This service is a component of MyEMS to acquire data from Modbus TCP devices.
mysql-connector-python
modbus_tk
schedule
python-decouple
telnetlib3
cd myems/myems-modbus-tcp
pip install -r requirements.txt
cp example.env .env
chmod +x run.sh
./run.sh
Refer to myems.io
Refer to myems.io
Download and install MySQL Connector:
cd ~/tools
wget https://cdn.mysql.com//Downloads/Connector-Python/mysql-connector-python-8.0.28.tar.gz
tar xzf mysql-connector-python-8.0.28.tar.gz
cd ~/tools/mysql-connector-python-8.0.28
python3 setup.py install
Download and install Schedule
cd ~/tools
git clone https://github.com/dbader/schedule.git
cd ~/tools/schedule
python3 setup.py install
Download and install Python Decouple
cd ~/tools
git clone https://github.com/henriquebastos/python-decouple.git
cd ~/tools/python-decouple
python3 setup.py install
Download and install modbus-tk
cd ~/tools
git clone https://github.com/pyserial/pyserial.git
cd ~/tools/pyserial
python3 setup.py install
git clone https://github.com/ljean/modbus-tk.git
cd ~/tools/modbus-tk
python3 setup.py install
Install myems-modbus-tcp service
cp -r myems/myems-modbus-tcp /myems-modbus-tcp
cd /myems-modbus-tcp
Create .env file based on example.env and edit the .env file if needed:
cp /myems-modbus-tcp/example.env /myems-modbus-tcp/.env
nano /myems-modbus-tcp/.env
Setup systemd service:
cp myems-modbus-tcp.service /lib/systemd/system/
Enable the service:
systemctl enable myems-modbus-tcp.service
Start the service:
systemctl start myems-modbus-tcp.service
Monitor the service:
systemctl status myems-modbus-tcp.service
View the log:
cat /myems-modbus-tcp.log
NOTE: If you modified Modbus TCP data sources and points, please restart this service:
systemctl restart myems-modbus-tcp.service
Input Data source protocol:
modbus-tcp
Data source connection example:
{"host":"10.9.67.99","port":502,"interval_in_seconds":60]}
Point address example:
{"slave_id":1, "function_code":3, "offset":0, "number_of_registers":2, "format":"<f", "byte_swap":true}
The slave ID
01 (0x01) Read Coils
02 (0x02) Read Discrete Inputs
03 (0x03) Read Holding Registers
04 (0x04) Read Input Registers
23 (0x17) Read/Write Multiple registers
The starting register address specified in the Request PDU
The number of registers specified in the Request PDU
Use python3 library struct to format bytes. Python bytes objects are used to hold the data representing the C struct and also as format strings (explained below) to describe the layout of data in the C struct.
The optional first format char indicates byte order, size and alignment: @: native order, size & alignment (default) =: native order, std. size & alignment <: little-endian, std. size & alignment >: big-endian, std. size & alignment !: same as >
The remaining chars indicate types of args and must match exactly; these can be preceded by a decimal repeat count: x: pad byte (no data); c:char; b:signed byte; B:unsigned byte; ?: _Bool (requires C99; if not available, char is used instead) h:short; H:unsigned short; i:int; I:unsigned int; l:long; L:unsigned long; f:float; d:double.
Special cases (preceding decimal count indicates length): s:string (array of char); p: pascal string (with count byte). Special cases (only available in native format): n:ssize_t; N:size_t; P:an integer type that is wide enough to hold a pointer.
Special case (not in native mode unless 'long long' in platform C): q:long long; Q:unsigned long long
Whitespace between formats is ignored.
A boolean indicates whether or not to swap adjacent bytes.
Swap adjacent bytes of 32bits(4bytes) or 64bits(8bytes).
This is not for little-endian and big-endian swapping, and use format for that.
The option is effective when number_of_registers is ether 2(32bits) or 4(64bits),
else it will be ignored.
[1]. http://myems.io
[2]. http://www.modbus.org/tech.php
[3]. https://github.com/ljean/modbus-tk
[4]. https://docs.python.org/3/library/struct.html#format-strings