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LM P RS485 Data Logger
8.5
R
EAD
C
URRENT
P
RESSURE
D
ATA IN
RTU
MODE
To read the current pressure data from the LM P RS485 data logger, the function code is
0x03(hex). The register address for accessing the current pressure data is 0x0050 (hex)
and number of registers required is 0x0002(hex).
The Query request format for reading current pressure data is as below:
Field Name
Value (hex)
Description
Device Address
0x60
Value between 0x01 to 0xF7 (1 t o247)
Function code
0x03
Read holding registers
Start address High
0x00
Most significant byte of start address
Start address Low
0x50
Least significant byte of start address
Number of Registers High
0x00
Most significant byte of Number of registers
Number of Registers Low
0x02
Most significant byte of Number of registers
Error Check
0xCC6B
2 Byte CRC
The normal Query response format for the read current pressure data request is as below:
Field Name
Value (hex)
Description
Device Address
0x60
Value between 0x01 to 0xF7 (1 t o247)
Function code
0x03
Read holding registers
Byte Count
0x04
Number of bytes
Data Register High
0x3D
Most significant byte of data requested
Data Register Low
0x1C
Least significant byte of data requested
Data Register High
0x40
Most significant byte of data requested
Data Register Low
0x00
Least significant byte of data requested
Error Check
0x
775F
2 Byte CRC
Colored bytes in the response shows the pressure current data as float value (4 bytes).
Here, 0x3D1C4000 (hex) = 0.038 (decimal), this shows the current pressure in pascal at
with zero pressure input to the sensor.
The current pressure data query request and response is shown in table below.
Table 7 MEI Current pressure data query
Read data Device
Id (hex)
Function
code
(hex)
Address
(hex)
No. of Registers
Query
Request
Query Response
High
(hex)
Low
(hex)
Current
Pressure
Data
60
03
00B0
00
01
60030050000
2CC6B
600304
3D1C4000
775F
Colored byte in response is the value of the registers requested.
Summary of Contents for LM Pro 63 Series
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