06
FC = 03/04
The following is data description of register addresses.
2 Bytes
2 Bytes
Register Address
Register Value
Register
address
0x0000
0x0020
0x0030
0x0040
0x0050
0x0060
0x0061
0x0062
0x0080~
0x0082
0x0083~
0x0085
0x0086~
0x0088
0x03、0x06
0x03、0x06
0x03、0x06
0x03
0x04
0x04
0x04
0x04
0x03
0x03
0x03
1
2
2
2
2
2
2
2
6
6
6
OPERATION
VOUT_SET
IOUT_SET
FAULT_STATUS
READ_VIN
READ_VOUT
READ_IOUT
READ
TEMPERATURE_1
MFR_ID_B0B5
MFR_ID_B6B11
MFR_MODEL_
B0B5
Command
Name
Function
code
# of data
Bytes
Description
Remote ON/OFF control
ON: 0x0001
OFF: 0x0000
Output voltage set
(format: value, F=0.01)
Output current set
(format: value, F=0.01)
Abnormal status
Input voltage read value
(format: value, F=0.1)
Output voltage read value
(format: value, F=0.01)
Output current read value
(format: value, F=0.01)
Internal ambient
temperature
(format: value, F=0.1)
Manufacture s name
'
Manufacture s name
'
Manufacture model name
6.3.5
Data Field and Command Lists
Data field provides additional information by the slave to
complete the action specified by the function code(
) in a
FC
request. The data field typically includes register addresses,
count values, and written data. There are several forms according
to the function codes.
Quantity of (Input) Registers
2 Bytes
2 Bytes
Starting Address
6