P30P-09A 49 User's manual
●
Baud rate: 4800, 9600, 19200, 38400, 57600, 115200, 230400, 256000 [b/s].
●
Operating mode: RTU frame format: 8n2, 8e1, 8o1, 8n1.
●
Maximum response
time: 200 ms
(time until the response start can be extended up to 500ms during writing to a
SD/SDH
C card or to the file system internal memory
)
.
Configuration of the serial link parameters consists of determining the baud rate, the device
address and the format of the transmission mode - protocol.
Note:
Each transmitter connected to the communication network must:
●
have a unique address, different from the addresses of other devices connected to the network.
●
Identical baud rate and a type of transmission mode
5.9.3 Description of the implemented functions
The following functions of the MODBUS protocol have been implemented in P30P transducers:
●
03 (03h) – readout of registers group
●
04 (04h) – readout of input registers group
●
06 (06h) – single register writing
●
16 (10h) – registers group writing
●
17 (11h) – slave device identification
Readout of n-registers (code 03h)
Example:
Readout of 2 registers, starting with the register address 1DB0h (7600) float (32-bit), (register
values 10, 100.)
Request:
Table 24
Device
address
Function
Register address
Number of registers
CRC
checksum
B1
B0
B1
B0
01h
03h
1Dh
B0h
00h
02h
C380h
Response:
Table 25
Device
address
Function
Number of
bytes
Value from the register
1DB0 (7600)
Value from the register
1DB1 (7601)
CRC
checksu
m
B3
B2
B1
B0
B3
B2
B1
B0
01h
03h
08h
41h
20h
00h
00h
42h
C8h
00h
00h
E46Fh
